oversight

Weapon System Sustainment: Aircraft Mission Capable Rates Generally Did Not Meet Goals and Cost of Sustaining Selected Weapon Systems Varied Widely

Published by the Government Accountability Office on 2020-11-19.

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                            U.S. GOVERNMENT ACCOUNTABILITY OFFICE




Weapon System Sustainment
Aircraft Mission Capable Rates Generally Did Not Meet Goals
and Cost of Sustaining Selected Weapon Systems Varied Widely
GAO-21-101SP                                                        November 2020
Report to Congressional Requesters




Source: U.S. Air Force/Master Sgt. Megan Crusher.
                                                                          Defense Capabilities and Management Team

Weapon System Sustainment
Aircraft Mission Capable Rates Generally Did Not Meet Goals
and Cost of Sustaining Selected Weapon Systems Varied Widely
Highlights of GAO-21-101SP, a report to congressional requesters                                                                                                         November 2020


    Mission Capable Rates for Selected Department of Defense Aircraft
GAO examined 46 types of aircraft and found that only three met their annual mission capable goals in a
majority of the years for fiscal years 2011 through 2019 and 24 did not meet their annual mission capable goals
in any fiscal year as shown below. The mission capable rate—the percentage of total time when the aircraft
can fly and perform at least one mission—is used to assess the health and readiness of an aircraft fleet.
Number of Times Selected Aircraft Met Their Annual Mission Capable Goal, Fiscal years 2011 through 2019
Air refueling                      KC-130T Hercules (Navy/Marine Corps)              0 of 9
                                  KC-130J Super Hercules (Marine Corps)              0 of 9
                                                 KC-10 Extender (Air Force)                                                 3 of 9
                                            KC-135 Stratotanker (Air Force)                                                 3 of 9
Anti-submarine                                         EP-3E Aries II (Navy)                                                                                           7 of 9
                                                     P-8A Poseidon (Navy)a                                     2 of 7
Bomber                                              B-1B Lancer (Air Force)          0 of 9
                                                        B-2 Spirit (Air Force)                                              3 of 9
                                              B-52 Stratofortress (Air Force)                                               3 of 9
Cargo                                               C-2A Greyhound (Navy)            0 of 9
                                                    C-130T Hercules (Navy)           0 of 9
                                             C-5M Super Galaxy (Air Force)                                     2 of 9
                                           C-17 Globemaster III (Air Force)          0 of 9
                                               C-130H Hercules (Air Force)                                     2 of 9
                                        C-130J Super Hercules (Air Force)            0 of 9
Command                                               E-2C Hawkeye (Navy)            0 of 9
and control                              E-2D Advanced Hawkeye (Navy)a               0 of 6
                       E-6B Mercury (Take Charge and Move Out) (Navy)                                                                                 5 of 9
            E-3 Sentry (Airborne Warning and Control System) (Air Force)                                                    3 of 9
                    E-4B National Airborne Operations Center (Air Force)                                                    3 of 9
          E-8C Joint Surveillance Target Attack Radar System (Air Force)                          1 of 9
Fighter                                             EA-18G Growler (Navy)                                      2 of 9
                                                   F/A-18A-D Hornet (Navy)                        1 of 9
                                            F/A-18E/F Super Hornet (Navy)            0 of 9
                       F-35C Lightning II Joint Strike Fighter (Joint/Navy)a                                   2 of 7
                                            AV-8B Harrier II (Marine Corps)          0 of 9
                                         F/A-18A-D Hornet (Marine Corps)             0 of 9
               F-35B Lightning II Joint Strike Fighter (Joint/Marine Corps)a                      1 of 7
                                             A-10 Thunderbolt II (Air Force)                      1 of 9
                                                  F-15C/D Eagle (Air Force)          0 of 9
                                              F-15E Strike Eagle (Air Force)                                                             4 of 9
                                            F-16 Fighting Falcon (Air Force)         0 of 9
                                                     F-22 Raptor (Air Force)         0 of 9
                   F-35A Lightning II Joint Strike Fighter (Joint/Air Force)a                                  2 of 8
Rotary                                                AH-64 Apache (Army)            0 of 9
                                                     CH-47 Chinook (Army)            0 of 9
                                              UH/HH-60 Black Hawk (Army)             0 of 9
                                                  MH-60R Seahawk (Navy)                                        2 of 9
                                                   MH-60S Seahawk (Navy)             0 of 9
                                                AH-1Z Viper (Marine Corps)           0 of 9
                                    CH-53E Super Stallion (Marine Corps)             0 of 9
                                            MV-22B Osprey (Marine Corps)             0 of 9
                                              UH-1Y Venom (Marine Corps)             0 of 9
                                                  CV-22 Osprey (Air Force)a          0 of 7
                                            HH-60G Pave Hawk (Air Force)                          1 of 9
                                                    UH-1N Huey (Air Force)                                                                                                                       9 of 9
                                                                                 0            1            2            3            4            5            6   7            8            9

                                                                                 Number of fiscal years

                                                                                              0 to 3 fiscal years                        4 to 6 fiscal years           7 to 9 fiscal years

Source: GAO analysis of Army, Navy, and Air Force data. | GAO-21-101SP

The military departments did not provide mission capable goals for all nine years for these aircraft.
a
Aggregating the trends at the military service level, the average annual mission capable rate for the selected
Air Force, Navy, and Marine Corps aircraft decreased since fiscal year 2011, while the average annual mission
capable rate for the selected Army aircraft slightly increased. While the average mission capable rate for the
F-35 Lightning II Joint Strike Fighter showed an increase from fiscal year 2012 to 2019, it trended downward
from fiscal year 2015 through fiscal year 2018 before improving slightly in fiscal year 2019.

For fiscal year 2019, GAO found only three of the 46 types of aircraft examined met the service-established
mission capable goal. Furthermore, for fiscal year 2019:

         •	 six aircraft were 5 percentage points or fewer below the goal;
         •	 18 were from 15 to 6 percentage points below the goal; and
         •	 19 were more than 15 percentage points below the goal, including 11 that were 25 or more percentage
            points below the goal.

Program officials provided various reasons for the overall decline in mission capable rates, including aging
aircraft, maintenance challenges, and supply support issues as shown below.
Sustainment Challenges Affecting Some of the Selected Department of Defense Aircraft
                                                       Aging aircraft                                  Maintenance                                      Supply support
                                              Delays in              Unexpected                         Shortage
                                                                                 Access to   Delays                             Diminishing                   Parts
                                              acquiring Service life replacement                        of trained Unscheduled                   Parts
                                                                                 technical  in depot                           manufacturing             ac shortage
                                            replacement extensiona of parts and                        maintenance maintenance               obsolescence
                                                                                   data    maintenance                           sourceab                   and delay
                                               aircraft                 repairs                         personnel
B-1B Lancer (Air Force)
C-5M Super Galaxy (Air Force)
C-130J Super Hercules (Air Force)
F/A-18E/F Super Hornet (Navy)
F-22 Raptor (Air Force)
MV-22B Osprey (Marine Corps)

Source: GAO analysis of Army, Navy, and Air Force information. | GAO-21-101SP
a
    A service life extension refers to a modification to extend the service life of an aircraft beyond what was planned.
b
    Diminishing manufacturing sources refers to a loss or impending loss of manufacturers or suppliers of items.
c
    Obsolescence refers to a lack of availability of a part due to its lack of usefulness or its no longer being current or available for production.



    Operating and Support Costs for Selected Department of Defense Aircraft
Operating and support (O&S) costs, such as the costs of maintenance and supply support, totaled over
$49 billion in fiscal year 2018 for the aircraft GAO reviewed and ranged from a low of $118.03 million for the
KC-130T Hercules (Navy) to a high of $4.24 billion for the KC-135 Stratotanker (Air Force). The trends in
O&S costs varied by aircraft from fiscal year 2011 to 2018. For example, total O&S costs for the F/A-18E/F
Super Hornet (Navy) increased $1.13 billion due in part to extensive maintenance needs. In contrast, the
F-15C/D Eagle (Air Force) costs decreased by $490 million due in part to a reduction in the size of the fleet.
Maintenance-specific costs for the aircraft types we examined also varied widely.

    Why This Matters                                                                             How GAO Did This Study
The Department of Defense (DOD) spends tens                                                     GAO was asked to report on the condition and costs
of billions of dollars annually to sustain its weapon                                           of sustaining DOD’s aircraft. GAO collected and
systems in an effort to ensure that these systems are                                           analyzed data on mission capable rates and O&S
available to simultaneously support today’s military                                            costs from the Departments of the Army, Navy, and
operations and maintain the capability to meet                                                  Air Force for fiscal years 2011 through 2019. GAO
future defense requirements. This report provides                                               reviewed documentation and interviewed program
observations on mission capable rates and costs to                                              office officials to identify reasons for the trends in
operate and sustain 46 fixed- and rotary-wing aircraft                                          mission capability rates and O&S costs as well as
in the Departments of the Army, Navy, and Air Force.                                            any challenges in sustaining the aircraft. This is a
                                                                                                public version of a sensitive report issued in August
     For more information, contact Director Diana                                               2020. Information on mission capable and aircraft
     Maurer at (202) 512-9627 or maurerd@gao.gov.                                               availability rates were deemed to be sensitive and
                                                                                                has been omitted from this report.
Contents


Letter                                                                              1
           Background                                                               5
           DOD Generally Did Not Meet Mission Capable Goals for Selected
              Aircraft, Mission Capable Rates Have Trended Downward, and
              Many Sustainment Challenges Exist                                     9
           O&S Costs and the Trends in Those Costs Varied across the
              Selected Aircraft                                                   15
           Sustainment Quick Looks for Selected DOD Aircraft                      19
           Air refueling aircraft                                                 21
              KC-130T Hercules (Navy/Marine Corps)                                22
              KC-130J Super Hercules (Marine Corps)                               26
              KC-10 Extender (Air Force)                                          31
              KC-135 Stratotanker (Air Force)                                     35
           Anti-submarine aircraft                                                39
              EP-3E Aries II (Navy)                                               40
              P-8A Poseidon (Navy)                                                44
           Bomber aircraft                                                        48
              B-1B Lancer (Air Force)                                             49
              B-2 Spirit (Air Force)                                              53
              B-52 Stratofortress (Air Force)                                     57
           Cargo aircraft                                                         61
              C-2A Greyhound (Navy)                                               62
              C-130T Hercules (Navy)                                              66
              C-5M Super Galaxy (Air Force)                                       70
              C-17 Globemaster III (Air Force)                                    74
              C-130H Hercules (Air Force)                                         78
              C-130J Super Hercules (Air Force)                                   82
           Command and control aircraft                                           86
              E-2C Hawkeye (Navy)                                                 87
              E-2D Advanced Hawkeye (Navy)                                        91
              E-6B Mercury (Take Charge and Move Out) (Navy)                      95
              E-3 Sentry (Airborne Warning and Control System) (Air Force)        99
              E-4B National Airborne Operations Center (Air Force)               103
              E-8C Joint Surveillance Target Attack Radar System (Air Force)     107
           Fighter aircraft                                                      113
              EA-18G Growler (Navy)                                              114
              F/A-18A-D Hornet (Navy/Marine Corps)                               118
              F/A-18E/F Super Hornet (Navy)                                      122
              F-35 Lightning II Joint Strike Fighter (Navy/Marine Corps/Air
                 Force)                                                          126
              AV-8B Harrier II (Marine Corps)                                    134
              A-10 Thunderbolt II (Air Force)                                    139


           Page i                               GAO-21-101SP Weapon System Sustainment
                 F-15C/D Eagle (Air Force)                                           144
                 F-15E Strike Eagle (Air Force)                                      148
                 F-16 Fighting Falcon (Air Force)                                    152
                 F-22 Raptor (Air Force)                                             156
               Rotary aircraft                                                       160
                 AH-64 Apache (Army)                                                 161
                 CH-47 Chinook (Army)                                                165
                 UH/HH-60 Black Hawk (Army)                                          170
                 MH-60R Seahawk (Navy)                                               174
                 MH-60S Seahawk (Navy)                                               178
                 AH-1Z Viper (Marine Corps)                                          182
                 CH-53E Super Stallion (Marine Corps)                                186
                 MV-22B Osprey (Marine Corps)                                        190
                 UH-1Y Venom (Marine Corps)                                          195
                 CV-22 Osprey (Air Force)                                            199
                 HH-60G Pave Hawk (Air Force)                                        204
                 UH-1N Huey (Air Force)                                              209
               Agency Comments                                                       213

Appendix I     Objectives, Scope, and Methodology                                    215



Appendix II    Additional Information on Navy Aircraft Mission Capable Rates         220



Appendix III   GAO Contact and Staff Acknowledgments                                 221


Figures
               Figure 1: Number of Times Selected Aircraft Met Their Annual
                        Mission Capable Goal, Fiscal Years 2011 through 2019          10
               Figure 2: Sustainment Challenges Affecting Selected Department
                        of Defense Aircraft                                           14
               Figure 3: Annual Operating and Support Costs per Aircraft for
                        Selected Department of Defense Aircraft, Fiscal Year
                        2018                                                          18
               Figure 4: Aircraft Selected for Review by GAO                         216




               Page ii                              GAO-21-101SP Weapon System Sustainment
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Page iii                                       GAO-21-101SP Weapon System Sustainment
                       Letter




441 G St. N.W.
Washington, DC 20548




                       November 19, 2020

                       Congressional Requesters

                       The Department of Defense (DOD) spends tens of billions of dollars
                       annually to sustain its weapon systems in an effort to ensure that these
                       systems are available to simultaneously support today’s military
                       operations and maintain the capability to meet future defense
                       requirements. Operating and support (O&S) costs historically account for
                       approximately 70 percent of a weapon system’s total life-cycle cost—
                       costs to operate and sustain the weapon system from initial operations
                       through the end of its life—and include costs for repair parts, depot and
                       field maintenance, contract services, engineering support, and personnel,
                       among other things. 1 Weapon systems are costly to sustain, in part
                       because they often incorporate a complex array of technical subsystems
                       and components and need expensive repair parts and logistics support to
                       meet required readiness levels. Aircraft are one type of weapon system
                       sustained by DOD that allow it to conduct its mission.

                       One of the key metrics used by DOD and the military services to assess
                       the health and readiness of an aircraft fleet is mission capable rate—that
                       is, the percentage of total time when the aircraft can fly and perform at
                       least one mission. 2 For example, the F-22 Raptor (Air Force) has two
                       primary air-to-air focused missions and one secondary air-to-ground



                       1There   are two levels of DOD maintenance: field-level and depot-level. Field-level
                       maintenance includes organizational and intermediate maintenance and requires fewer
                       skills, but occurs more frequently. Depot-level maintenance occurs less frequently but
                       requires greater skills. Specifically, depot maintenance is an action performed on materiel
                       or software in the conduct or inspection, repair, overhaul, or modification or rebuild of end
                       items, assemblies, subassemblies, and parts that, among other things, requires extensive
                       industrial facilities, specialized tools and equipment, or uniquely experienced and trained
                       personnel that are not available in other maintenance activities. Depot maintenance is
                       independent of any location or funding source and may be performed in the public or
                       private sectors. See GAO, Depot Maintenance: Executed Workload and Maintenance
                       Operations at DOD Depots, GAO-17-82R (Washington, D.C.: Feb. 3, 2017), for additional
                       information on the workload executed across the military services’ depots as well as
                       challenges confronted by each of DOD’s 17 depots.
                       2The  military services also measure whether systems are full mission capable (that is, can
                       perform all of their assigned missions). We do not discuss full mission capable rates in this
                       report.




                       Page 1                                          GAO-21-101SP Weapon System Sustainment
mission and would be considered mission capable if it could fulfill only
one of these missions. 3

Each military department determines a mission capable goal for its
aircraft, and tracks and reports aircraft mission capable rates. 4 For
example, for fiscal year 2018, the Navy’s EA-18G Growler had a mission
capable goal of 75 percent. 5 In addition, in September 2018 the Secretary
of Defense issued a memo directing that the F-22 Raptor (Air Force), F-
16 Fighting Falcon (Air Force), F-35 Lighting II Joint Strike Fighter (Joint
Program), and F/A-18 aircraft—specifically, the F/A-18A-D Hornet (Navy
and Marine Corps), F/A-18E/F Super Hornet (Navy), and EA-18G Growler
(Navy)—achieve a minimum 80 percent mission capable rate by the end
of fiscal year 2019. 6

You requested that we report on the condition and O&S costs for
additional major weapon systems. 7 This report provides observations on
(1) the extent to which the military services met mission capable goals for
3The  two primary air-to-air missions of the F-22 are Offense Counter-Air—Escort/Sweep
and Defensive Counter-Air. The secondary air-to-ground mission of the F-22 is Air
Interdiction/Offensive Counter-Air—Attack Operations. For further details on the F-22, see
GAO, Force Structure: F-22 Organization and Utilization Changes Could Improve Aircraft
Availability and Pilot Training, GAO-18-190 (Washington, D.C.: July 19, 2018).
4Inthe Air Force, the lead commands set the aircraft mission capable goals in
coordination with the applicable program office and Maintenance Division.
5In 2018, in our first weapon-system sustainment assessment, we reported that between
fiscal years 2011 and 2016 the Air Force and the Navy generally did not meet aircraft
availability goals, and O&S cost trends for 12 fixed-wing aircraft varied. See GAO,
Weapon System Sustainment: Selected Air Force and Navy Aircraft Generally Have Not
Met Availability Goals, and DOD and Navy Guidance Need Clarification, GAO-18-146SU
(Washington, D.C.: Apr. 25, 2018). In addition, we conduct annual assessments of DOD’s
major defense acquisition programs and report on the cost, schedule, and performance of
those programs. See GAO, Defense Acquisitions Annual Assessment: Drive to Deliver
Capabilities Faster Increases Importance of Program Knowledge and Consistent Data for
Oversight, GAO-20-439 (Washington, D.C.: June 3, 2020), for our most recent annual
assessment.
6Secretary of Defense Memorandum, NDS Implementation—Mission Capability of Critical
Aviation Platforms (Sept. 17, 2018).
7The Conference Report accompanying a bill for the Department of Defense and Labor,
Health and Human Services, and Education Appropriations Act, 2019 and Continuing
Appropriations Act, 2019, also included a provision for us to report on the maintenance of
the E-8C Joint Surveillance Target Attack Radar System. H.R. Rep. No. 115-952 (2018)
(Conf. Rep). This report addresses this provision as it includes detailed information on the
E-8C Joint Surveillance Target Attack Radar System, including its depot maintenance
program.




Page 2                                          GAO-21-101SP Weapon System Sustainment
46 fixed- and rotary-wing types of aircraft, including trends since fiscal
year 2011 in mission capable rates and any sustainment challenges for
those aircraft; and (2) the costs to operate and support these aircraft
since fiscal year 2011. In addition, we provide 43 individual “Sustainment
Quick Looks,” some of which cover multiple aircraft that are similar but
have separate mission capable goals and are reported separately by
DOD and the military services. These Sustainment Quick Looks include
detailed information on mission capable rates and other sustainment
information, O&S costs, and sustainment challenges and mitigation
actions to address these challenges.

This is a public version of a sensitive report that we issued in August
2020. 8 DOD deemed some of the information in our August report to be
sensitive (i.e., For Official Use Only), which must be protected from public
disclosure. Therefore, this report omits sensitive information about
mission capable and aircraft availability rates. Although the information
provided in this report is more limited, the report addresses the same
objectives as the sensitive report and uses the same methodology.

Our observations are based on 46 manned fixed- and rotary-wing types of
aircraft that support combat-related missions in the Departments of the
Army, Navy, and Air Force. 9 In selecting these aircraft, we considered a
number of factors, such as the mission of the aircraft (e.g., fighters,
bombers, or cargo) and the size and age of the inventory for each aircraft.
For example, we did not select aircraft that are used solely for training or
are used to meet the operational airlift support mission (i.e., the
movement of a limited number of high-priority passengers and cargo with
time, place, or mission-sensitive requirements). 10

For objective one, we collected and analyzed data from the Army, Navy,
and Air Force on key sustainment metrics for each of the 46 aircraft,
including mission capable rates and goals for fiscal years 2011 through
2019, the last fiscal year for which complete data were available at the
8GAO, Weapon System Sustainment: Aircraft Mission Capable Rates Generally Did Not
Meet Goals and Cost of Sustaining Selected Weapon Systems Varied Widely,
GAO-20-67SPSU (Washington, D.C.: August 27, 2020).
9Aircraft   flown by the Marine Corps are included in the data on the Department of the
Navy.
10We reported on operational support airlift in June 2017. See GAO, Operational Support
Airlift: Fleet Sufficiency Is Assessed Annually, GAO-17-582 (Washington, D.C.: June 28,
2017).




Page 3                                           GAO-21-101SP Weapon System Sustainment
time of our work. We selected this time frame so that we could identify
and obtain insight on mission capable rate trends. We also obtained
information from program office officials regarding the reasons for
changes in mission capable rates as well as any challenges in sustaining
these aircraft.

For objective two, we collected and analyzed O&S data from the
Departments of the Army, Navy, and Air Force cost reporting systems. 11
Specifically, we collected O&S cost data for fiscal years 2011 through
2018, the last fiscal year for which complete data were available at the
time of our work. We selected this time frame so that we could identify
and obtain insight on the historical data trends regarding O&S costs. We
also spoke to and obtained information from program office officials about
the reasons for changes and trends in O&S costs.

We conducted data-reliability assessments for the data provided by the
military departments and the F-35 Joint Program Office. To do this, we
reviewed related documentation; held interviews with knowledgeable
agency officials; and performed electronic data testing for missing data,
outliers, and obvious errors. As a result, we determined these data to be
sufficiently reliable for the purposes of summarizing trends in mission
capable rates and O&S costs since fiscal year 2011. 12 Appendix I
provides further information on our scope and methodology.

We conducted this performance audit from August 2018 to July 2020 in
accordance with generally accepted government auditing standards.
Those standards require that we plan and perform the audit to obtain
sufficient, appropriate evidence to provide a reasonable basis for our
findings and conclusions based on our audit objectives. We believe that
the evidence obtained provides a reasonable basis for our findings and
conclusions based on our audit objectives. We subsequently worked with
DOD from August 2020 to November 2020 to prepare this unclassified
version of the original sensitive report for public release. This public
version was also prepared in accordance with these standards.


11Specifically,
             we obtained information from the Army Operating and Support
Management Information System (OSMIS), the Navy Visibility and Management of
Operating and Support Costs system (VAMOSC), and the Air Force Total Ownership Cost
system (AFTOC).
12We  report on Army O&S costs through fiscal year 2017. We obtained fiscal year 2018
O&S cost data from the Army and discussed these data with the program office officials,
who informed us that the data were incorrect. The Army did not provide updated data.




Page 4                                        GAO-21-101SP Weapon System Sustainment
Background
Roles and Responsibilities   There are a variety of DOD offices that have roles and responsibilities
for the Sustainment of       related to sustaining fixed- and rotary-wing aircraft. For example, the
                             Under Secretary of Defense for Acquisition and Sustainment (USD [A&S])
Aircraft
                             is the principal advisor to the Secretary of Defense for all matters
                             concerning acquisition and sustainment. Specifically, USD (A&S) is
                             responsible for establishing policies for logistics, maintenance, and
                             sustainment support for all elements of DOD, including fixed- and rotary-
                             wing aircraft. The Assistant Secretary of Defense for Sustainment (ASD
                             [Sustainment]) serves as the principal advisor to the USD (A&S) on
                             logistics and materiel readiness within DOD. Specifically, the ASD
                             (Sustainment) (1) establishes DOD policies and procedures for logistics,
                             maintenance, materiel readiness, strategic mobility, and sustainment
                             support; (2) provides related guidance to the Secretaries of the military
                             departments; and (3) monitors and reviews programs associated with
                             these areas, among other duties and responsibilities.

                             For the Air Force, the Air Force Materiel Command develops, acquires,
                             and sustains weapon systems through research, development, testing,
                             evaluation, acquisition, maintenance, and program management of the
                             systems and their components. This command provides acquisition and
                             life-cycle management services and logistics support, among other
                             things. The Air Force Life Cycle Management Center within the Air Force
                             Materiel Command is responsible for the life-cycle management of
                             weapon systems from inception to retirement. A Program Executive
                             Officer—responsible for managing a specific portfolio of weapon
                             systems—is responsible for each of the selected fixed- and rotary-wing
                             aircraft. The Program Executive Officer oversees the program office that
                             manages each weapon system. The Air Force Sustainment Center, a
                             subordinate organization of the Air Force Materiel Command, provides
                             depot maintenance through its Air Logistics Complexes for weapon
                             systems. 13

                             For the Navy and Marine Corps, the Naval Air Systems Command is
                             responsible for providing the full life-cycle support of naval aviation

                             13The  Department of the Air Force operates three Air Logistics Complexes that perform
                             depot-level maintenance. These complexes are located in Ogden, Utah; Oklahoma City,
                             Oklahoma; and Warner Robins, Georgia. Each has been designated as a Center for
                             Industrial and Technical Excellence (CITE) to focus on the maintenance and repair of
                             specific aircraft, systems, and equipment.




                             Page 5                                       GAO-21-101SP Weapon System Sustainment
aircraft, weapons, and systems. This support includes research, design,
development, and systems engineering; acquisition; test and evaluation;
training facilities and equipment; repair and modification; and in-service
engineering and logistics support. As with the Air Force, Program
Executive Officers oversee their assigned program managers. Naval Air
Systems Command is also responsible for the Navy Fleet Readiness
Centers, which provide depot-level maintenance for Navy and Marine
Corps fixed- and rotary-wing aircraft. 14

The Army Materiel Command is the Army’s primary logistics and
sustainment command, responsible for managing the global supply chain
and ensuring installation and materiel readiness. The Army’s Aviation and
Missile Command (AMCOM)—a subordinate command of Army Materiel
Command—is a life-cycle management command that works to integrate
sustainment, logistics, and contracting in order to support the product life-
cycle management efforts. Within AMCOM, the AMCOM Logistics Center
provides readiness support for aviation and missile weapon systems,
including sustainment logistics, supply chain management, and field and
sustainment maintenance. Individual program managers work closely with
AMCOM to manage their aircraft sustainment programs. The Army
Materiel Command also provides depot-level maintenance through its
depots. 15

DOD relies on program managers to lead the development, delivery, and
sustainment of individual weapon systems through their life cycles. The
program managers are the designated individuals with responsibility for
accomplishing the program’s sustainment objectives to meet the users’
operational needs. Product support managers, who work within the
program offices, are responsible for developing and implementing support
strategies for weapon systems that maintain readiness and control life-

14The  Department of the Navy operates three major Fleet Readiness Centers in Cherry
Point, North Carolina (East); Jacksonville, Florida (Southeast); and North Island, California
(Southwest), that perform depot-level maintenance. As with the Air Force, each has been
designated as a CITE, and all three are CITEs for sea-based and maritime aircraft and the
related aeronautical systems.
15The  Department of the Army operates two depots that support aircraft: Corpus Christi
Army Depot, Texas and Tobyhanna Army Depot, Pennsylvania. Corpus Christi Army
Depot is the Army’s CITE for the maintenance and repair of structural helicopter airframes
and blades; advanced composite technologies; flight controls and control surfaces; and
aviation engines, transmissions, and hydraulic systems. Tobyhanna Army Depot is the
Army’s CITE for the maintenance and repair of systems associated with command,
control, communications, and computers; intelligence, surveillance, and reconnaissance;
electronics; avionics; and missile control.




Page 6                                          GAO-21-101SP Weapon System Sustainment
                          cycle costs. Weapon systems are sustained under various arrangements
                          that may include contractors, DOD organic facilities, or some combination
                          of the two.

                          Additionally, the Air Force Sustainment Center, the Navy Supply Systems
                          Command, and Army Materiel Command, as well as the Defense
                          Logistics Agency, manage inventories of spare parts. Further, individual
                          weapon systems programs are typically supported by a complex supplier
                          network that includes a prime contractor, subcontractors, and various
                          tiers of parts suppliers. Sustainment responsibilities—either in their
                          entirety, or particular elements—may also be contracted out as part of a
                          public-private partnership or a performance-based logistics agreement,
                          such as is the case with the F-22 Raptor. 16

Key Sustainment Metrics   The services monitor the readiness status of aircraft through multiple
for Aircraft              performance metrics. This report provides information on, among other
                          things, three metrics that the Air Force, Navy, and Army have in common:

                          •   Mission capable rate: The percentage of total time when an aircraft
                              can fly and perform at least one mission.
                          •   Not mission capable maintenance (NMCM) rate: The percentage of
                              total time when an aircraft is not capable of performing any of its
                              assigned missions because of maintenance.
                          •   Not mission capable supply (NMCS) rate: The percentage of total
                              time when an aircraft is not capable of performing any of its assigned
                              missions because of the lack of a repair part.
                          In addition to these metrics, the Air Force measures aircraft availability,
                          the number of aircraft that are available for flight operations, and not
                          mission capable for both supply and maintenance (NMCB), aircraft that
                          are not in depot and not capable of performing any of their assigned
                          missions because of both maintenance and the lack of a repair part.
                          Lastly, the Navy tracks not mission capable depot (NMCD)—aircraft that

                          16According to DOD Instruction 4151.21, Public-Private Partnerships for Product Support
                          (Apr. 25, 2007) (incorporating Change 4, effective July 31, 2019), a public-private
                          partnership for depot-level maintenance is a cooperative arrangement between an organic
                          depot-level maintenance activity and one or more private-sector entities to perform DOD
                          or defense-related work and/or to utilize DOD depot facilities and equipment. According to
                          DOD’s Performance-Based Logistics Guidebook (2016), performance-based logistics is
                          synonymous with performance-based life-cycle product support, where outcomes are
                          acquired through performance-based arrangements that deliver warfighter requirements
                          and incentivize product support providers to reduce costs through innovation. These
                          arrangements are contracts with industry or intragovernmental agreements.




                          Page 7                                        GAO-21-101SP Weapon System Sustainment
                         are not capable of performing any assigned missions because of
                         standard or special rework that is required, such as depot maintenance,
                         special inspections, or modifications.

Operating and Support    O&S costs historically account for approximately 70 percent of a weapon
Costs for Major Weapon   system’s total life-cycle cost and include costs for repair parts, depot and
                         field maintenance, contract services, engineering support, and personnel,
Systems
                         among other things. DOD’s Operating and Support Cost-Estimating
                         Guide provides direction to the service components on developing
                         estimates to support various analyses and reviews throughout the
                         program life cycle. 17 According to the guide, as a program matures, it
                         remains necessary to continue to track and assess O&S costs and trends
                         to ensure that the program remains sustainable, affordable, and properly
                         funded. Each military department maintains a database that collects
                         historical data on the O&S costs for major fielded weapon systems. 18
                         DOD’s Office of Cost Assessment and Program Evaluation provides
                         policy guidance on this requirement, known as the Visibility and
                         Management of Operating and Support Costs program; specifies the
                         common format in which the data are to be reported; and monitors its
                         implementation by each of the military departments. O&S costs are
                         categorized using the following six overarching elements: 19

                         •   unit level manpower—cost of operators, maintainers, and other
                             support manpower assigned to operating units;
                         •   unit operations—cost of unit operating materiel, such as fuel, and
                             training material, unit support services, and unit travel;
                         •   maintenance—cost of system maintenance, including depot- and
                             intermediate-level maintenance;


                         17Department of Defense, Office of Cost Assessment and Program Evaluation, Operating
                         and Support Cost-Estimating Guide (March 2014).
                         18The  Air Force uses the Air Force Total Ownership Cost system, the Army uses the
                         Operating and Support Cost Management Information System, and the Navy uses the
                         Navy Visibility and Management of Operating and Support Costs system to collect and
                         report on historical weapon system O&S costs.
                         19These  six elements are further classified into additional subcategories. The maintenance
                         cost elements for the Army and the Navy are further classified into five subcategories,
                         including consumable materials and repair parts, depot-level reparables, depot
                         maintenance, intermediate maintenance, and other maintenance. The Air Force’s
                         maintenance cost element is further classified into six subcategories, including
                         consumable materials and repair parts, contractor logistics support, depot-level
                         reparables, depot maintenance, interim contractor support, and other maintenance.




                         Page 8                                         GAO-21-101SP Weapon System Sustainment
                          •   sustaining support—cost of system support activities that are
                              provided by organizations other than the system’s operating units;
                          •   continuing system improvements—cost of system hardware and
                              software modifications; and
                          •   indirect support—cost of activities that provide general services that
                              lack the visibility of actual support to specific force units or systems.



DOD Generally Did
Not Meet Mission
Capable Goals for
Selected Aircraft,
Mission Capable
Rates Have Trended
Downward, and Many
Sustainment
Challenges Exist

DOD Has Generally Not     We found that of the 46 individual fixed- and rotary-wing types of aircraft
Met Established Mission   we examined, only three met the service-established mission capable
                          goal for fiscal year 2019. Furthermore, for fiscal year 2019:
Capable Goals for
Selected Aircraft         •   six aircraft were 5 percentage points or fewer below the goal;
                          •   18 were from 15 to 6 percentage points below the goal; and
                          •   19 were more than 15 percentage points below the goal, including 11
                              that were 25 or more percentage points below the goal.
                          In addition, we found that 24 aircraft in our review did not meet their
                          annual mission capable goals for any year from fiscal year 2011 through
                          fiscal year 2019 and only three met their annual mission capable goals in
                          a majority of those years, as shown in figure 1 below. Specific details on
                          the rates for each type of aircraft were omitted because the information
                          was deemed by DOD to be sensitive.




                          Page 9                                  GAO-21-101SP Weapon System Sustainment
Figure 1: Number of Times Selected Aircraft Met Their Annual Mission Capable Goal, Fiscal Years 2011 through 2019




                                        a
                                         DOD did not provide mission capable goals for all nine years for these aircraft.




                                        Page 10                                               GAO-21-101SP Weapon System Sustainment
Aircraft Did Not Meet the      As previously discussed, in September 2018 the Secretary of Defense
Secretary of Defense’s 80      issued a memorandum emphasizing that a key component of
Percent Mission Capable Goal   implementing the 2018 National Defense Strategy is ensuring the mission
                               capability of critical aviation platforms. 20 In addition to the mission capable
                               goals established by the military departments for each aircraft, the
                               memorandum established an 80 percent mission capable goal for the F-
                               22 Raptor (Air Force), F-16 Fighting Falcon (Air Force), F-35 Lighting II
                               Joint Strike Fighter (Joint Program), and F/A-18 inventories (Navy)—
                               including the F/A-18A-D Hornet, F/A-18E/F Super Hornet, and EA-18G
                               Growler—by the end of fiscal year 2019. 21 We reported in December
                               2018 that program officials within DOD and the Navy told us this goal
                               would be challenging to achieve by the end of fiscal year 2019. 22

                               We found that none of these aircraft had achieved the 80 percent mission
                               capable goal, when mission capable rate data are averaged for each day
                               in fiscal year 2019. Secretary of Defense Mark Esper, in responding to
                               advance policy questions for his July 2019 Senate Armed Services
                               Committee nomination hearing, stated that the F-35 Lighting II Joint Strike
                               Fighter fleet (i.e., the F-35A [Air Force], F-35B [Marine Corps], and F-35C
                               [Navy]) was not expected to reach an 80 percent mission capable rate by
                               the end of fiscal year 2019. Additionally, Secretary Esper noted that the
                               F-22 Raptor (Air Force) fleet was not expected to achieve the 80 percent
                               goal due to challenges associated with low-observable maintenance
                               capacity that were exacerbated by the extreme damage at Tyndall Air
                               Force Base from the effects of Hurricane Michael. In February 2020, F-16
                               Fighting Falcon (Air Force) program office officials also acknowledged
                               that, despite some improvement, the F-16 had not achieved the
                               Secretary’s 80 percent goal.



                               20Secretary  of Defense Memorandum, NDS Implementation—Mission Capability of Critical
                               Aviation Platforms (Sept. 17, 2018).
                               21Implementing     guidance for this goal specifies that it applies only to F-35 aircraft acquired
                               in low-rate initial production lot 6 or later. Low-rate initial production establishes the initial
                               production base for the system or capability increment, provides an efficient ramp-up to
                               full-rate production, and maintains continuity in production pending operational test and
                               evaluation completion. The mission capable rate of these aircraft is slightly higher than the
                               mission capable rate of the entire F-35 fleet. See Office of the Under Secretary of
                               Defense, Personnel and Readiness, Memorandum, NDS Implementation—Mission
                               Capability of Critical Aviation Platform Metrics (Nov. 27, 2018).
                               22GAO,  Navy and Marine Corps: Rebuilding Ship, Submarine, and Aviation Readiness
                               Will Require Time and Sustained Management Attention, GAO-19-225T (Washington,
                               D.C.: Dec.12, 2018).




                               Page 11                                           GAO-21-101SP Weapon System Sustainment
                         The Navy publicly reported in late September 2019 that it had met the
                         Secretary’s 80 percent mission capable goal for the F/A-18E/F Super
                         Hornet and EA-18G Growler. Our analysis showed that mission capable
                         rates generally did improve for these Navy systems over the course of
                         fiscal year 2019, including meeting the 80 percent mission capable rate at
                         particular points of time in fiscal year 2019. However, we found that none
                         of these aircraft achieved the mission capable goal when mission capable
                         rate data were averaged for each day in fiscal year 2019. Navy officials
                         noted that the Navy continues to work at sustaining the progress made
                         during fiscal year 2019. The details of our analysis of these rates were
                         omitted because the information was deemed by DOD to be sensitive.

                         Air Force Chief of Staff General Charles Q. Brown, Jr., in responding to
                         advance policy questions from the Senate Armed Services Committee for
                         his nomination hearing in May 2020, stated that the Office of the
                         Secretary of Defense had determined that the fiscal year 2019 80 percent
                         mission capable goal is not a fiscal year 2020 requirement. An Office of
                         the Secretary of Defense official stated that the department had decided
                         to move away from a goal that narrowly focused on selected aircraft and
                         had expanded to a more holistic view of readiness.

The Navy Uses Two        During the process of conducting our analysis, we determined that the
Approaches to Measure    Navy has two information technology systems that track mission capable
Mission Capable Rates,   rates. These systems use separate approaches, resulting in different
Resulting in Different   outcomes. According to Navy officials, the Navy uses mission capable
Outcomes                 rate data from its Aviation Maintenance Supply Readiness Reporting
                         (AMSRR) information technology system to evaluate its progress against
                         the Secretary’s 80 percent mission capable goal. 23 These officials further
                         stated that the AMSRR data they are using to track progress against the
                         Secretary’s 80 percent mission capable goal allows for a better
                         assessment of the Navy’s ability to “fight tonight” as it measures mission
                         capability at a point in time on each day.

                         The Navy also maintains mission capable rate data as well as other
                         sustainment data in its Decision Knowledge Programming for Logistics
                         Analysis and Technical Evaluation (DECKPLATE) information technology
                         system. Navy officials acknowledge that DECKPLATE data provide a
                         more comprehensive measure of the health of aircraft, systems, and
                         components as they measure mission capability based on a percentage


                         23Secretary  of Defense Memorandum, NDS Implementation—Mission Capability of Critical
                         Aviation Platforms (Sept. 17, 2018).




                         Page 12                                     GAO-21-101SP Weapon System Sustainment
                             of the total time the aircraft is available. As a result, in this report we used
                             sustainment data from DECKPLATE in our Sustainment Quick Looks for
                             the Navy and Marine Corps aircraft, as well as in any summary
                             information on mission capable rates that are not related to the
                             Secretary’s 80 percent goal.

                             The Navy’s AMSRR mission capable rates for fiscal year 2019 are higher
                             for the 19 Navy and Marine Corps aircraft than the DECKPLATE mission
                             capable rates for those aircraft for the same fiscal year. While three
                             aircraft—EP-3E Aries II, E-6B Mercury, and F/A-18A-D Hornet—met the
                             service’s goals using AMSRR mission capable rate data, one aircraft met
                             the service’s mission capable goal for fiscal year 2019 using the
                             DECKPLATE mission capable rates. 24 As there are trade-offs to the
                             different approaches, we did not evaluate the efficacy of the Navy’s
                             tracking and reporting of mission capable rates and are not making any
                             related recommendations.

Mission Capable Rates        Average mission capable rates for the selected Air Force, Navy, and
Generally Trended            Marine Corps aircraft have fallen since fiscal year 2011, while average
                             mission capable rates for the selected Army aircraft have slightly risen.
Downward from Fiscal
                             While the average mission capable rate for the F-35 Lightning II Joint
Year 2011 through Fiscal     Strike Fighter showed an increase from fiscal year 2012 through fiscal
Year 2019 for the Selected   year 2019, it trended downward from fiscal year 2015 through fiscal year
Aircraft                     2018, before improving slightly in fiscal year 2019. Specific details of
                             these rates were omitted because the information was deemed by DOD
                             to be sensitive.

Wide Variety of              Program officials provided various reasons for the overall decline in
Sustainment Challenges       mission capable rates, including aging aircraft, maintenance challenges,
                             and supply support issues. These challenges are summarized and
for the Selected DOD
                             presented in figure 2 below.
Aircraft




                             24In appendix II we present AMSRR mission capable rates for each of the aircraft against
                             the Navy’s or Marine Corps’ goals and a comparison of the AMSRR and DECKPLATE
                             mission capable rate data for each aircraft. We also provide additional technical details on
                             the differences between the AMSRR and DECKPLATE systems and implications for
                             reported mission capable rates.




                             Page 13                                         GAO-21-101SP Weapon System Sustainment
Figure 2: Sustainment Challenges Affecting Selected Department of Defense Aircraft




                                        Page 14                                      GAO-21-101SP Weapon System Sustainment
                        a
                         A service life extension refers to a modification to extend the service life of an aircraft beyond what
                        was planned.
                        b
                         Diminishing manufacturing sources refers to a loss or impending loss of manufacturers or suppliers
                        of items.
                        c
                          Obsolescence refers to a lack of availability of a part due to its lack of usefulness or its no longer
                        being current or available for production.


                        While mission capable rates have primarily declined since fiscal year
O&S Costs and the       2011, O&S costs and the trends in these costs have varied across
Trends in Those         aircraft, for a variety of reasons. In fiscal year 2018, O&S costs for the
                        aircraft in our review that provided us with O&S cost data totaled $49.33
Costs Varied across     billion. 25 Specifically, the total fiscal year 2018 O&S costs for the aircraft
the Selected Aircraft   we reviewed ranged from a low of $118.03 million for the Navy’s fleet of
                        KC-130T Hercules to a high of $4.24 billion for the Air Force’s fleet of KC-
                        135T Stratotankers, with a key factor being the size of the fleet.
                        Maintenance costs for the aircraft in our review that provided us with O&S
                        cost data totaled $21.52 billion (or 44 percent of the total O&S costs) in
                        fiscal year 2018. 26 Maintenance costs also varied widely across the
                        aircraft, due to the size of the aircraft fleet and the particular challenges
                        associated with the aircraft. For example, maintenance costs ranged from
                        $43.91 million for the Navy’s fleet of KC-130T Hercules to $2.02 billion for
                        the Air Force’s fleet of C-130H Hercules in fiscal year 2018.

                        The trends in total O&S costs from fiscal year 2011 through fiscal year
                        2018 varied by aircraft, either increasing, remaining consistent, or
                        decreasing, as detailed below:

                        •    Increased: Twenty aircraft in our review experienced increasing total
                             O&S costs, including the MH-60R Seahawk (Navy), the E-2D
                             Advanced Hawkeye (Navy), and the F/A18-E/F (Navy). For example,
                             both the MH-60R Seahawk and the E-2D Advanced Hawkeye
                             experienced increasing O&S costs, largely due to an increase in fleet
                             size, according to program officials. Specifically, total costs for the
                             MH-60R Seahawk fleet increased from about $398.50 million in fiscal
                             year 2011 to $1.19 billion in fiscal year 2018, while total O&S costs for
                             the E-2D fleet increased from $1.54 million in fiscal year 2012 (the

                        25The  total O&S costs do not include the Army aircraft—AH-64 Apache, CH-47 Chinook,
                        and HH/UH-60 Black Hawk. We obtained fiscal year 2018 O&S cost data from the Army,
                        but we learned from the Army that the data were inaccurate. In fiscal year 2017, O&S
                        costs for these three aircraft totaled about $2.79 billion.
                        26These  total fiscal year 2018 maintenance costs do not include the Army aircraft, as
                        previously discussed. In fiscal year 2017, maintenance costs for the three Army aircraft
                        totaled about $1.03 billion.




                        Page 15                                                 GAO-21-101SP Weapon System Sustainment
    first year during which the aircraft incurred significant O&S costs) to
    $228.75 million in fiscal year 2018.The total O&S costs for the F/A-
    18E/F Super Hornet (Navy) increased by $1.13 billion—from $2.16
    billion to $3.29 billion—from continuing systems improvements, the
    results of sustained high flight hours, and to address extensive
    maintenance needs associated with extending the service life of the
    aircraft, among other reasons, according to program officials.
•   Consistent: Three aircraft—the F-22 Raptor (Air Force), the UH-1N
    Huey (Air Force), and the B-2 Spirit (Air Force)—had generally
    consistent O&S costs from fiscal year 2011 through fiscal year 2018,
    with O&S costs in fiscal year 2018 that were within 5 percent or less
    of the O&S costs in fiscal year 2011. 27 For example, O&S costs for
    the B-2 fleet increased from $859.31 million in fiscal year 2011 to
    $885.49 million in fiscal year 2018, an increase of 3 percent.
•   Decreased: Twenty-two aircraft had decreasing fleet-wide O&S costs,
    including the E-2C Hawkeye (Navy), A-10 Thunderbolt II (Air Force),
    AV-8B Harrier II (Marine Corps), KC-10 Extender (Air Force), and C-
    17 Globemaster III (Air Force). There were various reasons for these
    decreases. For example, the Air Force decreased the flight hours of
    the C-17 Globemaster III, resulting in lower O&S costs for the fleet,
    according to program officials. An AV-8B program office official stated
    that the fleet-wide O&S costs decreased because of the transition to
    the F-35B Lightning II Joint Strike Fighter, as well as less utilization of
    the AV-8B after Operation Iraqi Freedom and Operation Enduring
    Freedom, among other reasons. Further, as the Air Force transitions
    from the C-130H Hercules to the C-130J Super Hercules, O&S costs
    on the C-130H Hercules have decreased, mainly due to a reduced
    fleet size as a result of aircraft retirements, according to program
    officials.
The trends in maintenance costs also varied by aircraft, either increasing,
remaining consistent, or decreasing, as detailed below:

•   Increased: Twenty-five aircraft in our review experienced increasing
    maintenance costs since fiscal year 2011, including the MV-22B
    Osprey (Marine Corps), the E-8C Joint Surveillance Target Attack
    Radar System (Air Force), and the F-22 Raptor (Air Force). For
    example, maintenance costs on the MV-22B Osprey (Marine Corps)
    increased from $412.1 million in fiscal year 2011 to $835.6 million in
    fiscal year 2018, largely due to the increase in the number of aircraft.

27For this report, we are defining “consistent” as being within 5 percent or less of the
original costs.




Page 16                                          GAO-21-101SP Weapon System Sustainment
    In addition, maintenance costs for the E-8C Joint Surveillance Target
    Attack Radar System (Air Force) increased from $274.94 million in
    fiscal year 2011 to $734.96 million in fiscal year 2018, due to
    increases in the cost of depot maintenance as a result of the age of
    the aircraft and the current depot maintenance plan, among other
    reasons, according to officials. Maintenance costs for the F-22 Raptor
    (Air Force) also increased, primarily due to increased contractor
    support costs and repairs to the low-observable coating, from $1.04
    billion in fiscal year 2011 to $1.59 billion in fiscal year 2018.
•   Consistent: Four aircraft that we reviewed had consistent
    maintenance costs, with maintenance costs in fiscal year 2018 that
    were within 5 percent or less of the maintenance costs in fiscal year
    2011. For example, the maintenance costs for the EP-3E Aries II were
    $44.51 million in fiscal year 2011 and $45.87 million in fiscal year
    2018.
•   Decreased: Sixteen aircraft in our review experienced decreases in
    maintenance costs. For example, the A-10 Thunderbolt II (Air Force)
    maintenance costs decreased from $604.45 million in fiscal year 2011
    to $478.52 million in fiscal year 2018 as the number of active A-10
    aircraft have decreased, as part of the Air Force’s efforts to retire the
    A-10. In addition, the maintenance costs for the E-2C Hawkeye
    (Navy) decreased from $241.97 million in fiscal year 2011 to $135.91
    million in fiscal year 2018 as the Navy transitions to using the E-2D
    Advanced Hawkeye.
We also analyzed the O&S costs on a per aircraft basis to account for
differences in the fleet size of various aircraft types. We found that fiscal
year 2018 per aircraft O&S costs also varied across platforms, as shown
in figure 5.




Page 17                                 GAO-21-101SP Weapon System Sustainment
Figure 3: Annual Operating and Support Costs per Aircraft for Selected Department of Defense Aircraft, Fiscal Year 2018




                                         a
                                          We obtained fiscal year 2018 operating and support (O&S) cost data from the Army, but we learned
                                         from the Army that the data were inaccurate. Thus, the costs presented here for the Army aircraft are
                                         based on fiscal year 2017 O&S data.




                                         Page 18                                              GAO-21-101SP Weapon System Sustainment
                     This section contains 43 Sustainment Quick Looks that provide
Sustainment Quick    information on 46 types of DOD aircraft. Some of the Quick Looks cover
Looks for Selected   multiple aircraft that are similar but have separate goals and are reported
                     separately by DOD and the military services. These Quick Looks are
DOD Aircraft         broken out into the following mission areas of aircraft: air refueling, anti-
                     submarine, bomber, cargo, command and control, fighter, and rotary.

                     Each Sustainment Quick Look presents information and data on the life
                     cycle, sustainment strategy, availability and condition, O&S costs, and
                     sustainment challenges for the aircraft. To develop these Quick Looks,
                     we collected information and data on each aircraft from the program
                     offices and the military departments, obtained and reviewed agency
                     documents, and interviewed program and military department officials.
                     See the next page for an illustration of the layout of each Sustainment
                     Quick Look.




                     Page 19                                 GAO-21-101SP Weapon System Sustainment
Page 20   GAO-21-101SP Weapon System Sustainment
Page 21   GAO-21-101SP Weapon System Sustainment
                                    KC-130T Sustainment Quick Look
                                    Common Name: KC-130T
                                    Lead Services: Navy and Marine Corps

                                    Background
Program Essentials                  The KC-130T provides tactical transport of troops and cargo, air-to-air
                                    refueling, aerial delivery, emergency re-supply into or medical evacuation
Manufacturer: Lockheed Martin
                                    from unimproved landing zones, emergency evacuation of personnel and key
Sustainment: Depot maintenance      equipment, battlefield illumination, multisensor image reconnaissance and
conducted at Air Logistic Complex   close air support. Lockheed Martin first manufactured the aircraft in 1982 and
at Ogden, Utah and field            the Navy and Marine Corps plan on operating it beyond 2060.
maintenance conducted by Navy
maintainers                         Life Cycle of the KC-130T

Program Office: Program
Manager – Air 207, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 29.68 years
                                    Overview
Average lifetime flying hours:
9,193 hours per aircraft            The KC-130T fleet did not meet its annual mission capable goals from fiscal
                                    years 2011-2019 and its mission capable rate decreased during the time
Depot maintenance activity          period. According to program officials, the mission capable rate decreased
and squadron locations:             mostly due to issues concerning its propellers, which resulted in a fatal
                                    accident in fiscal year 2017. Total operating and support (O&S) costs also
                                    decreased from about $154.26 million in fiscal year 2011 to about $118.02
                                    million in fiscal year 2018. Specifically, costs for unit-level manpower, unit
                                    operations, and maintenance decreased because, according to officials, of
                                    reductions in the KC-130T aircraft inventory. In fiscal year 2018, maintenance
                                    costs per aircraft accounted for more than one-third of the total O&S costs
                                    per aircraft.

                                    KC-130T Sustainment Status




Sustainment Challenges
and Mitigation Actions
The KC-130T is an aging aircraft
with both maintenance and supply
challenges. Planned actions to
mitigate these challenges include
modernization initiatives to
upgrade the aircraft and an
obsolescence program to procure
hardware and software
components.


Page 22                                                                     GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The KC-130T is a variant of the C-130 airframe. Both systems have similar hardware and software
   configurations and share costs for development of common capabilities and a common product support
   infrastructure. Depot maintenance for the KC-130T is conducted at Air Logistics Complex at Ogden, Utah, and
   Navy and Marine Corps personnel conduct field maintenance on the KC-130T.

•   In a statement to Congress, the Navy stated that the KC-130T modernization initiatives include upgrading the
    propeller system by replacing the legacy four-blade system with an eight-blade, high-thrust composite blade
    system, among other initiatives. The Navy anticipates that all aircraft will be fully modified by the end of fiscal
    year 2020. The Navy is also modernizing the KC-130T brake system with carbon brakes designed to provide
    enhanced safety and maintainability at a reduced weight over the current steel brake assemblies. The Navy’s
    initiatives will reduce maintenance, sustainment, and fuel costs. The Navy plans to complete the installation of
    the modernized brake system by the end of fiscal year 2020. Additionally, according to officials, they are
    planning to replace the center wing box beginning in 2025 to extend the service of the aircraft beyond 2060.

•   In 2018, the Navy implemented an Avionics Obsolescence Upgrade Program for the C-130T, which, according
    to program officials, could also benefit the KC-130T. Specifically, Navy and Marine Corps officials told us that
    obsolete parts from the C-130T modifications will be used to support the KC-130T, as the program office
    continues to pursue funding for KC-130T modifications. The Navy’s Avionics Obsolescence Upgrade program
    also incorporates multiple aircraft improvements to increase aircrew and passenger safety, such as an improved
    aircraft avoidance and awareness system and a digital flight data recorder.


 Availability and Condition
From fiscal year 2011 through fiscal year 2019, the KC-130T fleet fell short of its mission capable goals each year
and the mission capable rate decreased during the nine-year time period. According to officials, the Navy grounded
the fleet in fiscal year 2017 after a fatal accident caused by a propeller malfunction. To expedite the fleet returning to
flight, the Air Force, which is the source of supply for propellers for the family of C-130 aircraft, prioritized propellers
needed for Navy and Marine Corps aircraft. This helped to increase the mission capable rate at the end of fiscal
year 2018 and through fiscal year 2019.

From fiscal year 2011 through fiscal year 2019, the KC-130T’s not mission capable maintenance (NMCM) and not
mission capable supply rates generally increased. According to officials, aircraft awaiting delivery of new propellers
were a contributing factor to the rate increases after a fiscal year 2017 fatal accident, caused by a propeller
malfunction. As new propellers were delivered, the NMCM rate decreased. Specific details on mission capable and
not mission capable rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the KC-130T’s total O&S costs generally decreased from about
$154.26 million to about $118.02 million. Maintenance costs, which also decreased during this period, accounted for
the largest share of O&S costs, averaging about $53.46 million per year, or 39 percent of total O&S costs. According
to officials, these decreases can be attributed to a reduction in aircraft inventory––from 28 in fiscal year 2011 to 17
in fiscal year 2018. Depot maintenance was the most significant category of maintenance costs, averaging about
$20.99 million per year, or 39 percent of the total maintenance costs from fiscal years 2011 through 2018. Other
maintenance costs accounted for the smallest share of maintenance costs during the same time period, averaging
about $1.10 million per year, or 1 percent of the total maintenance costs.




Page 23                                                                             GAO-21-101SP Weapon System Sustainment
KC-130T Total Operating and Support Costs




From fiscal years 2011 through 2018, the KC-130T’s O&S costs per aircraft generally increased from about $5.51
million to about $6.94 million. According to officials, the increase in fiscal year 2018 can be attributed to replacing
the propellers on the aircraft. Maintenance costs per aircraft remained steady, averaging about $2.37 million per
year, and accounted for more than one-third of the total cost per aircraft. Additionally, the number of KC-130T
aircraft decreased from 28 in fiscal year 2011 to 17 in fiscal year 2018. According to officials, this decrease was
because the Navy and Marine Corps are transitioning the aircraft out of service to replace it with the KC-130J.




Page 24                                                                            GAO-21-101SP Weapon System Sustainment
KC-130T Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: The Navy and Marine Corps have operated the KC-130T for close to 40 years and, according to officials,
have implemented a series of modifications to replace or enhance aging components. The Navy and Marine Corps
updated operating techniques to meet mission and training requirements during this time, which has also driven
modifications to the aircraft. In its testimony to Congress, the Navy stated it has several planned modernization
initiatives to update systems and parts to extend the life of the aircraft, such as modifications to the propeller.

Maintenance: As the KC-130T has aged, it has required additional maintenance for repairs that were not originally
planned, such as repairs to the propeller system. Navy and Marine Corps officials told us that maintenance for the
aircraft is also taking longer because more parts need to be repaired and replaced. Therefore, the Navy’s and
Marine Corps’ ongoing and planned actions to mitigate these challenges include maintenance initiatives, such as
scheduling maintenance for components based on forecasted failure rates for those components, and updating
technical publications and training tasks to ensure that training is consistent with the maintenance tasks necessary
to support the aircraft. Also, the Navy and Marine Corps are pursuing an automated system that will store interactive
electronic technical manuals allowing for quicker updates and provide maintainers with step-by-step instructions on
repairing components on the aircraft.

Supply Support: The KC-30T is experiencing some shortages of parts because, according to officials, the size of
the fleet causes very low demand, resulting in items not being ordered and available in stock. The Navy and Marine
Corps’ planned actions to mitigate these challenges include initiatives, such as the Avionics Obsolescence Program,
to procure avionics software with associated, commercially-available hardware through existing government
contracts, and integrating avionics software and associated components into the aircraft to update these systems
and components. Also, according to officials, the Navy and Marine Corps is pursuing an automated system that will
capture data from the aircraft and aircrew to allow maintainers to proactively order parts and materials.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 25                                                                        GAO-21-101SP Weapon System Sustainment
                                    KC-130J Super Hercules Sustainment Quick Look
                                    Common Name: KC-130J
                                    Lead Services: Navy and Marine Corps

                                    Background
Program Essentials                  The KC-130J Super Hercules is a multisensor image reconnaissance and
                                    close air support platform that supports expeditionary operations by providing
Manufacturer: Lockheed Martin
                                    air-to-air refueling, rapid ground refueling, logistic support to operating forces,
Sustainment: Depot maintenance      and tactical transportation of personnel and cargo. The KC-130J was first
conducted at Air Force Logistics    manufactured in 1993 as the latest production variant of the C-130 airframe.
Complexes and field maintenance     The Marine Corps is replacing the KC-130T aircraft with the KC-130J.
conducted by Navy and Marine
Corps maintainers                   Life Cycle of the KC-130J

Program Office: Program
Manager – Air 207, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 11.19 years
                                    Overview
Average lifetime flying hours:
5,877 hours per aircraft            The KC-130J fleet’s mission capable rate decreased from fiscal years 2011
                                    through 2019 and the fleet did not meet its mission capable goals any year
Depot maintenance activity          during the time period. The percent of KC-130J aircraft that were not
and squadron locations:             available due to maintenance and supply issues increased during this time
                                    period because of additional maintenance needed on the engines and
                                    electrical systems of the aircraft, according to officials. Total operating and
                                    support (O&S) costs increased, from about $329.07 million in fiscal year
                                    2011 to about $481.22 million in fiscal year 2018. According to officials,
                                    maintenance costs went up because of significant price increases when
                                    supply contracts were renegotiated as the KC-130J transitioned from
                                    contractor logistics support to government-provided (i.e., organic) support. In
                                    fiscal year 2018, maintenance costs per aircraft accounted for more than
                                    one-third of the total O&S costs per aircraft.

                                    KC-130J Sustainment Status




Sustainment Challenges
and Mitigation Actions
The KC-130J faces maintenance
and supply support challenges.
Planned actions to mitigate these
challenges include initiatives
focused on maintenance
management and updates to the
program support package to
reflect the supply and equipment
needs of the aircraft.


Page 26                                                                        GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The KC-130J is a variant of the C-130 airframe developed to replace the KC-130T aircraft. Approximately 80
   percent of the KC-130J airframe and components are common with the legacy C-130T and KC-130T. As such,
   the KC-130J Life-Cycle Sustainment Plan (2019) supports the sustainment strategy of these three weapon
   systems. This plan provides the Navy and Marine Corps with a roadmap for achieving performance
   requirements and minimizing life-cycle costs associated with the aircraft.

•   Civilian personnel perform depot maintenance of the systems and components on the KC-130J at the Air Force
    Logistics Complexes in Warner Robins, Georgia, and Ogden, Utah. Fleet maintenance is performed
    predominantly by Marine Corps military personnel. The Navy entered into a Sustaining Engineering and
    Logistics Support Services contract with Lockheed Martin for system engineering support.


 Availability and Condition
From fiscal years 2011 through 2019, the KC-130J fleet fell short of its mission capable goals each year and the
mission capable rate declined during the nine-year period. According to officials, the KC-130J did not meet its
mission capable goals because more aircraft were in need of age-related repairs and those repairs took longer to
perform.

From fiscal years 2011 through 2019, the KC-130J’s not mission capable maintenance (NMCM) and not mission
capable supply (NMCS) rates generally increased.. According to officials, the increase in the NMCM rate can be
attributed to additional maintenance on the engines and electrical systems of the aircraft. The increase in the NMCS
rate was due to the KC-130J reaching its material support date––the point the Navy decided the system would
transition from contractor logistics support to government-provided (i.e., organic) supply support. As a result of this
transition, the Navy renegotiated a number of the supply contracts, which caused the supply issues that the Navy is
in the process of resolving. Specific details on mission capable and not mission capable rates were omitted because
the information was deemed by DOD to be sensitive.


 Operating and Support Costs
For fiscal years 2011 through 2018, the KC-130J’s total O&S costs generally increased from about $329.07 million
to about $481.22 million. According to officials, the increase can be attributed to an increase in the number of
aircraft––from 43 in fiscal year 2011 to 51 in fiscal year 2018––and the costs of standing up new squadrons for the
new aircraft. Maintenance costs, which doubled during this time frame, accounted for the largest share of O&S costs
during the time period, averaging about $134.29 million per year, or 37 percent of total O&S costs. According to
officials, maintenance costs increased because of significant price increases when the KC-130J reached its materiel
support date in 2017––the date it was required to transition from contractor logistics support to organic (government-
provided) supply support. As a result of this transition, the Navy renegotiated a number of the supply contracts,
resulting in some cost increases. Depot maintenance was the most significant category of maintenance costs,
averaging about $74.48 million per year, or 55 percent of the total maintenance costs, from fiscal years 2011
through 2018. According to officials, depot maintenance costs doubled from fiscal year 2016 to fiscal year 2017 for
several reasons, including a significant increase in engine repairs, several engines in need of additional repairs, as
well as an increased costs for normal repairs and overhauls.




Page 27                                                                         GAO-21-101SP Weapon System Sustainment
KC-130J Total Operating and Support Costs




From fiscal years 2011 through 2018, the KC-130J’s O&S costs per aircraft generally increased from about $7.65
million to about $9.44 million. Also, maintenance costs per aircraft almost doubled, from about $2.40 million to about
$4.09 million and, on average, accounted for more than one-third of the total costs per aircraft. According to
program officials, these increases can be attributed to the increase in costs related to continuing systems
improvements and maintenance for purchasing and installing modification kits to upgrade the transponder and laser
systems on the aircraft. Additionally, the number of aircraft increased––from 43 aircraft in fiscal year 2011 to 51
aircraft in fiscal year 2018––because the aircraft is still in production, with an anticipated total inventory of 111
aircraft.




Page 28                                                                         GAO-21-101SP Weapon System Sustainment
KC-130J Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: The KC-130J shares similar hardware and software configurations as the C-130 airframe. As such, these
aircraft share similar challenges and, according to program officials, have undergone a series of modifications to
replace or enhance aging components. Navy and Marine Corps officials told us that they have updated operating
techniques to meet mission and training requirements during this time, which has also driven modifications to the
aircraft. Additionally, the Navy and Marine Corps have several planned modernization initiatives to update systems
and parts to extend the life of the aircraft, such as modifications to the propeller.

Maintenance: Navy and Marine Corps officials told us that when they procured the KC-130J, the original equipment
manufacturer was responsible for sustaining the aircraft. However, when the aircraft transitioned to organic
sustainment, the Navy and Marine Corps were unable to obtain the technical data of the aircraft, which would allow
the Navy and Marine Corps to update the sustainment strategy of the aircraft as it matures. Also, the lack of the
technical data compromises the Navy’s and Marine Corps’ ability to analyze and resolve sustainment issues related
to the KC-130J. According to Navy and Marine Corps officials, current actions to mitigate these challenges include
updating technical publications and training tasks to ensure that training is consistent with the maintenance tasks
necessary to support the aircraft, and implementing maintenance initiatives to improve the maintenance
management to ensure the maintenance conducted addresses the current state of the aircraft. The Navy and
Marine Corps are also pursuing an automated system that will store interactive electronic technical manuals
allowing for quicker updates, and provide maintainers with step-by-step instructions on repairing components on the
aircraft.

Supply Support: Navy and Marine Corps officials told us the KC-130J has experienced supply issues because the
Navy and Marine Corps did not update the analysis needed to support the supply requirements of the aircraft when
it was procured. As such, demand for parts given military usage has resulted in some shortages, as the Navy did not
adequately plan for the parts that the aircraft would need for maintenance and repairs. According to program
officials, planned actions to mitigate these challenges include collecting data and developing metrics to focus on
necessary critical repair parts and updating the program support package to reflect the supply and equipment needs
of the aircraft.




Page 29                                                                       GAO-21-101SP Weapon System Sustainment
 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 30                                                                     GAO-21-101SP Weapon System Sustainment
                                     KC-10 Extender Sustainment Quick Look
                                     Common Name: KC-10
                                     Lead Service: Air Force

                                     Background
Program Essentials                   The KC-10 Extender is a tanker and cargo aircraft that can refuel aircraft and
                                     transport support personnel and equipment on overseas deployments. The
Manufacturer: Boeing
                                     KC-10 is also capable of transporting ambulatory patients during aeromedical
Sustainment: Depot maintenance       evacuations. It was first manufactured in 1981 and was declared fully
performed by a contractor            operational in 1988.
(HAECO Americas Special
Services) and field support by Air   Life Cycle of the KC-10
Force personnel
Program Office: Tinker Air Force
Base, Oklahoma
Fiscal Year 2019 Data
Average age: 34 years
Average lifetime flying hours:
                                     Overview
32,482 hours per aircraft
                                     The KC-10 fleet did not meet its aircraft availability goals for any year from
Depot maintenance activity           fiscal year 2011 through fiscal year 2019, but met or exceeded its mission
and squadron locations:              capable goals for 3 of the 9 fiscal years. The KC-10’s aircraft availability rate
                                     increased slightly and its mission capable rate stayed about the same during
                                     the time period. Total operating and support (O&S) costs for the KC-10 fleet
                                     decreased from about $1.49 billion in fiscal year 2011, to about $991.71
                                     million in fiscal year 2018 due in part to about a 51 percent decrease in unit
                                     operations costs over this period. During this same time period, the annual
                                     O&S costs per aircraft decreased from $25.28 million to $16.81 million.
                                     Further, in fiscal year 2018, maintenance costs per aircraft accounted for
                                     nearly 42 percent of the total O&S costs per aircraft.

                                     KC-10 Sustainment Status




Sustainment Challenges
and Mitigation Actions
The KC-10 faces maintenance and
supply support challenges.
Planned actions to mitigate these
challenges include replacing and
resealing various fuel system
components, replacing the engine
driven pumps on the aircraft, and
overhauling the existing stock of
reparable items.




Page 31                                                                        GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The revised KC-10 life-cycle sustainment plan is expected to be issued in the third quarter of fiscal year 2020,
   according to program officials. This plan will establish the approaches and guidance to manage and control the
   life-cycle product support efforts.

•   Sustainment of the KC-10 is currently performed through contractor logistics support (CLS) contracts, according
    to program officials. The KC-10, which retains 88 percent of systems commonality with the Boeing DC-10
    aircraft, maintains Federal Aviation Administration certification and uses commercial parts and practices to the
    maximum extent possible. The airframe CLS contract, according to the KC-10 program office, includes all
    actions required for sustaining the aircraft subsystems, supply support, logistics integration and support, and
    aircraft maintenance and modifications. According to officials, the KC-10 engine CLS contract provides all tasks
    necessary to maintain and support the engine, including parts and logistics, teardown, overhaul, and on-wing
    support/contract field teams.


 Availability and Condition
The KC-10 fleet did not meet its aircraft availability goals for any year from fiscal year 2011 through fiscal year 2019,
but met or exceeded its mission capable goals for 3 of the 9 fiscal years during that period. The KC-10’s aircraft
availability rate in fiscal year 2019 was slightly higher than it was in fiscal year 2011, and its mission capable rate
was almost the same as it was in fiscal year 2011.Program officials said the KC-10’s availability rate was driven by
the large amount of time required to perform maintenance on its fuel systems in the field and in depot.

From fiscal year 2011 through fiscal year 2019, the KC-10’s not mission capable rates fluctuated. In fiscal year
2019, the not mission capable supply (NMCS) and the not mission capable both (NMCB) maintenance and supply
rates were slightly lower than they were in fiscal year 2011, and the not mission capable for maintenance (NMCM)
rate was slightly above its fiscal year 2011 level. Program officials stated that maintenance on the KC-10’s fuel
systems accounted for about a third of the NMCM rate and the fuel system was the highest driver of the NMCS and
NMCM rates in fiscal years 2018 and 2019. Specific details on aircraft availability, mission capable and not mission
capable rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
Total O&S costs for the KC-10 fleet generally decreased from approximately $1.49 billion in fiscal year 2011 to
$991.71 million in fiscal year 2018. The largest decreases during these years were in unit operations and
maintenance. Program officials stated that they do not manage these costs and therefore were not sure why they
decreased. However, according to officials, the KC-10 flight management system modification, which was started in
fical year 2015 and completed in fiscal year 2017, caused a substantial increase in continuing system improvements
and indirect support costs. Also, officials stated the transition in fiscal year 2017 from one all-encompassing contract
to two separate contracts to manage depot and supply chain operations caused an incease in contractor logistics
support costs for that year, but later resulted in some cost savings in fiscal year 2018.




Page 32                                                                           GAO-21-101SP Weapon System Sustainment
KC-10 Total Operating and Support Costs




While the total number of aircraft in the KC-10 fleet remained constant from fiscal years 2011 through 2018, the total
O&S costs per aircraft generally decreased. Specifically, the annual O&S costs per aircraft decreased from $25.28
million to $16.81 million during this time period. Maintenance costs per aircraft also decreased from $8.37 million to
$6.99 million during the same timeframe, with an increase in these costs from fiscal year 2015 through fiscal year
2017, when the O&S costs per aircraft was at its highest of $8.96 million. In addition, the KC-10 mission capable
and aircraft availability rates slightly dropped in fiscal year 2018 from early highs, as discussed above.




Page 33                                                                         GAO-21-101SP Weapon System Sustainment
KC-10 Operating and Support Costs per Aircraft and Fleet Size




 Sustainment Challenges and Mitigation Actions
Maintenance: According to program officials, the KC-10 fuel system is the key factor that affects aircraft availability.
To mitigate issues with the fuel system, the program office executed an Aircraft Availability Improvement Program
that includes initiatives to improve the fuel system, such as replacing the fuel storage bladders located inside of the
fuel tanks and resealing the auxiliary fuel tanks during scheduled depot maintenance. Program officials stated that
these initiatives are 83 percent complete—replaced on 49 of the 59 KC-10 aircraft since started in fiscal year 2017.
The remaining replacements are scheduled to be completed in fiscal year 2020.

Supply Support: The KC-10 also has supply challenges. For example, according to program officials, in December
2017, when multiple radomes—dome-shaped structures that protect radar equipment—were removed and replaced
during scheduled maintenance, the supply system was strained due to an increased need for new radomes. To
address this challenge, program officials increased the overall supply of new radomes to help with this higher
demand. According to officials, there are challenges associated with the KC-10 contractor logistics support contract,
most recently awarded in July 2016 and recompeted every 8 to 10 years. While officials anticipate that the current
contractor will have some learning curve challenges in the early years as a new contractor, they expect peak
performance in the mid years of the contract before a slight downward turn in performance toward the end of the
contract in 2025, due to fewer performance incentives in the later contract years.
Further, program officials stated that about $20 million were taken from the KC-10 program in fiscal year 2019 to
help certain fighter aircraft meet the Secretary of Defense’s 80 percent mission capable goal for these aircraft, which
has caused the KC-10 total not mission capable for supply rates to rise slightly in fiscal year 2019.

 Program Office Comments
In commenting on a draft of this assessment, the program office noted that both the engine and airframe CLS
contracts have moved through the transition phase into full performance. It also noted that the KC-10 contractors
performed well throughout fiscal year 2019, with total not mission capable for supply staying below 5 percent and
the war readiness engine metric staying above the six engines required. Officials also stated that in fiscal year 2019,
the KC-10 Aircraft Availability Improvement Program initiatives were temporarily suspended because of
unscheduled depot work to repair fuel leaks and perform major structural repairs; however, they project improved
aircraft availability in fiscal year 2020. In addition, the program office provided technical comments which we
incorporated where appropriate.



Page 34                                                                           GAO-21-101SP Weapon System Sustainment
                                      KC-135 Stratotanker Sustainment Quick Look
                                      Common Name: KC-135
                                      Lead Service: Air Force

                                      Background
Program Essentials                    The KC-135 Stratotanker was first manufactured in 1954. The aircraft is the
                                      Air Force’s primary aerial refueling tanker and also provides aerial refueling
Manufacturer: Boeing
                                      support to Navy, Marine Corps, and allied nation aircraft. The KC-135 is also
Sustainment: Depot maintenance        capable of transporting litter and ambulatory patients using patient support
conducted at the Oklahoma Air         pallets during aeromedical evacuations.
Logistics Complex, Oklahoma
                                      Life Cycle of the KC-135
Program Office: Tinker Air Force
Base, Oklahoma
Fiscal Year 2019 Data
Average age: 58 years
Average lifetime flying hours:
24,372 hours per aircraft
Depot maintenance activity            Overview
and squadron locations:               The KC-135 fleet did not meet its aircraft availability goals form fiscal years
                                      2011 through 2019, but was above its mission capable goals in 3 of the 9
                                      fiscal years. The KC-135’s aircraft availability and mission capable rates
                                      decreased during the time period. Total operating and support (O&S) costs
                                      for the KC-135 fleet remained fairly consistent—ranging from about $4.13
                                      billion to about $4.63 billion—from fiscal years 2011 through 2018. While
                                      maintenance costs steadily increased over this time period and maintenance
                                      was the largest cost category in fiscal year 2018, unit operations costs
                                      decreased. Depot maintenance costs were the largest driver of the
                                      maintenance cost increases. The KC-135 fleet decreased by 18 aircraft from
                                      416 to 398 during the time period; however, total O&S costs per aircraft
                                      remained fairly constant. In fiscal year 2018, the O&S costs per aircraft were
                                      about $10.65 million, with about $4.61 million per aircraft (or 43 percent)
                                      dedicated to maintenance issues.

                                      KC-135 Sustainment Status
Sustainment Challenges
and Mitigation Actions
The KC-135 faces challenges with
corrosion and parts obsolescence.
Planned actions to mitigate these
challenges include executing
additional maintenance tasks for
known corrosion problem areas,
identifying alternative parts, and
prioritizing aircraft for repair to
support the most critical missions,
among others.




Page 35                                                                        GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The Air Force issued the KC-135 Life-Cycle Sustainment Plan in August 2017. The plan establishes the
   methodologies and guidance to manage and control life-cycle product support efforts.

•   The Air Force sustains the KC-135 fleet through programmed depot maintenance, which is generally performed
    on a 5-year cycle.

•   Programmed depot maintenance of the KC-135 is conducted by the Air Force at the Oklahoma Air Logistics
    Complex, Oklahoma. The majority of supply support for the KC-135 is provided by the Air Force Sustainment
    Center and the Defense Logistics Agency.


 Availability and Condition
The KC-135 fleet did not meet its aircraft availability goals for any year from fiscal year 2011 through fiscal year
2019. During this time the availability rate only decreased slightly, and the fleet was above its mission capable goals
for 3 of the 9 years. According to program officials, the decline in the aircraft availability rate was due to increasing
field maintenance downtime as well as depot inductions for a modification to convert the last of the analog cockpit
avionics to digital. Additionally, officials stated that increased field maintenance downtime and depot inductions were
a part of the reason for the decline in the KC-135 mission capable rate.

From fiscal years 2011 through 2019, the KC-135’s rates increased slightly for not mission capable maintenance
(NMCM), not mission capable supply, and not mission capable both maintenance and supply. The largest driver of
the decrease in the mission capable rate was maintenance. Program officials said that increase in the NMCM rate
was primarily due to field maintenance downtime related to several key areas, including fuel leaks, unreliable
avionics instruments, and structural corrosion. Program officials also said that an Aircraft Availability Improvement
Program was developed for fiscal years 2019 through 2024 that includes 16 initiatives that are expected to improve
the aircraft availability and mission capable rates. The KC-135’s improvement program includes initiatives to replace
fuel bladders, upgrade avionics, and optimize inspection intervals, among other improvements. Specific details on
aircraft availability, mission capable and not mission capable rates were omitted because the information was
deemed by DOD to be sensitive.


 Operating and Support Costs
For fiscal years 2011 through 2018, the total O&S costs for the KC-135 fleet remained fairly constant, ranging from
about $4.13 billion to about $4.63 billion. However, maintenance costs increased during the time period while unit
operations costs decreased. In fiscal year 2018, maintenance was the largest O&S cost category, and depot
maintenance was the largest driver of the increase in maintenance costs over the time period. Program officials
stated that depot maintenance costs grew because of increased requirements associated with aging aircraft, which
required additional tasks during programmed depot maintenance.




Page 36                                                                           GAO-21-101SP Weapon System Sustainment
KC-135 Total Operating and Support Costs




From fiscal years 2011 through 2018, the KC-135 fleet decreased by 18 aircraft, from 416 to 398 aircraft, and total
O&S costs per aircraft remained fairly constant. More specifically, the annual O&S costs per aircraft only varied
between a low of about $10.26 million and a high of $11.41 million. However, maintenance costs per aircraft climbed
steadily, from $3.16 million to $4.61 million during the same timeframe. In addition, the mission capable and aircraft
availability rates slightly dropped from earlier highs, as discussed previously.




Page 37                                                                         GAO-21-101SP Weapon System Sustainment
KC-135 Operating and Support Costs per Aircraft and Fleet Size




 Sustainment Challenges and Mitigation Actions
Maintenance and an Aging Aircraft: According to Air Force officials, as the KC-135 continues to age, the number
of maintenance hours related to corrosion has increased, and this has become the largest maintenance challenge.
KC-135 program officials stated they have established recurring maintenance tasks to address known problem
areas and reduce aircraft downtime. These tasks include maintenance actions varying from minor rework in some
areas to complete component replacement in other areas. In addition, officials said that two previously-established
programs are part of the KC-135 program office’s mitigation efforts: the Aircraft Structural Integrity Program and the
Corrosion Prevention and Control Program. The goal of these programs, in conjunction with the KC-135 Structures
Working Group, is to continuously monitor the aircraft and to identify and define the requirements for future
inspections and maintenance actions.

Supply Support and an Aging Aircraft: Air Force officials also told us that the vast majority of supply support
issues stem from decreased asset availability as a result of insufficient organic (i.e., government-owned and
operated) and contract repair sources, obsolescence issues, and increased failures directly related to aging of the
aircraft. The KC-135 program office stated that it works with the supply chain and engineering organizations to
develop mitigation strategies that will minimize the impact to the aircraft. This includes negotiating alternative repair
schedules, identifying alternate parts, prioritizing aircraft to ensure the most critical missions are supported first,
utilizing assets from the Aerospace Maintenance and Regeneration Group, and allowing reuse of some parts, if
appropriate. The combination of these efforts enables the KC-135 to continue to fly missions and minimizes impacts
to the fleet, according to program officials.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate. According to program officials, aggressive strategic management continues to keep
the KC-135 available as the nation’s backbone for air refueling. Further, a robust aircraft availability improvement
program has stemmed the aircraft’s decreased availability. Program officials forecast that it will increase availability
throughout the next decade through a combination of process improvements, sustainment technology advances and
continuous materiel product upgrades.




Page 38                                                                           GAO-21-101SP Weapon System Sustainment
Page 39   GAO-21-101SP Weapon System Sustainment
                                      EP-3E Aries II Sustainment Quick Look
                                      Common Name: EP-3E
                                      Lead Service: Navy

                                      Background
Program Essentials                    The EP-3E Aries II is a land-based, multi-intelligence reconnaissance aircraft
                                      that was first manufactured in 1969. The EP-3E is the Navy’s only land-
Manufacturer: Lockheed Martin
                                      based reconnaissance aircraft that provides fleet and theater commanders
Sustainment: Depot maintenance        worldwide with near real-time tactical intelligence. The EP-3E uses sensitive
conducted by contractor support       receivers and high-gain dish antennas to exploit a wide range of electronic
and Navy personnel                    emissions from deep within targeted territory. This information can be used
                                      for information dominance, battle space situational awareness, and anti-
Program Office: Program               submarine warfare applications.
Manager – Air 290, Naval Air
Systems Command, Patuxent             Life Cycle of the EP-3E
River, Maryland
Fiscal Year 2019 Data
Average age: 42.19 years
Average lifetime flying hours:
22,405.3 hours
Depot maintenance activity
and squadron locations:               Overview
                                      From fiscal years 2011 through 2019, the EP-3E fleet met or exceeded its
                                      mission capable goals in 7 of the 9 years and its mission capable rate
                                      increased slightly. Total operating and support (O&S) costs were about
                                      $150.33 million in fiscal year 2018, with about $45.87 million (31 percent)
                                      spent on maintenance. O&S costs have decreased since fiscal year 2011,
                                      when these costs were $308.38 million. According to program officials, this
                                      decrease was due to avionics upgrades that increased the reliability of the
                                      aircraft and therefore reduced costs. Total O&S costs per aircraft was $12.53
                                      million in fiscal year 2018, a decrease from fiscal year 2011.

                                      EP-3E Sustainment Status




Sustainment Challenges
and Mitigation Actions
The EP-3E faces challenges
related to corrosion, maintenance
training, and diminishing supply of
needed parts. The program office
is increasing corrosion prevention
actions at the squadrons, working
with the Navy to offer additional
training on EP-3 maintenance, and
working to address supply
shortages.




Page 40                                                                       GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The EP-3 has a Life-Cycle Support Plan for the aircraft’s Joint Signals Intelligence Airborne Family
   Modernization Common Configuration Program. The Navy published the plan in 2011 and established and
   defined acquisitions logistics support functions and requirements for this modernization program.

•   The Navy sustains the EP-3E fleet through organizational and depot maintenance. According to program office
    officials, depot maintenance cycles are determined yearly, based on the previous year’s depot sustainment
    events and analysis of individual aircraft. Programmed depot maintenance is conducted by a combination of
    contractor support (Lockheed Martin) and Navy personnel at the Fleet Readiness Center Southeast in
    Jacksonville, Florida or at Lockheed Martin’s facility in Greenville, South Carolina.

•   The supply chain for the EP-3E is managed by the Naval Supply Systems Command Weapon Systems Support
    in Philadelphia, Pennsylvania and by the program office.


 Availability and Condition
The EP-3E fleet met or exceeded its mission capable goals in 7 of the 9 years from fiscal year 2011 through fiscal
year 2019. Over this time period, its mission capable rate increased slightly. According to program officials, this
increase in the mission capable rate was partially due to efforts to improve the reliability of the legacy electronic
intelligence system, which facilitates the collection of radar and other high frequency signals. The officials explained
that the Navy began replacing this system in September 2018 with final completion scheduled in 2020. The mission
capable rate also increased because the program office completed several other efforts during fiscal year 2018 to
mitigate diminishing manufacturing sources and material shortages, according to the program officials.

From fiscal years 2011 through 2019, the not mission capable maintenance (NMCM) rate decreased slightly and the
not mission capable supply rate increased slightly. The NMCM rate was the largest driver of the EP-3E’s mission
capable rate during the time period. Specific details on mission capable and not mission capable rates were omitted
because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal years 2011 through 2018, the EP-3E’s total O&S costs decreased significantly, from $308.38 million in
2011 to $150.33 million in 2018. During that time, the number of aircraft also decreased, from 16 in fiscal year 2011
to 12 in fiscal year 2018, which contributed to the decrease in total O&S costs. However, according to program
officials, the decreases in total O&S costs can partially be explained by upgrades to the avionics systems, which
resulted in less money spent on continuing system improvements. Maintenance costs varied over this time period,
but fiscal year 2011 and 2018 costs were about the same, with $44.51 million spent on maintenance in fiscal year
2011 and $45.87 million spent on maintenance during fiscal year 2018. Since the total O&S costs decreased,
maintenance costs increased as a percentage of the total, from 14 percent in fiscal year 2011 to 31 percent in fiscal
year 2018.




Page 41                                                                           GAO-21-101SP Weapon System Sustainment
EP-3E Total Operating and Support Costs




From fiscal years 2011 through 2018, the EP-3E’s O&S costs per aircraft decreased from $19.27 million to $12.53
million, while the mission capable rate also decreased. However, during this same time period, maintenance costs
per aircraft increased from $2.78 million to $3.82 million due to increases in contractor support costs, according to
program officials.




Page 42                                                                          GAO-21-101SP Weapon System Sustainment
EP-3E Operating Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Maintenance: Program officials cited several challenges in sustainment of the EP-3E. First, corrosion is a major
challenge, which the officials stated is being addressed through increased prevention efforts at the squadron level
and additional planned depot sustainment events. Second, program officials cited the need for additional operator
and maintenance training and stated that they are working with the Navy’s training organizations to provide
additional maintenance training courses to improve maintainer efficiency. Finally, program officials stated that
sustaining the aircraft’s information assurance and communication security systems has been challenging, and that
the program office has issued improved instructions to assist with maintenance.

Supply Support: Program officials stated that diminishing manufacturing sources and material shortages for the
avionics systems beyond 2021 is a concern, and that they are continuously working to address these shortages. In
addition, program officials stated that additional funding may be needed to maintain required readiness levels as the
EP-3E ages.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 43                                                                        GAO-21-101SP Weapon System Sustainment
                                       P-8A Poseidon Sustainment Quick Look
                                       Common Name: P-8A
                                       Lead Service: Navy

                                       Background
Program Essentials                     The P-8A Poseidon is a multimission capable aircraft with maritime, patrol,
                                       and reconnaissance capabilities that was first manufactured in 2009. The P-
Manufacturer: Boeing
                                       8A can operate independently or in conjunction with carrier strike forces and
Sustainment: Depot maintenance         their aircraft, expeditionary strike groups, and other joint and allied assets.
conducted by AAR and Boeing            The P-8A conducts missions such as maritime and littoral surveillance and
with field maintenance conducted       reconnaissance; sea control; targeting and strike support; and command,
by Navy personnel                      control, and communications tasks.

Program Office: Program                Life Cycle of the P-8A
Manager – Air 290, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 3.2 years
Average lifetime flying hours:
2,314 hours per aircraft
                                       Overview
Depot maintenance activity             The P-8A fleet met or exceeded its mission capable goals twice from fiscal
and squadron locations:                year 2013—when the Navy declared initial operational capability—through
                                       fiscal year 2019. Overall, its mission capable rate decreased during this time
                                       period. Total operating and support (O&S) costs increased––from $123.05
                                       million in fiscal year 2013 to $759.46 million in fiscal year 2018––largely
                                       because the operating fleet grew from 14 aircraft in 2013 to 72 in 2018. In
                                       fiscal year 2018, maintenance accounted for about 24 percent of the total
                                       O&S costs and the O&S costs per aircraft was $10.55 million.

                                       P-8A Sustainment Status




Sustainment Challenges
and Mitigation Actions
The main challenge facing the
P-8A is the difficulty of sustaining
a military aircraft that is based on
a commercial design. To address
this issue, the Navy and Boeing
entered into a technical agreement
to obtain needed technical data.




Page 44                                                                         GAO-21-101SP Weapon System Sustainment
Sustainment Strategy
•   The Life-Cycle Sustainment Plan for the P-8A was issued in 2013 and is generally focused on full-rate
    production and acquisition of the P-8A. The plan provides a roadmap toward achieving performance
    requirements and minimizing life-cycle costs. The Navy is currently upgrading the P-8A’s communication, radar,
    and weapons, which will be incorporated into the existing P-8A architecture.

•   According to program officials, sustainment of the fleet is accomplished through programmed depot
    maintenance, performed on a 4-year recurring cycle by contractor personnel at AAR in Indianapolis, Indiana or
    Boeing in Atlanta, Georgia. As the fleet grows, the planned number of depot inductions per year increases. For
    example, program officials told us that eight aircraft are scheduled for depot induction in 2019, while 24 are
    scheduled for 2024.

•   Organizational maintenance support for the P-8A is conducted by Navy personnel, supplemented with a small
    contingent of Navy field service representatives and technical representatives. The P-8A uses a supply chain
    managed through Naval Supply Systems Command and the Defense Logistics Agency.


 Availability and Condition
The P-8A fleet met or exceeded its mission capable goals twice from fiscal year 2013—when the Navy declared
initial operational capability for the P-8A—through fiscal year 2019. Overall, its mission capable rate decreased
during this time period. According to program officials, there were three main not mission capable drivers for the P-
8A: conditional inspections, scheduled inspections, and the turret deployment unit. The program officials explained
that the scheduled inspections were performed based on the Navy’s scheduled maintenance plan. The Navy
developed this plan using commercial data because the P-8A was built on a commercial aircraft frame. However,
the plan has not been adequate for military usage. As the program matures, the officials said that the scheduled
maintenance plan will be updated based on the Navy’s P-8A usage data and the inspections should become more
efficient. In addition, the Forward Turret Deployment Unit—a structure mounted to the aircraft that contains a
rotating camera turret—has had a higher than expected failure rate. The officials told us that they are working to
redesign this component to minimize future failures. Further, they stated that the program office has a plan for
meeting the P-8A fleet’s mission capable goal again by 2021. This plan includes optimizing scheduled maintenance,
converting existing technical manuals into interactive electronic technical manuals, and releasing a structural repair
manual.

From fiscal year 2013 through fiscal year 2019, the P-8A’s rates increased for not mission capable maintenance
(NMCM) and not mission capable supply (NMCS). However, the largest driver of the P-8A mission capable rate was
maintenance during the time period. The NMCM rate increase was primarily due to scheduled inspections, as
discussed above. Program officials also stated that the increase in the size and age of the fleet placed additional
demands on the supply system, causing the NMCS rate to rise during the time period. Specific details on mission
capable and not mission capable rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
Total O&S costs have increased from $123.05 million in fiscal year 2013 to about $759.46 million in fiscal year 2018.
During this time period, the number of aircraft increased from 14 to 72. In fiscal year 2018, maintenance represented
about 24 percent of the total O&S costs, with the majority of the maintenance costs attributed to depot level
reparables. The program office stated that fleet budgets are adequate but that the program is not fully funded for
sustainment operations and maintenance, which could hamper readiness efforts and decrease the mission capable
rate beginning in fiscal year 2021.




Page 45                                                                         GAO-21-101SP Weapon System Sustainment
P-8A Total Operating and Support Costs




As the P-8A fleet size increased from 14 aircraft in fiscal year 2013 to 72 aircraft in fiscal year 2018, total O&S costs
per aircraft increased from $8.79 million to $10.55 million. This increase occurred largely due to the increase in
maintenance costs, including consumable materials and repair parts, depot-level reparables, depot maintenance,
and intermediate maintenance. During this same time period, the mission capable rate fell from 80 percent in fiscal
year 2013 to 63 percent in fiscal year 2018.




Page 46                                                                           GAO-21-101SP Weapon System Sustainment
P-8A Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Maintenance: The P-8A is a military aircraft based on a commercial design but, according to the program office, is
certified under Navy airworthiness authority and sustained by Navy maintainers. According to the program office,
this arrangement is challenging because technical data needed for maintenance has not been readily available to
the Navy. To address this issue, the Navy recently entered into a technical data agreement with Boeing to obtain the
needed technical data for maintaining the aircraft.

Supply: The Navy has had difficulty procuring parts on the commercial marketplace due to federal and military
requirements for the parts that are not common in the commercial industry. In addition, according to the program
office, the Navy developed initial spare parts requirements based on engineering estimates for predicted failure
rates. As the program has matured, the program office has updated those requirements based on actual fleet
usage. Further, the program office stated that it is actively working with Boeing to improve spare parts deliveries for
the Forward Turret Deployment Unit given the higher than expected failure rates for associated parts.


 Program Office Comments
In commenting on a draft of this assessment, the program office stated that it continues to reassess the P-8A
sustainment posture in order to identify and remove any barriers or constraints and implement opportunities to
improve the overall readiness of the program.




Page 47                                                                          GAO-21-101SP Weapon System Sustainment
Page 48   GAO-21-101SP Weapon System Sustainment
                                      B-1B Lancer Sustainment Quick Look
                                      Common Name: B-1B
                                      Lead Service: Air Force

                                      Background
Program Essentials                    The B-1B is a multimission weapon system that was first manufactured in
                                      1984. It carries the largest conventional payload of both guided and unguided
Manufacturer: Boeing
                                      weapons in the Air Force inventory and can deliver precision and non-
Sustainment: Depot maintenance        precision weapons against adversaries. The B-1B was first used in combat
conducted organically at              support of operations against Iraq during Operation Desert Fox in December
Oklahoma Air Logistics Center,        1998.
Oklahoma
                                      Life Cycle of the B-1B
Program Office: Tinker Air Force
Base, Oklahoma
Fiscal Year 2019 Data
Average age: 31.8 years
Average lifetime flying hours:
9,651.7 hours
Depot maintenance activity            Overview
and squadron locations:               From fiscal years 2011 through 2019, the B-1B fleet did not meet any of
                                      its annual aircraft availability and mission capable goals and its aircraft
                                      availability and mission capable rates decreased. Total operating and
                                      support (O&S) costs decreased since fiscal year 2011, from about $1.84
                                      billion to about $1.13 billion in fiscal year 2018. Further, total O&S costs
                                      per aircraft decreased during the same time period, from $27.95 million in
                                      fiscal year 2011 to $18.20 million in fiscal year 2018. According to
                                      officials, there is no one factor that led to decreasing O&S costs.
                                      However, a review of the costs shows decreasing costs for unit level
                                      operations and maintenance. Further, the B-1B was grounded in 2018
                                      over concerns about ejection seats and in 2019 over concerns about its
                                      egress system.

                                      B-1B Sustainment Status


Sustainment Challenges
and Mitigation Actions
The B-1B faces sustainment
challenges related to its age,
including increased maintenance
needs and difficulty finding
replacement parts. To address
these issues, the Air Force is
making modifications to the
aircraft to extend its service life
and working with the Defense
Logistics Agency to improve parts
availability.




Page 49                                                                       GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The Air Force issued the Life-Cycle Sustainment Plan for the B-1B Lancer in October 2018. This plan describes
   the approach and resources necessary to develop and integrate sustainment requirements into the B-1B’s
   design, development, testing and evaluation, fielding, and operations.

•   The Air Force sustains the B-1B fleet through programmed depot maintenance, which is performed on a 5-year
    cycle. According to the program office, the aircraft also underwent five different modification programs, including
    upgrades to its fuselage and integrated battle station, from 2011 to 2014.

•   Depot maintenance of the B-1B is conducted organically by the Air Force at Oklahoma Air Logistics Complex,
    Oklahoma. The supply chain for the B-1B is managed by the Air Force’s Supply Chain Management Wing.


Availability and Condition
The B-1B fleet did not meet any of its annual aircraft availability and mission capable goals from fiscal year 2011
through fiscal year 2019. Both of the rates decreased during this time period. According to program officials, multiple
factors contributed to the decline in aircraft availability rates, including several modification programs during 2011 to
2014 and specific inspections, repairs, and replacements conducted from 2013 to 2015. These efforts resulted in the
aircraft not being available for operations and training. Program officials also said that an Aircraft Availability
Improvement Plan Tiger Team was established in December 2018 to identify ways for improving overall aircraft
availability. The Tiger Team is working directly with stakeholders at Barksdale Air Force Base, Louisiana; Dyess Air
Force Base, Texas; and Ellsworth Air Force Base, South Dakota to find efficiencies in the B-1B repair processes to
improve availability.

The largest driver of the B-2 fleet’s lower mission capable rate was maintenance; the not mission capable supply
rate and the not mission capable both maintenance and supply rate were both slightly lower in fiscal year 2019 than
in fiscal year 2011. Program officials said that the higher not mission capable maintenance rate was primarily due to
the age of the aircraft, which requires increased inspections and modifications intended to address safety and
performance issues. During these inspections, which can take up to 28 days, the aircraft is not mission capable.
Inspections have discovered cracks on certain aircraft antennas and flight control mechanisms that could potentially
lead to safety-of-flight issues. According to Air Force officials, the Air Force has been working with local
manufacturers to repair these issues. Specific details on mission capable and not mission capable rates were
omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
Total operating and support costs, along with maintenance costs, decreased from fiscal years 2011 to 2018.
Program officials stated that there was no single constant driver that has driven the decrease in O&S total costs and
further stated that without sustaining engineering funding, it will be difficult to keep the B-1B at an adversarial
competitive advantage through modernization efforts. Maintenance and unit level manpower were the largest cost
drivers for the B-1B, with maintenance accounting for about 31 percent of the total cost and unit level manpower
accounting for about 28 percent of the total O&S costs in fiscal year 2018. Within maintenance, the Air Force
experienced a significant decrease in the costs for depot level reparables for the B-1 fleet. According to program
officials, the decrease in depot level reparables costs was due to the decrease in the number of aircraft, from 66 to
62.




Page 50                                                                           GAO-21-101SP Weapon System Sustainment
B-1B Total Operating and Support Costs




Total O&S costs per aircraft decreased from fiscal year 2011 to fiscal year 2018. For example, in fiscal year 2011
the total O&S costs per aircraft was $27.95 million and in fiscal year 2018 it was $18.20 million. Maintenance costs
per aircraft also decreased, from $9.13 million to $5.56 million, during this time period. In addition, the mission
capable and aircraft availability rates slightly dropped, as discussed above.




Page 51                                                                         GAO-21-101SP Weapon System Sustainment
B-1B Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: According to the program office, the B-1B current average age is 31.8 years, which exceeds its original
structural design life of 30 years. The program office further stated that, over time, Air Force inspections have
identified several issues related to the aircraft’s age, including structural issues, such as cracks in the wings.
According to program officials, the B-1B was continuously deployed to South West Asia from 2011 to 2014 in
support of contingency operations, and after returning in 2014, the Secretary of Defense gave a 2-year aircraft
stand-down directive to the fleet to focus on sustaining the aging aircraft.

Maintenance: Program officials stated that the Air Force used the B-1B extensively in South West Asia from 2011
to 2014, causing stress on this aging system. In addition, program officials stated that emerging and unplanned
requirements found during aircraft structural integrity program inspections increased the maintenance hours
necessary to repair the aircraft. For example, during Full Scale Fatigue Testing, structural issues were found on the
fuselage. Actions to address these issues include partial rib replacement and replacement of the forward
intermediate fuselage substructure and skins (i.e., surface of the aircraft).

Supply: According to program officials, additional maintenance requirements were sometimes difficult to address in
the past due to challenges in locating replacement parts for this aging weapon system. To address the shortage in
replacement parts, the program office is working with the Air Logistics Complexes and the Defense Logistics Agency
to improve parts production and availability.


 Program Office Comments
In commentating on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 52                                                                          GAO-21-101SP Weapon System Sustainment
                                     B-2 Spirit Sustainment Quick Look
                                     Common Name: B-2
                                     Lead Service: Air Force

                                     Background
Program Essentials                   The B-2 Spirit is a multirole bomber first manufactured in 1988 and capable
                                     of delivering both conventional and nuclear munitions. The B-2’s low-
Manufacturer: Northrop
                                     observable, or stealth, characteristics give it the ability to penetrate an
Grumman
                                     enemy’s defenses. The B-2 is currently undergoing a modernization process
Sustainment: Depot maintenance       to include upgrades to its targeting, missile, and antenna systems.
is performed by Air Force
personnel, and contractor support    Life Cycle of the B-2
and supply are managed by the
Air Force
Program Office: Wright-Patterson
Air Force Base, Ohio
Fiscal Year 2019 Data
Average age: 25.9 years
                                     Overview
Average lifetime flying hours:
7,247 hours per aircraft             From fiscal years 2011 through 2019, the B-2 fleet’s aircraft availability and
                                     mission capable rates increased. The fleet did not meet any of its annual
Depot maintenance activity           aircraft availability goals and met or exceeded its annual mission capability
and squadron locations:              goals in 3 of the 9 years during this time period. Total operating and support
                                     (O&S) costs remained stable over the past several years, averaging around
                                     $860 million per year, though costs were above this amount in fiscal years
                                     2012 and 2018. In fiscal year 2018 O&S costs totaled $885.49 million, with
                                     about 42 percent, or $373.77 million, spent on maintenance. Total O&S costs
                                     per aircraft increased slightly, from $42.97 million in fiscal year 2011 to
                                     $44.27 million in fiscal year 2018, and maintenance costs per aircraft also
                                     increased slightly during this same time period, from $17.76 million per
                                     aircraft to $18.69 million. The B-2 is currently undergoing several upgrades to
                                     various systems. The Air Force plans to use the aircraft until at least 2030.

                                     B-2 Sustainment Status




Sustainment Challenges
and Mitigation Actions
The B-2 faces sustainment
challenges related to supply of
needed parts and maintenance of
its low-observable coating. The
program office is working to
increase the availability of parts
and has implemented a program
to improve low-observable
maintenance.



Page 53                                                                       GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The Life Cycle Sustainment Plan for the B-2 (July 2019) describes the program’s sustainment strategy as
   focusing on parts obsolescence management, cybersecurity concerns, and maintaining the low-observable
   capacity of the aircraft, among other things. The plan also describes the structure and responsibilities for depot
   maintenance.

•   Sustainment of the B-2 fleet is accomplished through programmed depot maintenance, which is performed on a
    9-year cycle, with two aircraft entering programmed depot maintenance each fiscal year. The aircraft is also
    undergoing several modifications, including to its communications, navigation, and weapon systems and the
    program office is working to conduct these modifications concurrently with programmed depot maintenance.

•   Depot maintenance on the B-2 is conducted by Northrop Grumman. The supply chain for the B-2 is managed by
    the Air Force’s Supply Chain Management Wing.


 Availability and Condition
The B-2 fleet’s aircraft availability rate increased from fiscal years 2011 through 2019, but the aircraft did not meet
any of its annual aircraft availability goals during the time period. The B-2 fleet did not meet any of its availability
goals even though the Air Force’s Global Strike Command lowered the B-2’s aircraft availability goal in fiscal year
2018 to better align with operational plans, according to program officials. The B-2’s mission capable rate also
increased from fiscal year 2011 to fiscal year 2019, and the fleet met or exceeded its mission capable goals in 3 of
the 9 fiscal years during the time period.

The B-2 fleet’s not mission capable maintenance and not mission capable supply rates both decreased from fiscal
years 2011 through 2019 and contributed to the increase in the mission capable rate. Program office officials
attributed the increase in the B-2 fleet’s mission capable rate to efforts to improve maintenance of the low-
observable coating, the the responsiveness of the supply chain, and a reduction in the programmed depot
maintenance cycle time. Specific details on mission capable and not mission capable rates were omitted because
the information was deemed by DOD to be sensitive.


 Operating and Support Costs
Operating and support costs for the B-2 remained stable—around $860 million a year—from fiscal year 2011 until
they increased slightly in fiscal year 2018. Maintenance was the largest cost driver, accounting for about 42 percent
of the total cost in fiscal year 2018.




Page 54                                                                            GAO-21-101SP Weapon System Sustainment
B-2 Total Operating and Support Costs




Total O&S costs per aircraft and maintenance costs per aircraft for the B-2 slightly increased over the 7 year period.
Total O&S costs per aircraft rose from $42.97 million in fiscal year 2011 to $44.27 million in fiscal year 2018.
Maintenance costs per aircraft increased from $17.76 million per aircraft to $18.69 million during this time period.
The number of aircraft in the B-2 fleet remained at 20 since fiscal year 2011.




Page 55                                                                         GAO-21-101SP Weapon System Sustainment
B-2 Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Supply: Program office officials told us that they have had difficulty obtaining needed parts from the supply chain
because the B-2 is a low-density, high-demand fleet. According to program office officials, because of the low
number of aircraft in the B-2 fleet, there is less demand for suppliers to build parts, resulting in decreased parts
availability. This parts shortage routinely leads to cannibalization—that is, taking a part from one aircraft and using it
on another—of aircraft in depot. While this process fixes an immediate need, it is also inefficient. The B-2 program
office has been working with the Air Force’s Supply Chain Management Wing to address this issue. Supply chain
improvement efforts include redesigning obsolete hardware to ensure that aging parts are procurable and reparable
for the future.

Maintenance: A unique sustainment challenge of the B-2 is the maintenance of the low-observable coating. The
program implemented several projects aimed at maintaining the stealth capability of the B-2 by monitoring,
maintaining, and enhancing the signature of the aircraft. In addition to these specific sustainment efforts, the
program must assess the impact of any modifications to the low-observable coating early in the planning stages.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 56                                                                            GAO-21-101SP Weapon System Sustainment
                                         B-52 Stratofortress Sustainment Quick Look
                                         Common Name: B-52
                                         Lead Service: Air Force

                                         Background
Program Essentials                       The B-52 Stratofortress is a long-range, heavy bomber that can perform a
                                         variety of missions, including strategic attack, close air support, air
Manufacturer: Boeing
                                         interdiction, maritime operations, and offensive counter-air missions. It can
Sustainment: Depot maintenance           carry nuclear or precision-guided conventional ordnance with worldwide
conducted organically at the             precision navigation capability. The B-52 has been operating for over 65
designated air logistics complex         years and the Air Force plans to continue operating it into the 2050s, making
and contractually for some depot-        it one of the longest serving aircraft in the Air Force.
level repairs at contractor facilities
                                         Life Cycle of the B-52
Program Office: Tinker Air Force
Base, Oklahoma
Fiscal Year 2019 Data
Average age: 59 years
Average lifetime flying hours:
19,786 hours per aircraft
Depot maintenance activity               Overview
and squadron locations:                  From fiscal years 2011 through 2019, the B-52 fleet met or exceeded its
                                         annual aircraft availability goals in 2 of the 9 years, and met or exceeded its
                                         annual mission capable goals in 3 of the 9 years. Both rates decreased
                                         during the time period. Total operating and support costs remained relatively
                                         stable from fiscal years 2016 through 2018, hovering around $1.3 billion per
                                         year. For example, in fiscal year 2018 operating and support (O&S) costs
                                         totaled $1.37 billion, with 38 percent, or $513.02 million, spent on
                                         maintenance. Total operating and support costs per aircraft increased slightly
                                         since fiscal year 2011, from $16.91 million to $18.21 million. Maintenance
                                         cost per aircraft also slightly increased, from $5.85 million to $6.84 million.
                                         The percentage of costs spent on maintenance increased slightly, from 35
                                         percent in fiscal year 2011 to 38 percent in fiscal year 2018.

                                         B-52 Sustainment Status


Sustainment Challenges
and Mitigation Actions
The B-52 faces sustainment
challenges related to its age, and,
according to officials, parts are
difficult to obtain. Several
modification efforts are underway,
including a replacement of the
engine.




Page 57                                                                           GAO-21-101SP Weapon System Sustainment
Sustainment Strategy
• The Air Force accomplishes core sustainment of the fleet through programmed depot maintenance, which it
   performs on a 4-year cycle, with 17 aircraft entering the program depot maintenance each fiscal year. The B-52
   package includes inspections of critical structures and systems, with repairs conducted as needed along with
   known, incoming defects requiring repair or replacement. The B-52 originally had a planned service life of
   approximately 20 years. However, the Air Force now plans to sustain the B-52 until at least 2050.

•   The B-52H – Weapon System O&S Program Life-Cycle Sustainment Plan, issued in October 2018, describes the
    approach and resources necessary to develop and integrate sustainment requirements into the weapon system’s
    design, development, testing and evaluation, fielding, and operations. The life-cycle sustainment plan’s goal is to
    ensure that sustainment considerations are integrated into all planning, implementation, management, and
    oversight activities of the B-52 across its life cycle. The plan also refers to several recent and ongoing
    modification programs for the B-52, including upgrades to the weapons bay, modernization of the radar system,
    and replacement of the engine.


 Availability and Condition
The B-52 fleet met or exceeded its annual aircraft availability goals in 2 of the 9 years, and met or exceeded its
mission capable goals in 3 of the 9 years, from fiscal years 2011 through 2019. Additionally, the B-52 fleet was close
to meeting its aircraft availability goal in another fiscal year. Both the aircraft availability and mission capable rates
decreased during the time period. According to program officials, the decreasing aircraft availability and mission
capable rates were related to engine issues and modifications of the aircraft. Further, the aircraft is experiencing
structural issues due to its age. The program office is working closely with the Department of Defense and industry
experts to address these issues through scheduled maintenance and modifications.

The largest driver of the B-52’s mission capable rate from fiscal years 2011 through 2019 was maintenance. The not
mission capable maintenance rate increased during the time period, while the rate for not mission capable supply
was variable and almost the same in fiscal year 2019 and fiscal year 2011. According to program officials, the B-
52’s largest maintenance driver was the aircraft’s engine. Specific details on mission capable and not mission
capable rates were omitted because the information was deemed by DOD to be sensitive.


Operating and Support Costs
Total O&S costs for the B-52 remained relatively steady at around $1.3 billion from fiscal years 2016 through 2019.
Maintenance accounted for 38 percent, or $513.02 million, of the total cost in fiscal year 2018.




Page 58                                                                           GAO-21-101SP Weapon System Sustainment
B-52 Total Operating and Support Costs




Costs per aircraft increased slightly since fiscal year 2011. Specifically, in fiscal year 2011 O&S costs per aircraft
were $16.91 million, and in fiscal year 2018 they were $18.21 million. Maintenance costs were the largest
percentage of overall costs and fluctuated year to year during this time period, resulting in an increase from $5.85
million per aircraft in fiscal year 2011 to $6.84 million per aircraft in fiscal year 2018.




Page 59                                                                           GAO-21-101SP Weapon System Sustainment
B-52 Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging and Maintenance: The B-52 is experiencing stress and fatigue in its airframe and components, as the B-52
is one of the oldest systems operating in the Air Force. For example,

    •     B-52 program officials cited a 40 percent increase in landing gear structural cracks in recent years.
          Maintainers also identified cracks in the lower segment, a beam providing airframe structural support. Many
          of these stress and fatigue issues require an engineering solution because manufacturers and vendors are
          either no longer available or not cost-effective. When these issues are first identified, significant time is
          required to formulate the correct solution. Over time, the repairs become more routine and efficient. For
          example, maintainers said that the first repair of the landing gear structure took 90 days but is now taking
          about 30 days. Also, B-52 program officials plan to continue working with vendors and their engineering
          support to find solutions for issues such as the beam in the lower segment and to buy spare parts in
          advance.
    •     The B-52 communications suite was first designed in the 1940s. Officials said that the upgrade to the new
          system requires 7,000 work hours for installation per plane and is challenging to complete during
          programmed depot maintenance.
    •     The B-52 also has issues with stress and fatigue of its engine. In January 2017 an engine failed in flight. To
          keep the aircraft flying, Congress and the Air Force have agreed to allocate $1.466 billion in development
          spending for new engines for the B-52 aircraft, with initial operational capability scheduled for fiscal year
          2027.

Supply Support: Department of Defense supply-chain managers sometimes have difficulty finding sources of
supply for the B-52 because original manufacturers may not make the parts and obtaining repair parts can
sometimes take years. The program office is working on developing a Diminishing Manufacturing Sources and
Material Shortages Plan to address parts obsolescence issues.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.



Page 60                                                                            GAO-21-101SP Weapon System Sustainment
Page 61   GAO-21-101SP Weapon System Sustainment
                                    C-2A Greyhound Logistics Aircraft Sustainment
                                    Quick Look
                                    Common Name: C-2A
                                    Lead Service: Navy

Program Essentials                  Background
Manufacturer: Grumman               The C-2A Greyhound Logistics Aircraft is a twin-engine monoplane cargo
Corporation (acquired by Northrop   aircraft first manufactured in 1965. It is designed to land on aircraft carriers
Grumman)                            and provide logistics support to Carrier Strike Groups, such as transporting
Sustainment: Depot maintenance      high-priority cargo and passengers.
conducted at Navy Fleet
Readiness Centers; and field        Life Cycle of the C-2A
maintenance conducted by Navy
maintainers
Program Office: Program
Manager – Air 231, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data               Overview
Average age: 32.2 years
                                    From fiscal years 2011 through 2019, the C-2A fleet did not meet any of its
Average lifetime flying hours:      annual mission capability goals and its mission capable rate decreased. The
10,677 hours per aircraft           C-2A’s mission capable rate decreased because of unexpected and
                                    extensive repairs on landing gears and outer wing panels, according to
Depot maintenance activity          program officials. Total operating and support (O&S) costs generally
and squadron locations:             decreased from about $239.77 million in fiscal year 2011 to about $218.29
                                    million in fiscal year 2018. Specifically, unit-level manpower, unit operations,
                                    and continuing system improvements costs decreased, while maintenance
                                    costs fluctuated during the period. In fiscal year 2018, maintenance costs per
                                    aircraft accounted for almost half of the total costs per aircraft because,
                                    according to officials, of an increase in overall repairs to the aging aircraft.

                                    C-2A Sustainment Status




Sustainment Challenges
and Mitigation Actions
The C-2A is operating beyond its
planned service life with
maintenance and supply
challenges. Actions to mitigate
these challenges include moving
aircraft to deploying squadrons,
and locating other vendors for
parts.


Page 62                                                                        GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• Sustainment planning for the C-2A is focused on providing support for major components, such as the engine,
   landing gear, and avionics system, among others. According to officials, since the C-2A has a similar airframe to
   the E-2D Advanced Hawkeye Early Warning and Control Aircraft, they will include an appendix for the C-2A
   when they update the sustainment strategy for the E-2D for its 5-year update in fiscal year 2020.

•   The original C-2A aircraft were overhauled to extend their operational life in 1973 and again from 2004 through
    2011. The Navy completed the service life extension program from 2004 through 2011 to increase flight hours
    from 10,000 to 15,000 and landings from 16,020 to 36,000, among other things.

•   The Navy Fleet Readiness Centers maintain the aircraft using planned maintenance intervals, which typically
    occurs every 24 months. Also, the Naval Supply Systems Command and Defense Logistics Agency provide
    supply support for the aircraft.


 Availability and Condition
From fiscal year 2011 through fiscal year 2019, the C-2A fleet missed all of its annual mission capable goals and its
mission capable rate decreased. According to officials, the Navy did not focus on mission capable rates as a key
metric in the past. While the Navy has renewed its focus on improving C-2A mission capability and made some
improvements in the C-2A mission capable rate, program officials said that meeting the goal continues to be a
challenge. However, they told us that they believe the program will be able to meet the goal beginning in 2021.

From fiscal year 2011 through fiscal year 2019, the rates increased for not mission capable maintenance and not
mission capable supply (NMCS). According to officials, the NMCS rate increased because the supply system was
not prepared for the immediate increase in demand for parts that resulted from the efforts to reach the mission
capable goal. Officials told us that the not mission capable rates can also fluctuate due to unexpected repairs, such
as extensive repairs on landing gears and outer wing panels. Specific details on mission capable and not mission
capable rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the C-2A’s total O&S costs fluctuated. Maintenance costs accounted
for the largest share of O&S costs over the period, averaging about $95.53 million per year, or 44 percent of total
O&S cost, but also fluctuated. According to officials, sustainment costs for the aging C-2A have increased, in part,
due to limited sourcing options for parts and the substantial number of obsolescence challenges. Navy officials said
they have to work harder to locate new parts once a part is no longer being manufactured, and in some cases
require the depot to manufacture parts that would have been purchased, which increases the depot maintenance
costs. As such, depot-level reparables was the most significant category of maintenance costs, averaging about
$36.31 million per year, or 38 percent of the C-2A’s total maintenance costs from fiscal years 2011 through 2018.
The other maintenance cost category was the smallest share, averaging about $6.09 million per year, or 6 percent
of the total maintenance costs during the same time period.




Page 63                                                                         GAO-21-101SP Weapon System Sustainment
C-2A Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the C-2A’s O&S costs per aircraft remained steady, averaging about
$6.47 million per year. Also, maintenance costs per aircraft, on average, accounted for more than one-third of the
total O&S costs per aircraft, averaging about $2.84 million per year during the same time period. According to
officials, this was a result of the increase in overall repairs to the aging aircraft and included costly repairs to the
flight control surfaces and landing gear, among other maintenance. The number of aircraft remained relatively
steady from 34 aircraft in fiscal year 2011 to 33 aircraft in fiscal year 2018.




Page 64                                                                          GAO-21-101SP Weapon System Sustainment
C-2A Operating and Support Costs per Aircraft




Sustainment Challenges and Mitigation Actions
Aging: The C-2A has been in operation for close to 50 years, with current aircraft about 29 to 34 years old. The
Navy completed a service life extension program for the C-2A from 2004 through 2011 to increase the aircraft’s
flight hours and landings, among other things. In response to low aircraft inventory, the Navy’s ongoing approach to
mitigate these challenges includes moving aircraft between squadrons to meet the requirements of deploying
missions.

Maintenance: As the C-2A ages, it requires additional maintenance for repairs that were not originally planned,
such as repairs for the propeller system and outer wing panels, which are nearing their 7,500 flight hour limit. Also,
maintenance for these aircraft is taking longer because more parts need to be repaired and replaced. Additionally,
according to Navy officials, there is a shortage of depot and field maintenance personnel due to attrition, inability to
find skilled workers, and hiring freezes. The Navy’s ongoing and planned actions include: conducting system
performance studies to identify maintenance tasks to mitigate potential failures, identifying all parts and components
that need to be repaired and replaced during the inspection phase, training depot and field maintainers and other
personnel to transition to vacated positions and to be proficient in repairing all parts of the aircraft, and allowing
depot and field maintainers to work overtime to keep up with maintenance schedules.

Supply Support: The C-2A is experiencing increased shortages of parts because vendors are no longer producing
some of the aircraft’s parts. According to Navy officials, there is not enough demand for manufacturers to keep
production lines open or to propose redesigns of parts. The Navy’s ongoing and planned actions include locating
other vendor sources, upgrading hardware and software, reverse engineering (the process of examining an item,
such as a spare part, with the intent of replicating its design), and as a last resort, cannibalizing parts (i.e., removing
serviceable parts from one aircraft and installing them in another aircraft).


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 65                                                                             GAO-21-101SP Weapon System Sustainment
                                    C-130T Hercules Sustainment Quick Look
                                    Common Name: C-130T
                                    Lead Services: Navy and Marine Corps

                                    Background
Program Essentials                  The C-130T Hercules was first manufactured in 1990 and last produced in
Manufacturer: Lockheed Martin       1996. The C-130T is a multi-role, long-range land-based tactical aircraft that
                                    provides intra-theater logistics support for deployed Navy forces, air-to-air
Sustainment: Depot maintenance      refueling to fleet operating forces, search and rescue, flight demonstration,
conducted at Air Logistic Complex   and transport of personnel and cargo.
at Ogden, Utah, and field
maintenance conducted by Navy       Life Cycle of the C-130T
maintainers
Program Office: Program
Manager – Air 207, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 25.39 years
                                    Overview
Average lifetime flying hours:      From fiscal years 2011 through 2019, the C-130T fleet did not meet any of its
18,624 hours                        annual mission capable goals and its mission capable rate decreased during
Depot maintenance activity          this time period. The C-130T’s mission capable rate decreased largely due to
and squadron locations:             a fatal accident in fiscal year 2017 caused by a propeller malfunction on the
                                    aircraft. Total operating and support (O&S) costs fluctuated, averaging about
                                    $166.48 million per year from fiscal years 2011 through 2018. Specifically,
                                    unit-level manpower and unit operations costs decreased over this time
                                    period while costs related to maintenance and continuing system
                                    improvements increased. According to Navy officials, the cost increases were
                                    associated with efforts to modernize the aircraft as well as modifications to
                                    replace the propellers on the aircraft. Further, in fiscal year 2018,
                                    maintenance costs per aircraft accounted for more than one-third of the total
                                    O&S costs per aircraft.

                                    C-130T Sustainment Status




Sustainment Challenges
and Mitigation Actions
The C-130T is an aging aircraft
with maintenance and supply
challenges. Planned actions to
mitigate these challenges include
modernization initiatives to
upgrade the aircraft and an
obsolescence program to procure
hardware and software
components.


Page 66                                                                      GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The C-130T is a variant of the Air Force’s commercially developed C-130 Hercules transport aircraft. As a
   variant, it shares similar hardware and software configurations, costs for development of common capabilities,
   and a common product support infrastructure. Depot maintenance for the C-130T is conducted at Air Logistic
   Complex at Ogden, Utah. Navy and Marine Corps personnel conduct field maintenance on the C-130T.

•   In a statement to Congress, the Navy stated that the C-130T modernization initiatives include upgrading the
    propeller system by replacing the legacy four-blade system with an eight-blade high thrust composite blade
    system, among other initiatives. The Navy anticipates that all aircraft will be fully modified by fiscal year 2020.
    The Navy is also modernizing the C-130T brake system with carbon brakes designed to provide enhanced
    safety and maintainability at a reduced weight over the current steel brake assemblies. The Navy’s initiatives will
    reduce maintenance, sustainment, and fuel costs. The Navy plans to complete installing the modernized brake
    system by the end of fiscal year 2020.

•   In 2018, the Navy implemented an Avionics Obsolescence Upgrade Program for the C-130T to mitigate
    obsolescence issues (i.e., when a part is not available due to its lack of usefulness or it is no longer current or
    available for production) by procuring avionics software with associated commercial off-the-shelf hardware and
    integrating avionics software and associated components into the aircraft. The Navy’s Avionics Obsolescence
    Upgrade Program also incorporates multiple aircraft improvements to increase aircrew and passenger safety,
    such as improved aircraft avoidance and awareness system and a digital flight data recorder.


 Availability and Condition
From fiscal year 2011 through fiscal year 2019, the C-130T missed all of its annual mission capable goals, though it
was close to meeting its goal one fiscal year, and its mission capable rate decreased during the time period.
According to officials, one reason for the mission capable rate decrease was that the Navy grounded the fleet in
fiscal year 2017 after a fatal accident caused by a propeller malfunction on the aircraft. To expedite the fleet
returning to flight, the U.S. Air Force, which is the source of supply for propellers for the family of C-130 aircraft,
prioritized propellers needed for Navy and Marine Corps aircraft. This assisted in increasing the mission capable
rate, though it was still below the fiscal year 2011 level in fiscal year 2019.

From fiscal year 2011 through fiscal year 2019, the rates increased for not mission capable maintenance and not
mission capable supply. According to officials, the aircraft that were awaiting delivery of new propellers––after the
fiscal year 2017 fatal accident caused by a propeller malfunction on the aircraft––were a contributing factor to these
rates during this time period. Specific details on mission capable and not mission capable rates were omitted
because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the C-130T’s O&S costs fluctuated averaging about $166.48 million
per year. According to officials, O&S costs increased in fiscal years 2017 and 2018 as a result of the modernization
and replacement of the aircraft’s propellers. Maintenance costs increased during this period and also accounted for
the largest share of the C-130T’s O&S costs, averaging about $56.85 million per year, or 34 percent of the total
O&S costs from fiscal years 2011 through 2018. According to officials, this was a result of costs associated with
aviation depot level reparables and depot events for the aircraft. As such, depot maintenance was the most
significant category of maintenance costs, averaging about $19.64 million per year from fiscal years 2011 through
2018, or 35 percent of the total maintenance costs during that time period. Intermediate maintenance and
consumable materials and repair parts accounted for the smallest shares of the C-130T’s maintenance costs, with
each category averaging about $10.56 million and $10.59 million per year, respectively, or about 19 percent of the
total maintenance costs from fiscal years 2011 through 2018.




Page 67                                                                           GAO-21-101SP Weapon System Sustainment
C-130T Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the C-130T’s O&S costs per aircraft remained generally steady,
averaging about $8.53 million per year. According to officials, the increase in fiscal year 2012 can be attributed to
maintenance activities to modernize components on the aircraft. Also, maintenance costs per aircraft, on average,
accounted for more than one-third of the total O&S costs per aircraft, averaging about $2.92 million per year.
Additionally, the number of aircraft remained relatively steady from 20 aircraft in fiscal year 2011 to 19 aircraft in
fiscal year 2018.




Page 68                                                                          GAO-21-101SP Weapon System Sustainment
C-130T Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: The C-130T has been operating for close to 30 years and, according to program officials, has undergone a
series of modifications to replace or enhance aging components. Navy and Marine Corps officials told us that they
have updated operating techniques to meet mission and training requirements during this time, which has also
driven modifications to the aircraft. In its testimony to Congress, the Navy stated several planned modernization
initiatives to update systems and parts to extend the life of the aircraft, such as the propeller modifications.

Maintenance: As the C-130T ages, according to officials, it has required additional maintenance for repairs that
were not originally planned, such as repairs to the propeller system. Also, maintenance for the aircraft is taking
longer because more parts need to be repaired and replaced. The Navy and Marine Corps’ ongoing and planned
actions to mitigate these challenges, according to officials, include maintenance initiatives, such as scheduling
maintenance for components based on forecasted failure rates for those components, and updating technical
publications and training tasks to ensure that training is consistent with the maintenance tasks necessary to support
the aircraft. Additionally, the Navy and Marine Corps are pursuing an automated system that will store interactive
electronic technical manuals allowing for quicker updates, and providing maintainers with step-by-step instructions
on repairing components on the aircraft.

Supply Support: The C-130T is experiencing some shortages of parts because, according to officials, the size of
the fleet causes very low and unanticipated demand resulting in items not being ordered and available in stock;
which can affect mission capable rates. The Navy and Marine Corps’ planned actions to mitigate these challenges
include initiatives, such as the Avionics Obsolescence Upgrade Program, to procure avionics software with
associated, commercially-available hardware through existing government contracts and integrating avionics
software and associated components into the aircraft to update these systems and components. Also, according to
officials, the Navy and Marine Corps are pursuing an automated system that will capture data from the aircraft and
aircrew to allow maintainers to proactively order parts and materials.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.



Page 69                                                                         GAO-21-101SP Weapon System Sustainment
                                     C-5M Super Galaxy Sustainment Quick Look
                                     Common Name: C-5M
                                     Lead Service: Air Force

                                     Background
Program Essentials                   The C-5 was first manufactured in 1970. The C-5M Super Galaxy is a
                                     strategic transport aircraft and is the largest aircraft in the Air Force inventory.
Manufacturer: Lockheed Martin-
                                     Its primary mission is to transport cargo and personnel for the Department of
Georgia Company
                                     Defense. By the end of fiscal year 2018, all remaining legacy C-5 models
Sustainment: Depot maintenance       were modified and redesignated as the C-5M.
conducted by the Air Force at
Warner Robins Air Logistics          Life Cycle of the C-5
Complex, Georgia, and field-level
maintenance performed by Air
Force maintainers
Program Office: Robins Air Force
Base, Georgia
Fiscal Year 2019 Data
Average age: 32 years
                                     Overview
Average lifetime flying hours:
21,900 hours per aircraft            From fiscal years 2011 through 2019, the C-5 did not meet any of its annual
                                     aircraft availability goals, but met or exceeded its mission capable goals in 2
Depot maintenance activity           of these 9 fiscal years. The aircraft availability and mission capable rates
and squadron locations:              both increased during the time period. Total operating and support (O&S)
                                     costs for the C-5 fleet decreased from about $3.38 billion in fiscal year 2011
                                     to about $1.05 billion in fiscal year 2018, in part because the Air Force retired
                                     59 C-5 aircraft, flew fewer flight hours, and made changes to the fleet
                                     structure during this time period. Costs for continuing system improvements
                                     decreased the most—from about $998 million to nearly $24 million—during
                                     the 8-year period. In fiscal year 2018, maintenance was the largest O&S cost
                                     category at almost $383 million. The C-5’s O&S costs per aircraft declined
                                     from $32.52 million to $21.34 million from fiscal year 2011 to fiscal year 2018.

                                     C-5M Sustainment Status




Sustainment Challenges
and Mitigation Actions
The C-5M faces issues with
corrosion stress cracks and
unscheduled maintenance. Repair
programs and the implementation
of a condition-based maintenance
are examples of mitigation actions
being taken to address these
challenges.




Page 70                                                                         GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The C-5M Super Galaxy Life Cycle Sustainment Plan was issued in April 2019 to document the sustainment
   strategy and guide sustainment activities.

•   Sustainment of the C-5M fleet is accomplished through a maintenance schedule including home station checks,
    major and minor inspections, and programmed depot maintenance. Programmed depot maintenance is
    performed on an 8-year cycle. From 2008 through 2018, the entire fleet underwent a modification program to
    upgrade the aircraft’s engines and other components.

•   C-5M depot maintenance is conducted at Warner Robins Air Logistics Complex, Georgia. The supply chain for
    the C-5 is primarily managed by the Air Force’s 448th Supply Chain Management Wing and the Defense
    Logistics Agency, but Lockheed Martin provides supply support for certain avionics items. Field level
    maintenance is conducted by Air Force active duty and reserve maintainers.


 Availability and Condition
From fiscal years 2011 through 2019, the aircraft availability rate for the C-5 fleet fell short of the goal each year, the
mission capable rate exceeded the goals in 2 of the 9 fiscal years, and both of the rates increased slightly.
According to officials, many of the factors that influenced the mission capable rate also drove the C-5’s aircraft
availability trend. In addition, they said that the retirement of low performing C-5A aircraft from fiscal years 2011
through 2017 improved the availability rate during some of those years.

From fiscal year 2011 through 2019, the not mission capable maintenance rate decreased, but the decrease was
partially offset by increases in the not mission capable supply rate and the not mission capable both rate. According
to Air Force officials, these trends occurred for several reasons, such as reliability improvements from a modification
program; landing gear component failures that grounded the fleet during a part of fiscal years 2017 and 2018; and
supply delays due to the unexpected demand for—and lengthy process to obtain—several unpriced components
provided by a supply-support contractor. Specific details on mission capable and not mission capable rates were
omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal years 2011 through 2018, the C-5’s overall O&S costs decreased by about $2.33 billion—from $3.38
billion to $1.05 billion. Continuing system improvements decreased the most, from about $998 million in fiscal year
2011 to about $24 million in fiscal year 2018. Maintenance costs also declined significantly, about $600.2 million,
during this timeframe. When comparing fiscal year 2011 to fiscal year 2018, unit operations and unit-level manpower
decreased by $378 million and $323 million, respectively. Air Force officials told us that there were several changes
to the C-5 fleet during this time period. More specifically, the Air Force retired 59 C-5A aircraft; consolidated the C-5
basing structure from eight main operating bases to four bases with two operating commands, the Air Mobility
Command and the Air Force Reserve Command; and converted all Air National Guard C-5 units to C-17 aircraft. As
a result, the smaller C-5 fleet flew fewer flight hours and required fewer maintenance actions, which reduced
associated supply costs. Finally, the costs for continuing system improvements decreased significantly from fiscal
years 2011 to 2018 as less money was spent on modifications to the aircraft to improve safety, reliability, or
maintainability, or to otherwise enable the system to meet its basic original operational requirements throughout its
life.




Page 71                                                                            GAO-21-101SP Weapon System Sustainment
C-5 Total Operating and Support Costs




Note: The figure includes data for C-5A, C-5B, C-5C, and C-5M aircraft.

As a result of the fleet changes noted above and a reduction in the amount of funding for certain modification
programs, among other reasons, the total O&S costs per aircraft decreased from $32.52 million in fiscal year 2011
to $21.34 million in fiscal year 2018. Maintenance costs per aircraft also decreased from $9.45 million to $7.81
million during this timeframe. Officials also told us that the C-5 program changed the maintenance concept in 2009
to reduce unscheduled maintenance and extend the maintenance intervals, and that a number of reliability
improvements were made to the program as part of ongoing modification programs.




Page 72                                                                       GAO-21-101SP Weapon System Sustainment
C-5 Operating and Support Costs per Aircraft and Fleet Size Capable Rates




Note: The figure includes data for all C-5A, C-5B, C-5C, and C-5M aircraft.


Sustainment Challenges and Mitigation Actions
Aging: According to Air Force officials, the C-5 fleet is experiencing stress corrosion cracking. Several major repair
programs have been initiated or are planned to mitigate this challenge. For example, officials said that the C-5M
Dorsal Complex Repair and Dagger Fitting Replacement program began in fiscal year 2016 to repair a crack on the
tail assembly of the aircraft and is expected to be completed in fiscal year 2020. The Pylon Wing Interface program
will repair cracks on the pylon to wing interface (the point where the engine attaches). This repair program is
planned to begin in fiscal year 2022. Finally, the Air Force officials told us that the Crown Skin Replacement
program, which is planned to begin in fiscal year 2024, will replace fuselage skins on two aircraft because the legacy
skins are prone to stress corrosion cracking.

Maintenance: Air Force officials told us that the amount of unscheduled maintenance is still a challenge for the C-5
fleet, despite having implemented a commercial maintenance concept to reduce unscheduled maintenance.
Therefore, officials said the C-5 program is in the process of implementing another new maintenance concept—
condition-based maintenance plus--that converts unscheduled maintenance to scheduled maintenance by
identifying components and parts with high failure rates and prescribing the appropriate replacement intervals.
Implementation began early in fiscal year 2019. Eight components have been identified and are currently
undergoing studies to improve reliability, according to Air Force officials.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 73                                                                         GAO-21-101SP Weapon System Sustainment
                                    C-17 Globemaster III Sustainment Quick Look
                                    Common Name: C-17
                                    Lead Service: Air Force

                                    Background
Program Essentials                  The C-17 Globemaster III is a high-wing, four-engine cargo aircraft with a
Manufacturer: Boeing                rear loading ramp that was first manufactured in 1987. The C-17 has air-
                                    refueling capability and is capable of rapid strategic delivery of troops and all
Sustainment: Boeing is              types of cargo to main operating bases and bases in forward deployment
responsible for sustainment         areas. The C-17 can perform tactical airlift and airdrop missions and can
activities, such as material        transport ambulatory patients during aeromedical evacuations, when
management and depot                required.
maintenance support.
                                    Life Cycle of the C-17
Program Office: Robins Air Force
Base, Georgia, and Wright-
Patterson Air Force Base, Ohio
Fiscal Year 2019 Data
Average age: 16 years
Average lifetime flying hours:
15,293 hours per aircraft
                                    Overview
Depot maintenance activity
                                    The C-17 did not meet its annual aircraft availability and mission capable rate
and squadron locations:
                                    goals from fiscal years 2011 through 2019, and both rates decreased slightly
                                    during this time period. Total operating and support (O&S) costs for the C-17
                                    fleet decreased from $5.63 billion in fiscal year 2011 to $3.56 billion in fiscal
                                    year 2018 primarily due to reduced flying hours, fuel consumption, and fuel
                                    prices over this time period, according to program officials. In fiscal year
                                    2018, maintenance was the largest cost category and nearly all of these
                                    costs, about $1.28 billion, were contractor support costs. The annual O&S
                                    costs per aircraft declined from $27.05 million to $16.04 million as a result of
                                    decreased costs and increased aircraft inventory during this period.

                                    C-17 Sustainment Status




Sustainment Challenges
and Mitigation Actions
The C-17 faces challenges with
aging and maintenance. Mitigation
actions include upgrades and
capability improvements and
increasing the amount of time
between scheduled depot
maintenance and field-level
maintenance inspections.




Page 74                                                                       GAO-21-101SP Weapon System Sustainment
•Sustainment Strategy
• The C-17 Enterprise Life-Cycle Management Plan and Life-Cycle Sustainment Plan (2014) documents current
   and future acquisition, sustainment, and integration efforts. It also addresses contractual arrangements and
   partnership support agreements between Air Force, Boeing, and other sustainment providers.

• Boeing provides life-cycle support for the C-17 under the terms of the Globemaster Integrated Sustainment
  Program (2013). Under this program, Boeing is responsible for sustainment activities, such as material
  management and depot-maintenance support.

• Boeing provides oversight of C-17 depot maintenance that is conducted under a public-private partnership at
  Warner Robins Air Logistics Complex and at its facility in San Antonio. Landing gear overhauls occur at Ogden
  Air Logistics Complex and contractor facilities. Pratt & Whitney oversees engine overhauls at the Oklahoma City
  Air Logistics Complex under a public-private partnership, at the Pratt & Whitney Repair Center in Columbus,
  Georgia, and at the United Airlines Facility in San Francisco, California.


Availability and Condition
The C-17 fleet did not meet its annual aircraft availability or mission capable goals in fiscal years 2011 through
2019, but the rates were within one percentage point of both goals in two of the fiscal years earlier in the time
period, and both of the rates decreased slightly. According to program officials, the number of aircraft undergoing
scheduled and unscheduled depot-level maintenance were the primary drivers of the aircraft availability rate that
was below the goals. In addition, the officials said that the C-17’s aircraft availability and mission capable rates were
lower in fiscal year 2019 than in fiscal year 2011 due to an increase in the amount of time needed to complete a
scheduled, field-level maintenance inspection; a depot-level upgrade to the latest airplane tracking system used by
the Federal Aviation Administration’s air traffic control; and supply challenges.

From fiscal year 2011 through 2019, the rates increased slightly for not mission capable maintenance, not mission
capable supply, and not mission capable both supply and maintenance. Program officials told us that the amount of
time needed to complete regularly-scheduled, field-level maintenance inspections was the largest driver of not
mission capable time. Officials explained that, during these years, the C-17 fleet was transitioning aircraft from
active Air Force bases to Air National Guard and Air Force Reserve bases. These inspections take an average of 12
days longer to complete at the Guard and Reserve bases because there is typically only one funded maintenance
shift, compared to three shifts at active bases. Specific details on mission capable and not mission capable rates
were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the C-17’s total O&S costs decreased by about $2.06 billion, from
$5.63 billion to $3.56 billion. Unit operations costs decreased the most, about $1.43 billion, during this timeframe.
According to program officials, unit operations costs decreased because the C-17 fleet executed fewer flying hours
and thus used less fuel in fiscal year 2018 than in fiscal year 2011. Further, fuel costs also decreased over this time
period. Maintenance costs varied from fiscal years 2011 through 2017, but were above the fiscal year 2011 total of
$1.58 billion. However, in fiscal year 2018, maintenance costs dropped to about $1.28 billion, about $300 million
below the fiscal year 2011 total. Officials stated that maintenance costs were less in fiscal year 2018 because of
reduced contractor support costs for engine depot maintenance as the Air Force began to transition this work to its
own maintenance depot. In fiscal year 2018, maintenance was the largest cost category and nearly all of the $1.28
billion were contractor support costs.




Page 75                                                                           GAO-21-101SP Weapon System Sustainment
C-17 Total Operating and Support Costs




From fiscal years 2011 through 2018, the O&S costs per C-17 aircraft declined from $27.05 million to $16.04 million
as a result of decreased O&S costs and an increase in the aircraft inventory during this period. The C-17 inventory
increased by 14 aircraft, from 208 to 222, between fiscal years 2011 and 2014 and has remained at 222 aircraft
since fiscal year 2014.




Page 76                                                                       GAO-21-101SP Weapon System Sustainment
C-17 Operating and Support Costs per Aircraft and Fleet Size Capable Rate




 Sustainment Challenges and Mitigation Actions
Aging: The C-17 will continue to be modified to meet its requirements. The Air Force’s ongoing and planned
actions, according to program officials, include establishing specific teams, such as the weapon system integrity
program, that are responsible for creating a plan to better sustain the C-17 and increase its service life.

Maintenance: Program officials said the C-17 requires depot modifications to keep it viable, such as upgrading the
communications system and other capability modifications, which reduces the amount of time the aircraft is
available for training and mission requirements. Officials also said that the Air Force has found increased amounts
of corrosion on the aircraft, which requires intensive sheet metal work to repair. To minimize aircraft downtime, the
Air Force makes corrosion repairs while the aircraft is undergoing other heavy maintenance or repairs at a
designated base. Finally, officials told us that, as part of its Aircraft Availability Improvement Program, the program
increased the intervals between the scheduled field-level maintenance inspections from 120 days to 180 days at the
beginning of 2018. Additionally, starting in fiscal year 2020, the program plans to extend the amount of time between
scheduled depot maintenance inductions from 5 years to 6 years.

Supply Support: Program officials said some vendors were no longer manufacturing parts and expressed concern
that this could lead to future parts shortages. The Air Force’s ongoing and planned actions, according to program
officials, include upgrading aircraft systems before they become obsolete, locating other vendor sources,
redesigning parts, and purchasing additional parts to maintain supply sources.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 77                                                                         GAO-21-101SP Weapon System Sustainment
                                    C-130H Hercules Sustainment Quick Look
                                    Common Name: C-130H
                                    Lead Service: Air Force

                                    Background
Program Essentials                  The C-130H Hercules was first manufactured in 1965 and the first deliveries
                                    to the Air Force began in 1974. Basic and specialized versions of the four-
Manufacturer: Lockheed Martin
                                    engine turboprop aircraft perform a variety of missions including airlift
Sustainment: Depot maintenance      support, aeromedical, weather reconnaissance, and natural disaster relief.
conducted at Warner Robins Air
Logistics Complex, Georgia          Life Cycle of the C-130H

Program Office: Robins Air Force
Base, Georgia, and Wright-
Patterson Air Force Base, Dayton,
Ohio
Fiscal Year 2019 Data
Average age: 29.4 years             Note: According to program officials, it is unknown when the C-130H reached initial and full operating
                                    capability and there is not a projected sunset date for this aircraft.
Average lifetime flying hours:
12,744 hours per aircraft
                                    Overview
Depot maintenance activity          From fiscal years 2011 through 2019, the C-130 fleet met its annual aircraft
and squadron locations:             availability and mission capability goals in 1 of the 9 fiscal years, and 2 of the
                                    9 fiscal years, respectively, and both rates decreased during the time period.
                                    From fiscal year 2011 through 2018, the size of the C-130H fleet decreased
                                    from 268 to 179 due to the retirement of C-130H aircraft and one crash loss.
                                    Also, according to Air Force officials, all C-130H aircraft in the active force
                                    were moved to Air Force Reserve and Air National Guard units by fiscal year
                                    2015. Operating and support (O&S) costs decreased from about $2.70 billion
                                    to $1.38 billion from fiscal years 2011 through 2018 and most of the cost
                                    decrease occurred in the unit level manpower, unit operations, and
                                    maintenance cost categories. The total O&S costs per aircraft went down
                                    from $10.08 million in fiscal year 2011 to $7.69 million in fiscal year 2018.

                                    C-130H Sustainment Status




Sustainment Challenges
and Mitigation Actions
The C-130H faces sustainment
challenges such as increasing
maintenance requirements and
parts obsolescence. Mitigation
actions include initiatives to
reduce unscheduled maintenance
and scheduled maintenance and a
program to address diminishing
manufacturing sources and
material shortages.



Page 78                                                                                  GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The Air Force issued the C-130H Hercules Life-Cycle Management Plan in January 2012 to provide guidance
   for sustaining and maintaining the C-130H fleet. Air Force officials said they expect to complete the development
   of a single, updated life-cycle support plan for both the C-130H and C-130J aircraft in fiscal year 2020.

•   The Air Force sustains the C-130H fleet through modifications and programmed depot maintenance, which is
    performed on a 69-month cycle with about 30 aircraft inducted each year.

•   Depot maintenance is conducted by the Air Force at Warner Robins Air Logistics Complex, Georgia, and field
    maintenance is performed by Air Force Reserve Command and Air Force National Guard personnel. According
    to Air Force officials, spare parts, engines and propellers are all managed and maintained by the Defense
    Logistics Agency and the Air Force Sustainment Center.


 Availability and Condition
From fiscal year 2011 through fiscal year 2019, the C-130H fleet met its aircraft availability goal in 1 of the 9 fiscal
years and its mission capable goals in 2 of the 9 fiscal years, and was close to meeting those goals in several other
years. Over the period the aircraft availability rate and mission capable rate varied, but generally decreased. Air
Force officials said that extended downtime prior to aircraft retirements and for programmed depot maintenance and
increased system modifications negatively affected the C-130H fleet’s availability rates.

From fiscal year 2011 through 2019, the C-130H’s not mission capable maintenance (NMCM) rate varied, and the
not mission capable both (NMCB) maintenance and supply rate steadily increased. The not mission capable supply
rate varied slightly during the time period. According to officials, increased scheduled maintenance rates, increased
parts supportability issues, and force structure changes caused the higher not mission capable rates. With regard to
force structure changes and scheduled maintenance rates, officials said that the 61 remaining active duty C-130H
aircraft were transferred to Air Force Reserve Command and Air National Guard units during this time period. As a
result, the downtime for subsequent field-level maintenance on these aircraft increased because the receiving units
were manned only for one maintenance shift per day, while the active duty had three shifts. Additionally, officials
said the C-130H unit structure within the Air Force Reserve Command and the Air National Guard changed. Units
that did not previously have C-130H aircraft needed time to train and equip their maintainers, which led to higher
maintenance rates in certain years. Officials said that the NMCB rate rose higher due to supply issues, such as
problems the program faced replacing failed landing gear components. Specific details on mission capable and not
mission capable rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through 2018, the total O&S costs for the C-130H fleet decreased approximately $1.32 billion,
from about $2.70 billion to $1.38 billion. About 78 percent of the O&S cost decrease, or about $1.03 billion, occurred
in three cost categories. More specifically, unit level manpower decreased by about $362.68 million, unit operations
decreased by about $333.27 million, and maintenance costs decreased by about $334.98 million. According to Air
Force officials, C-130H’s O&S costs decreased largely because the Air Force retired aircraft during the 8-year
period. The C-130H fleet size was reduced from 268 aircraft in fiscal year 2011 to 179 aircraft in fiscal year 2018.
Officials said that unit operations costs decreased not only as a result of reduced flight hours—the fleet flew almost
50 percent fewer hours in fiscal year 2018 than in fiscal year 2011—but because fuel prices were lower in fiscal year
2018. With respect to unit level manpower, officials told us that costs decreased because there were a smaller
number of C-130H personnel and because the program had less military and more civilians, which are less
expensive, when comparing fiscal year 2011 to fiscal year 2018.




Page 79                                                                          GAO-21-101SP Weapon System Sustainment
C-130H Total Operating and Support Costs




The C-130H’s total O&S costs per aircraft decreased from $10.08 million in fiscal year 2011 to $7.69 million in fiscal
year 2018.The maintenance costs per aircraft decreased slightly from $3.06 million in 2011 to $2.71 million in 2018.
As noted earlier, the C-130H fleet decreased by 89 aircraft and total O&S costs decreased by $1.32 billion during
this 8-year period, reducing the overall cost per aircraft.




Page 80                                                                         GAO-21-101SP Weapon System Sustainment
C-130H Maintenance and Other Operating and Support Costs per Aircraft and Fleet Size




 Sustainment Challenges and Mitigation Actions
Maintenance: According to Air Force officials, the C-130H fleet is experiencing sustainment challenges that are
common to all aging aircraft fleets, such as corrosion, structural fatigue, and parts obsolescence. These issues led
to an increase in both field-level and depot-level maintenance, which are being addressed through a series of
maintenance and engineering initiatives. Within the maintenance communities, officials explained that technicians,
led by the Air Mobility Command, continually evaluate the methods for management of maintenance to reduce the
overall downtime. Within the engineering community, continuous analysis is performed to evaluate the effect of flight
operations and maintenance activities on the fleet, according to officials. The officials said they are currently
implementing condition based maintenance initiatives to provide a predictive parts failure replacement program
intended to reduce unscheduled maintenance by converting unscheduled maintenance to scheduled maintenance.
They said they are also working on programmed depot maintenance process improvements and regionalizing
scheduled maintenance inspections to reduce depot maintenance flow days and aircraft downtime.

Supply Support: Air Force officials said that the sustainment challenges faced by the aging C-130H fleet also
resulted in an increase in parts support requirements and a corresponding increase in diminishing manufacturing
sources and material shortages. According to officials, the C-130 program office has an active diminishing
manufacturing sources and material shortages program that started in 2015 to address both production and
sustainment supply-support issues. C-130 personnel at both Robins Air Force Base and Wright-Patterson Air Force
Base participate in broader Air Force Material Command parts efforts to identify and resolve these issues for the
C-130H fleet.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 81                                                                        GAO-21-101SP Weapon System Sustainment
                                    C-130J Super Hercules Sustainment Quick Look
                                    Common Name: C-130J
                                    Lead Service: Air Force

                                    Background
Program Essentials                  The C-130J Super Hercules was first manufactured in 1998 and deliveries to
Manufacturer: Lockheed Martin       the Air Force began in 1999. Basic and specialized versions of the four-
                                    engine turboprop aircraft perform a variety of missions including airlift
Sustainment: Depot maintenance      support, aeromedical, weather reconnaissance, and natural disaster relief.
conducted at Warner Robins Air      The C-130J is the latest addition to the C-130 fleet.
Logistics Complex, Georgia
                                    Life Cycle of the C-130J
Program Office: Robins Air Force
Base, Georgia and Wright-
Patterson Air Force Base, Dayton,
Ohio
Fiscal Year 2019 Data
Average age: 9.2 years
                                    Note: According to program officials there is not a projected sunset date for this aircraft.
Average lifetime flying hours:
7,626 hours per aircraft            Overview
Depot maintenance activity          From fiscal years 2011 through 2019, the C-130J fleet met or exceeded its
and squadron locations:             annual aircraft availability goals in 4 of the 9 fiscal years, but did not meet
                                    any of its mission capable goals. Both rates decreased slightly during the
                                    time period. Total operating and support (O&S) costs for the C-130J fleet
                                    increased from about $797.34 million to $1.14 billion from fiscal years 2011
                                    through 2018. Unit level manpower costs and maintenance costs increased
                                    the most. Over the 8-year period, the size of the C-130J fleet size increased
                                    from 71 to 120 aircraft due to continued procurement and deliveries of
                                    aircraft. The total O&S cost per aircraft decreased from $11.23 million in
                                    fiscal year 2011 to $9.53 million in fiscal year 2018, while the maintenance
                                    costs per aircraft increased from $2.38 to $3.26 million during the same time
                                    frame.

                                    C-130J Sustainment Status




Sustainment Challenges
and Mitigation Actions
The C-130J faces increasing
maintenance requirements and
parts obsolescence. Mitigation
actions include initiatives to
reduce unscheduled maintenance
and scheduled maintenance and a
program to address diminishing
manufacturing sources and
material shortages.




Page 82                                                                                    GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The April 2015 C-130J Life-Cycle Sustainment Plan establishes the sustainment approach for the operations
   and support phase of the C-130J aircraft. Air Force officials said they expect to complete the development of a
   single, updated life-cycle sustainment plan for both the C-130H and C-130J aircraft in fiscal year 2020.

•   Programmed depot maintenance for the C-130J fleet is conducted by the Air Force at Warner Robins Air
    Logistics Complex, Georgia. However, engine and propeller maintenance is managed by the Rolls-Royce
    Company under a performance based logistics contract, according to C-130 program officials. The Air Force
    Sustainment Center and the Defense Logistics Agency manage the C-130J parts that are common to the C-
    130H aircraft and other DOD programs. Lockheed Martin Aerospace provides supply support for unique C-130J
    components under a performance-based logistics contract.

•   The Air Force sustains the C-130J fleet through programmed depot maintenance, which is initially performed
    after 12 years and then on a recurring 6-year cycle, and through modifications, according to officials.


 Availability and Condition
From fiscal years 2011 through 2019, the C-130J fleet met its annual aircraft availability goals in 4 of the 9 fiscal
years, but did not meet any of its annual mission capable goals. Both the aircraft availability and the mission
capability rates decreased slightly during the time period. According to Air Force officials, the aircraft availability rate
decline was largely due to an increase in the amount of time the aircraft spent in depot maintenance. The officials
said that depot inductions increased 400 percent overall and the associated downtime increased by 436 percent
mostly due to the aircraft’s procurement history and programmed depot maintenance schedule. Older aircraft began
to require recurring maintenance as newer aircraft continued to receive the initial maintenance.

The C-130J’s rates increased slightly for not mission capable maintenance (NMCM) and not mission capable both
(NMCB) from fiscal years 2011 through 2019, while it’s not mission capable supply (NMCS) rate was about the
same at the beginning and the end of the time period. According to Air Force officials, the NMCM rate increases
during this period were due, in part, to unit structure changes. C-130H units needed to train and equip their
maintainers to work on the C-130J. During training, there were not enough qualified maintainers available to repair
C-130J aircraft. Additionally, the officials said that the NMCS and the NMCB increases occurred because the fleet
size was increasing and because the levels of spare parts that were available to maintain the aircraft were
inadequate due to program funding levels. Specific details on mission capable and not mission capable rates were
omitted because the information was deemed by DOD to be sensitive.

 Operating and Support Costs
From fiscal year 2011 through 2018, the total O&S costs for the C-130J fleet increased by about $345.92 million,
from $797.34 million to $1.14 billion. Most of the increase during this time frame occurred in two cost categories:
maintenance and unit-level manpower. Maintenance costs increased by $222.69 million, from $168.73 to $391.42
million, and unit-level manpower costs increased by $144.28 million, from $310.00 to $454.28 million. According to
Air Force officials, the increase in C-130J O&S costs was due, in part, to the addition of aircraft to the fleet. The C-
130J fleet size increased by 49 aircraft, from 71 aircraft in fiscal year 2011 to 120 aircraft in fiscal year 2018.
Further, the officials said that the annual C-130J flight hours increased by about 42 percent during this time frame. A
C-130 program official stated that maintenance costs also increased because the number of aircraft that received
programmed depot maintenance began to double as older aircraft started to require the recurring maintenance
inspection as newer aircraft continued to receive the initial maintenance inspection, among other reasons.




Page 83                                                                             GAO-21-101SP Weapon System Sustainment
C-130J Total Operating and Support Costs




The total O&S costs per C-130J aircraft decreased from $11.23 million to $9.53 million from fiscal year 2011 through
fiscal year 2018. Maintenance costs per C-130J aircraft increased from $2.38 million to $3.26 million during the
same time frame. As noted earlier, the C-130J fleet increased by 49 aircraft and total O&S costs increased by
$345.92 million, from fiscal years 2011 through 2018, and the total O&S cost per aircraft decreased. However, the
maintenance costs increase of $222.69 million, or 132 percent, during that time frame resulted in higher
maintenance costs per C-130J aircraft. Air Force officials attributed the rise in maintenance costs per aircraft to
additional maintenance requirements and associated depot maintenance time, noting that the average time for
programmed depot maintenance went from 129 days in fiscal year 2011 to 220 days in fiscal year 2018. They cited
the replacement of the center wing, the removal of paint, and the modification of an infrared missile
countermeasures system as several examples of activities that were added to the basic maintenance work package
during the 8-year period.




Page 84                                                                       GAO-21-101SP Weapon System Sustainment
C-130J Operating and Support Costs per Aircraft and Fleet Size




 Sustainment Challenges and Mitigation Actions
Maintenance: According to Air Force officials, the C-130J fleet is experiencing sustainment challenges that are
common to all aging aircraft fleets, such as corrosion, structural fatigue, and parts obsolescence. These issues led
to an increase in both field-level and depot-level maintenance, which are being addressed through a series of
maintenance and engineering initiatives. Within the maintenance communities, officials explained that technicians,
led by the Air Mobility Command, continually evaluate the methods for management of maintenance to reduce the
overall downtime. Within the engineering community, continuous analysis is performed to evaluate the effect of flight
operations and maintenance activities on the fleet, according to officials. The officials said they are currently
implementing condition based maintenance initiatives to provide a predictive parts failure replacement program
intended to reduce unscheduled maintenance by converting unscheduled maintenance to scheduled maintenance.
They said they are also working on programmed depot maintenance process improvements and regionalizing
scheduled maintenance inspections to reduce flow days and aircraft downtime.

Supply Support: Air Force officials said that the sustainment challenges faced by the aging C-130H fleet also
resulted in an increase in parts support requirements and a corresponding increase in diminishing manufacturing
sources and material shortages. According to officials, the C-130 program office has an active diminishing
manufacturing sources and material shortages program that was started in 2015 to address both production and
sustainment-supply support issues. C-130 personnel at both Robins Air Force Base and Wright-Patterson Air Force
Base participate in broader Air Force Material Command parts efforts to identify and resolve these issues for the
C-130J fleet.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 85                                                                        GAO-21-101SP Weapon System Sustainment
Page 86   GAO-21-101SP Weapon System Sustainment
                                      E-2C Hawkeye Early Warning and Control Aircraft
                                      Sustainment Quick Look
                                      Common Name: E-2C
                                      Lead Service: Navy

Program Essentials                    Background
Manufacturer: Northrop                The E-2C Hawkeye Early Warning and Control Aircraft is the Navy’s all-
Grumman Aerospace Corporation         weather, carrier-based, tactical battle management, and airborne early
                                      warning, command and control aircraft. The E-2C has a planned sunset date
Sustainment: Depot maintenance        of 2026, when the last of its replacement aircraft, the E-2D Advanced
conducted at Navy Fleet               Hawkeye Early Warning and Control Aircraft, is delivered.
Readiness Centers and field
maintenance conducted by Navy         Life Cycle of the E-2C
maintainers
Program Office: Program
Manager–Air 231, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 17.4 years
Average lifetime flying hours:        Overview
6,105 hours per aircraft              The E-2C did not meet any of its annual mission capable goals from fiscal
Depot maintenance activity            years 2011 through 2019, and the mission capable rate decreased during
and squadron locations:               this time period. According to Navy officials, the E-2C’s mission capable rate
                                      decrease was due to the fleet’s need for additional maintenance as the
                                      aircraft ages. Total operating and support (O&S) costs decreased, from about
                                      $551.85 million in fiscal year 2011 to about $297.66 million in fiscal year
                                      2018, in part because the E-2C inventory is decreasing as Navy squadrons
                                      transition from the E-2C to the E-2D aircraft. During this same time period,
                                      the annual O&S costs per aircraft decreased from about $9.51 million to
                                      about $8.04 million.

                                      E-2C Sustainment Status




Sustainment Challenges
and Mitigation Actions
The E-2C is operating beyond its
planned service life, with
maintenance and supply
challenges. The Navy’s actions to
mitigate these challenges include
transitioning the fleet to the E-2D
aircraft and cannibalizing parts—
that is, moving parts from one
aircraft to another.


Page 87                                                                       GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The E-2C Hawkeye Post Production Support Plan (2011) documents the sustainment logistics, engineering
   programs, and financial resources necessary to ensure the platform’s continued sustainment and attainment of
   readiness and safety operations. According to officials, they will include an appendix for the E-2C when they
   update the sustainment strategy for the E-2D in 2020.

•   The E-2C is maintained organically by field maintainers and at Navy Fleet Readiness Centers Southwest and
    Mid-Atlantic under a planned maintenance interval cycle. Field maintainers perform the initial planned
    maintenance interval 42 months after initial deployment. The Fleet Readiness Centers then perform the second
    cycle of planned maintenance 46 months later.


 Availability and Condition
The E-2C fleet did not meet any of its annual mission capable goals from fiscal year 2011 through fiscal year 2019,
and its mission capable rate decreased. According to program officials, the funding levels for the E-2C did not
support the program’s ability to reach the mission capable goals during the time period. Specifically, E-2 program
officials told us that the funding levels resulted in the cannibalization of parts (i.e., removing serviceable parts from
one aircraft and installing them in another aircraft). However, E-2C officials also stated that the program received
additional funding in fiscal years 2017 through 2019 to support increased readiness, and that if this additional
funding continues, they expect the program can meet the mission capable goal in fiscal year 2021.

The overall decline in the E-2C’s mission capable rate from fiscal years 2011 through 2019 was largely due to
maintenance issues, though supply challenges had an impact in the later years. The not mission capable
maintenance rate was about the same in fiscal year 2011 and fiscal year 2019, but the rate was higher at times in
between these years. The not mission capable supply rate increased from fiscal years 2011 through 2019.
According to officials, these trends are a result of the work that the squadrons recently started to make the
necessary repairs to the E-2C aircraft, and the supply system was not prepared for the increase in parts demand.
Specific details on mission capable and not mission capable rates were omitted because the information was
deemed by DOD to be sensitive.

 Operating and Support Costs
The E-2C’s total O&S costs decreased by about $254.19 million—or 46 percent—from fiscal years 2011 through
2018, in part because the number of aircraft in use also decreased. Specifically, during this time frame, unit level
manpower decreased from about $182 million to about $107 million; and maintenance decreased from about $242
million to about $136 million. According to officials, decreases in costs can be attributed to the transition of the fleet
from the E-2C to the E-2D. Depot maintenance was the most significant contributor to maintenance costs, averaging
about $56.82 million per year, or 30 percent of the total annual maintenance costs from fiscal years 2011 through
2018. The other maintenance cost category was the smallest share, averaging about $10.83 million per year, or 6
percent of the total annual maintenance costs during the same time period.




Page 88                                                                            GAO-21-101SP Weapon System Sustainment
E-2C Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the E-2C’s O&S costs per aircraft generally decreased from about
$9.51 million to about $8.04 million, while the mission capable rate also decreased. Maintenance costs per aircraft,
on average, accounted for almost half of the total O&S costs per aircraft, averaging about $3.92 million per year.
Additionally, the number of aircraft contributing to the costs per aircraft decreased from 58 in fiscal year 2011 to 37
in fiscal year 2018, as the E-2C aircraft transition out of service.




Page 89                                                                           GAO-21-101SP Weapon System Sustainment
E-2C Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: According to Navy officials, the oldest active E-2C aircraft is about 30 years old and the newest is about 10
years old; thus, there is a wide variance in the age of the aircraft. Navy officials also told us there is high demand for
these low-inventory aircraft because of their unique mission capabilities for supporting the Navy’s mission.
According to officials, the Navy is transitioning its E-2C squadrons to the replacement E-2D aircraft and permanently
transitioning the E-2C out of service.

Maintenance: As the E-2C ages, it is requiring additional maintenance for repairs that were not originally planned.
Also, according to officials, maintenance for these aircraft is taking longer because more parts have to be repaired
and replaced and the Navy faces a shortage of depot and field maintenance personnel, due to attrition and inability
to find skilled depot artisans. To address these challenges while the fleet transitions from the E-2C to the E-2D
aircraft, officials said that the Navy has several ongoing and planned actions. These include conducting system
performance studies to identify maintenance tasks to mitigate potential failures; identifying all parts and components
that have to be repaired and replaced during the inspection phase; training depot and field maintainers and other
personnel to be proficient in repairing all parts of the aircraft; and allowing depot and field maintainers to work
overtime to keep up with maintenance schedules.

Supply Support: The E-2C is experiencing shortages of some parts because vendors are no longer producing
these parts. The Navy’s ongoing and planned actions, according to officials, include locating another vendor source,
upgrading hardware and software, reverse engineering, cannibalizing parts, or waiting until the part is available.


Program Office Comments
The program office reviewed a draft of this assessment and did not have any comments.




Page 90                                                                            GAO-21-101SP Weapon System Sustainment
                                     E-2D Advanced Hawkeye Early Warning and
                                     Control Aircraft Sustainment Quick Look
                                     Common Name: E-2D
                                     Lead Service: Navy

Program Essentials                   Background
Manufacturer: Northrop               The E-2D Advanced Hawkeye Early Warning and Control Aircraft is the
Grumman Aerospace Corporation        newest variant of the E-2 aircraft platform, expected to reach full operational
Sustainment: Depot maintenance       capability by 2027. The E-2D aircraft is used to provide advanced warning of
conducted at Navy Fleet              approaching enemy surface units and aircraft, among other things.
Readiness Centers and field
maintenance provided by Navy         Life Cycle of the E-2D
maintainers
Program Office: Program
Manager–Air 231, Naval Air
Systems Command, Patuxent
River, Maryland
 Fiscal Year 2019 Data
Average age: 4.6 years
Average lifetime flying hours:       Overview
1,427 hours per aircraft             The E-2D fleet did not meet its annual mission capable goals from fiscal year
Depot maintenance activity           2014 through fiscal year 2019, and its mission capable rate decreased during
and squadron locations:              this time period. 1 Total operating and support (O&S) costs consistently
                                     increased, from zero in fiscal year 2011 to about $228.75 million in fiscal year
                                     2018. According to officials, the rising O&S costs were largely due to the
                                     procurement of additional aircraft. The E-2D fleet increased from three
                                     aircraft in fiscal year 2011 to 26 aircraft in fiscal year 2018. In fiscal year
                                     2018, the O&S cost per E-2D aircraft was about $8.8 million, with over a third
                                     of the costs dedicated to maintenance needs.

                                     E-2D Sustainment Status




Sustainment Challenges
and Mitigation Actions
The E-2D faces maintenance and
supply challenges. The Navy’s
actions to mitigate these
challenges include troubleshooting
component failures and
cannnibalizing parts—that is,
moving parts from one aircraft to
another.


                                     1According   to Navy officials, mission capable data was not available for the E-2D until
                                     fiscal year 2014, when the aircraft entered the fleet.



Page 91                                                                              GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The E-2D Advanced Hawkeye Acquisition Category ID Life-Cycle Sustainment Plan (2012) describes the Navy’s
   approach to sustaining the E-2D aircraft. Also, it describes the overall plan for the management and execution of
   the product support package by communicating the sustainment strategy to stakeholders in the acquisition,
   engineering, and logistics communities. Navy officials said they expect to issue an updated life-cycle
   sustainment plan in 2020.

•   Currently, supply support is provided organically by Naval Supply Systems Command and the Defense Logistics
    Agency; contractor support services are provided by Northrop Grumman Systems Corporation-Aerospace
    Systems. According to officials, the E-2D’s depot maintenance is conducted at the Navy Fleet Readiness Center
    – Southwest, under a planned maintenance interval cycle of 44 months.


 Availability and Condition
From fiscal year 2014 through fiscal year 2019, the E-2D fleet did not meet its annual mission capable goals and its
mission capable rate decreased during the time period. 2 According to program officials, prior to fiscal year 2019 the
E-2D program did not focus on the fleet-wide mission capable rate as the main metric for the fleet. Under metrics
emphasized previously, the E-2D program prioritized resources to units based on training and deployment cycles
instead of fleet-wide readiness measures.

The decrease in the E-2D’s mission capable rate from fiscal years 2014 through 2019 was due to an increase in the
percent of aircraft that were not mission capable for maintenance (NMCM) and not mission capable for supply
(NMCS). The rates increased for NMCM and NMCS by almost the same amount during this time period. According
to program officials, the NMCM rate increase was due to an increase in inspections and maintenance needs for the
aircraft, while the increase in NMCS was a result of inadequate spares funding for the initial outfitting of the aircraft
and the cannibalization of parts from other E-2D aircraft. Specific details on mission capable and not mission
capable rates were omitted because the information was deemed by DOD to be sensitive.

 Operating and Support Costs
From fiscal year 2011 through 2018, the total O&S costs for the E-2D aircraft increased consistently, from zero to
about $228.75 million, with maintenance and unit level manpower costs increasing the most. According to officials,
O&S cost growth was mostly due to the procurement of additional aircraft, additional E-2D squadrons, and
deployments. Depot-level reparables were the most significant contributor to maintenance costs, averaging about
$15.29 million per year during the period.




2 According to Navy officials, mission capable data was not available for the E-2D until fiscal year 2014, when the aircraft entered the
fleet.

Page 92                                                                                       GAO-21-101SP Weapon System Sustainment
E-2D Total Operating and Support Costs




From fiscal year 2012 through fiscal year 2018, the E-2D’s O&S costs per aircraft increased to about $8.80 million.
Maintenance costs per aircraft was 38 percent of the total O&S costs per aircraft in fiscal year 2018. As noted
earlier, the E-2D fleet did not incur O&S costs in fiscal year 2011, and total O&S costs increased to about $228.75
million in fiscal year 2018. Additionally, the number of aircraft contributing to the cost per aircraft increased from
three in fiscal year 2011 to 26 in fiscal year 2018, with a total expected fleet of 75 aircraft.




Page 93                                                                          GAO-21-101SP Weapon System Sustainment
E-2D Maintenance and Other Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Maintenance: According to officials, some components of the E-2D are experiencing faster failure rates than
originally planned, resulting in increased maintenance requirements of the aircraft. Officials told us that the avionics
system on the E-2D is much heavier than the airframe can support, resulting in additional weight and balance
checks as well as airframe maintenance issues. Also, there is high demand for these low-inventory aircraft because
of the unique mission capabilities of these aircraft, which has resulted in increased maintenance repairs. Also, there
is a shortage of depot and field maintenance personnel due to attrition and inability to find skilled depot artisans. The
Navy’s ongoing and planned actions, according to officials, include performing weight and balance checks during
maintenance repairs, having original equipment manufacturers troubleshoot component failures, identifying all parts
and components that need to be repaired and replaced during the inspection phase, moving maintainers around to
squadrons as their skill set is needed, and allowing maintainers to work overtime to keep up with maintenance
schedules.

Supply Support: E-2D officials said that the aircraft is experiencing some parts shortages because the vendors
stopped producing the parts. Even though the E-2D is still in production, in some cases there is not enough demand
for manufacturers to keep production lines open in order to continue making spare parts or to propose redesigns of
parts. The Navy’s ongoing and planned actions, according to officials, include locating another vendor source,
hardware and software upgrades, performing maintenance practices to determine whether a part is reusable before
ordering a new part, cannibalizing parts (i.e., removing serviceable parts from one aircraft and installing them in
another aircraft), or waiting until the part is available.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 94                                                                           GAO-21-101SP Weapon System Sustainment
                                     E-6B Mercury Sustainment Quick Look
                                     Common Name: E-6B
                                     Lead Service: Navy

                                     Background
Program Essentials                   The E-6B Mercury is used to link the National Command Authority (NCA)
                                     with naval ballistic missile forces during times of crisis, often referred to as
Manufacturer: Boeing
                                     the Take Charge and Move Out mission. The E-6B was derived from
Sustainment: Organizational level    Boeing’s commercial 707 and is intended to provide survivable, reliable, and
maintenance is conducted by          endurable airborne command, control, and communications between the
Navy personnel, and depot-level      NCA and U.S. strategic and non-strategic forces. The Navy plans to use the
maintenance at Oklahoma City Air     aircraft until 2038.
Logistics Complex, Oklahoma
                                     Life Cycle of the E-6B
Program Office: Program
Manager – Air 271, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 26.64 years
Average lifetime flying hours:
                                     Overview
24,442 hours per aircraft
                                     The E-6B fleet met or exceeded its annual mission capable goals for 5 of the
Depot maintenance activity           9 fiscal years from fiscal years 2011 through 2019 and its mission capable
and squadron locations:              rate decreased during this time period. Program officials cited three reasons
                                     for not meeting the mission capable goals: parts obsolescence, aging aircraft,
                                     and increased maintenance needs. Total operating and support (O&S) costs
                                     remained relatively stable over the past 8 years, ranging from $423 to $517
                                     million, with $489 million spent in 2018. However, total O&S costs per aircraft
                                     increased during this same time period. Specifically, total O&S costs per
                                     aircraft increased from $29.83 million in fiscal year 2011 to $34.95 million in
                                     fiscal year 2018. Further, total maintenance costs per aircraft also increased,
                                     from $5.42 million in fiscal year 2011 to $9.28 million in fiscal year 2018.
                                     Officials stated that increasing the lifespan of the aircraft has created more
                                     requirements on maintenance personnel, and total maintenance hours have
                                     increased by 9 percent since 2010.

                                     E-6B Sustainment Status



Sustainment Challenges
and Mitigation Actions
The E-6B faces sustainment
challenges related to aging,
including parts obsolescence and
increased maintenance needs.
The program office has initiatives
to address these issues, including
a spare parts initiative.




Page 95                                                                        GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The Life-Cycle Sustainment Plan for the E-6B Block I Low Rate Initial Production Program was issued in 2011
   and provides general information and a description of the overall logistics support required for the program’s
   equipment. The E-6B Block I Modification program will correct follow-on operational test and evaluation
   deficiencies, including reliability and maintainability. Improvements will include upgrades to communication
   systems, aircraft cooling systems, and workstations for crew.


Availability and Condition
The E-6B fleet met or exceeded its annual mission capable goals for 5 of the 9 fiscal years from fiscal years 2011
through 2019 and its mission capable rate decreased during this time period. Program officials attributed the drop in
the mission capable rate to a change in the Navy’s method for calculating the mission capable rate, parts
obsolescence and diminishing repair and manufacturing sources; aging aircraft; and increased levels of
maintenance. Officials stated that parts are becoming physically obsolete and that fewer repair and manufacturer
vendors exist or have the equipment to repair or manufacture parts.

From fiscal years 2011 through 2019, the E-6B’s rates increased for not mission capable depot, not mission capable
maintenance (NMCM), and not mission capable supply. According to officials, the increase in the NMCM rate was
due to the increased maintenance requirements of the aging aircraft. Specific details on mission capable and not
mission capable rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
Total O&S costs for the E-6B increased from $447.45 million in fiscal year 2011 to $489.34 million in fiscal year
2018. Maintenance costs increased significantly, from $81.26 million in fiscal year 2011 to $129.92 million in fiscal
year 2018. The largest driver of maintenance costs was depot maintenance, increasing from $39.05 million in fiscal
year 2011 to $75.07 million in fiscal year 2018. According to program officials, maintenance has increased to keep
up with the needs of an aging aircraft.




Page 96                                                                         GAO-21-101SP Weapon System Sustainment
E-6B Total Operating and Support Costs




O&S costs per aircraft for the E-6B increased since fiscal year 2011. Specifically, total O&S costs per aircraft were
$29.83 million in fiscal year 2011 and $30.58 million in fiscal year 2018. Further, maintenance costs per aircraft
increased from $5.42 million in fiscal year 2011 to $8.12 million in fiscal year 2018. These increases occurred while
the number of aircraft remained stable.




Page 97                                                                         GAO-21-101SP Weapon System Sustainment
E-6B Maintenance and Other Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: Program officials told us that the Navy recently increased the lifespan of the E-6B from 27,000 hours to
45,000 hours. The average age of the aircraft in fiscal year 2019 was 26.64 years, with average flying hours of
24,442 per aircraft. The Navy plans for the aircraft to be operating until 2038.

Maintenance: Increasing the service life of the aircraft from 2024 to 2038 has created more requirements on the
squadron maintenance personnel. For example, total maintenance work hours conducted on the aircraft have
increased by 9 percent since 2010. Mitigation actions include a maintenance work-hour reduction effort that includes
examining maintenance requirements and adjusting them based on engineering analysis and failure data.
Additionally, the Navy conducted an analysis that showed that hard landing limits could be increased without
concern for the safety of the aircraft or the integrity of its landing gear. This will reduce maintenance requirements,
such as the number of inspections, and will allow for maintenance personnel to be focused on other issues.

Supply: As the aircraft ages, parts have become more difficult to replace because components are becoming
physically obsolete and fewer repair and manufacturer vendors exist or have the equipment to repair or manufacture
parts. The program office has undertaken several actions to improve supply, including analyzing the status of parts
not currently available in inventory, to identify milestones and track progress so as to return these parts to a healthy
inventory status; developing a spare parts requirement tied to the service life extension to 2038 for the aircraft; and
ensuring that the contractor for logistics support has adequate personnel to execute increased supply demands.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 98                                                                          GAO-21-101SP Weapon System Sustainment
                                    E-3 Sentry Airborne Warning and Control System
                                    (AWACS) Sustainment Quick Look
                                    Common Name: AWACS
                                    Lead Service: Air Force

Program Essentials                  Background
Manufacturer: Boeing                The E-3 Sentry AWACS aircraft was first manufactured in 1971. It is an
Sustainment: Depot maintenance      airborne warning and control system that may be employed alone or in
conducted at Oklahoma City Air      combination with other command and control battle management,
Logistics Complex, Oklahoma,        intelligence, surveillance, and reconnaissance systems.
and field maintenance conducted
by Air Force maintainers            Life Cycle of the E-3

Program Office: Tinker Air Force
Base, Oklahoma, and Hanscom
Air Force Base, Massachusetts
Fiscal Year 2019 Data
Average age: 40 years
Average lifetime flying hours:      Overview
28,649 hours per aircraft
                                    From fiscal years 2011 through 2019, the E-3 fleet did not meet any of its
Depot maintenance activity          annual aircraft availability goals, but met or exceeded its mission capable
and squadron locations:             goals during 3 of the 9 fiscal years. The E-3’s aircraft availability rate slightly
                                    decreased during the time period while its mission capable rate slightly
                                    increased. Total operating and support (O&S) costs decreased from about
                                    $1.11 billion in fiscal year 2011 to about $816.26 million in fiscal year 2018,
                                    due in part to significant decreases in unit operations and continuing system
                                    improvement costs. During this same time period, the annual O&S costs per
                                    aircraft decreased from $34.54 million to $26.33 million. On average,
                                    maintenance costs per aircraft accounted for about 22 percent of the total
                                    costs per aircraft.

                                    E-3 Sustainment Status




Sustainment Challenges
and Mitigation Actions
The E-3 faces sustainment
challenges related to supply of
needed parts and maintenance of
the aging aircraft. The program
office is working to increase the
availability of parts and has
implemented initiatives to
modernize the aircraft.




Page 99                                                                        GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The Air Force is implementing the Diminishing Manufacturing Sources Replacement of Avionics for Global
   Operations and Navigation (DRAGON) program to replace the E-3’s aging, predominantly analog, non-
   sustainable avionics equipment with modern, widely available, and commercially derived digital systems in an
   effort to enhance operation, safety, and reliability while reducing life-cycle costs. The program is designed to
   utilize parts currently used by commercial air carriers or existing military aircraft. Program officials expect the
   cost, schedule, and technical risk—including reliability risk—of the program to be minimal. Planned
   maintenance, field maintenance, and inspection processes will continue with the infrastructure currently in place.

•   The Life-Cycle Sustainment Plan for DRAGON states that the program will initially rely on an interim contractor-
    support contract with Boeing—for one year, with two one-year options—for item management and depot
    maintenance of components and support equipment, and will later transition to contractor logistics support. The
    plan states that once sufficient aircraft have been modified and flown operationally, then those sustainment data
    can be used to decide whether to maintain the contractor logistics support or, alternatively, to choose a different
    sustainment approach. Beginning in January 2021, sustainment will transition to Air Force maintainers,
    contractor logistics support, or a combination of both. Additionally, depot repairs for the E-3 may be performed
    in-house, by contractor or a public-private partnership, to ensure that the appropriate cost-effective product
    support is provided.


 Availability and Condition
The E-3 fleet did not meet its aircraft availability goals from fiscal years 2011 through 2019, but met its mission
capable goals during 3 of the 9 fiscal years. The E-3’s aircraft availability rate slightly decreased during the time
period while the mission capable rate slightly increased. According to Air Force officials, the primary reason for the
drop in aircraft availability was the current and planned modifications for the E-3 fleet. The E-3’s mission capable
rate was slightly higher in fiscal year 2019 than it was in fiscal year 2011. However, program officials said there were
challenges and circumstances during these years affecting mission capability.

From fiscal year 2011 through fiscal year 2019, the E-3 not mission capable maintenance rate slightly increased;
while the rate slightly decreased for not mission capable supply. The not mission capable both (NMCB)
maintenance and supply rate in fiscal year 2019 was less than one percent below the fiscal year 2011 rate. Program
officials stated that these rates were due to an increased number of repairs, over the same period of time, occurring
on various aircraft systems (i.e., the fuel system, landing gear, airframe, air conditioning pressurization, and turbofan
power plant). Further, officials noted that the degraded reliability of aircraft systems could also have caused an
increase in maintenance actions. Specific details on mission capable and not mission capable rates were omitted
because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the E-3’s total O&S costs decreased, from about $1.11 billion to
about $816.26 million, due to significant decreases in unit operations and continuing system improvement costs.
Maintenance costs constituted the second largest O&S cost category behind unit level manpower and accounted for
22 percent of total O&S costs from fiscal years 2011 through 2018, averaging about $223.66 million per year. Depot
maintenance costs fluctuated over this period and were the most significant contributor to maintenance costs,
representing 55 percent of the total maintenance costs. According to officials, depot maintenance costs fluctuated
based on the number of programmed and unscheduled depot maintenance, the quantity of engines requiring
overhaul per year, depot maintenance sales rates, and the software maintenance workload.




Page 100                                                                          GAO-21-101SP Weapon System Sustainment
E-3 Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the O&S costs per E-3 aircraft generally decreased, from about
$34.54 million to about $26.33 million. Maintenance costs per aircraft decreased from about $6.97 million to about
$6.32 million (or about 24 percent) of total O&S costs per aircraft during this same time period.




Page 101                                                                       GAO-21-101SP Weapon System Sustainment
E-3 Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging and Maintenance: According to program officials, the E-3 is prone to corrosion, stress corrosion, and fatigue
damage. Program officials stated that the aircraft is inspected for this damage, and repairs are completed when
needed. Officials also noted that the systems on the aircraft are aging and require additional maintenance to restore
mission capability. Additionally, program officials have found several components for which more detailed overhaul
or even new parts are required. Further, program officials stated that depot maintenance of the E-3 airframe
(conducted on a 5-year depot cycle), engines, and much of the software is sustained by Air Force maintainers.

Supply Support: Diminishing manufacturing sources will continue to be an ongoing sustainment challenge across
the E-3 platform. According to program officials, it is common for contractors not to want to restart production of
parts for small quantities. Officials stated that they work closely with the supply chain to resolve these issues when
they occur. Further, the program officials noted that the E-3 engine suffers from “cold” supply chains; specifically, no
commercial vendors have made some parts for several years. As a result, officials stated that the Propulsion
Sustainment Division is seeking expanded ability to address this situation through an Integrated Product Team that
is working to reinvigorate the industrial base by visiting vendors to encourage open competition for new parts.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 102                                                                         GAO-21-101SP Weapon System Sustainment
                                        E-4B Sustainment Quick Look
                                        Common Name: E-4B
                                        Lead Service: Air Force

                                        Background
Program Essentials                      The E-4B serves as the National Airborne Operations Center and is a key
Manufacturer: Boeing                    component of the National Military Command System for the President, the
                                        Secretary of Defense, and the Joint Chiefs of Staff. In case of national
Sustainment: Depot maintenance          emergency or destruction of ground command and control centers, the
is conducted by contractor              aircraft provides a highly survivable command, control, and communications
logistics support, with some            center to direct U.S. forces, execute emergency war orders, and coordinate
organizational level maintenance        actions by civil authorities. The E-4B is a militarized version of the Boeing
conducted by the Air Force              747-200 that was declared fully operational in 1985. To provide direct support
Program Office: Tinker Air Force        to the President, the Secretary of Defense, and the Joint Chiefs of Staff, at
Base, Oklahoma                          least one E-4B is always on 24-hour alert, 7 days a week, with a global watch
                                        team at one of many selected bases throughout the world.
Fiscal Year 2019 Data
                                        Life Cycle of the E-4B
Average age: 45 years
Average lifetime flying hours:
18,557 hours per aircraft
Depot maintenance activity
and squadron locations:


                                        Overview
                                        From fiscal years 2011 through 2019, the E-4B fleet did not meet any of its
                                        annual aircraft availability goals, but met or exceeded its mission capability
                                        goal in 3 of the 9 fiscal years. The E-4B’s aircraft availability rate was almost
                                        the same in fiscal years 2011 and 2019 and its mission capable rate
                                        decreased during the time period. Total operating and support (O&S) costs
                                        increased since fiscal year 2011, from $298.95 million to about $341.37
                                        million in fiscal year 2018. Maintenance costs also increased during this time
                                        period, from $116.02 million in fiscal year 2011 to $168.36 million in fiscal
                                        year 2018. According to program officials, these increases were due to the
                                        aging of the aircraft. Per aircraft total O&S costs increased from $74.74
                                        million in fiscal year 2011 to $85.34 million in fiscal year 2018.
Sustainment Challenges                  E-4B Sustainment Status
and Mitigation Actions
The E-4B faces sustainment
challenges due to its age, making
it more difficult to find replacement
parts. In addition, delays in
scheduled programmed depot
maintenance has reduced
operational availability.




Page 103                                                                          GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The E-4B’s Life-Cycle Sustainment Plan (April 2019) focuses on meeting the needs of the Air Force Global
   Strike Command as well as additional missions defined by the Chairman of the Joint Chiefs of Staff. The plan
   includes modifications periodically required to ensure the ability of the aircraft to support these missions.

•   Organizational level maintenance for the E-4B is augmented by limited contractor repair capabilities, and depot-
    level maintenance is performed by Boeing. An integrated supply chain management system with a centralized
    inventory supports this fleet’s requirements through supply points at the main operating base (Offutt Air Force
    Base, Nebraska) and the depot facility (San Antonio, Texas) for the aircraft.


Availability and Condition
From fiscal years 2011 through 2019, the E-4B fleet did not meet any of its annual aircraft availability goals, but met
or exceeded its mission capability goal in 3 of the 9 fiscal years. According to the program office, there are several
challenges to meeting the aircraft availability goal, including the small size of the fleet and downtime to conduct
modifications on the aircraft. Aircraft availability for the E-4B in fiscal year 2019 was about the same as it was in
fiscal year 2011. The E-4B’s mission capable rate decreased from fiscal years 2011 through 2019, but fluctuated
over the time period.

The primary driver of the E-4B’s mission capable rate was maintenance. The E-4B’s not mission capable
maintenance rate increased from fiscal years 2011 through 2019, but was variable during the time period and the
not mission capable both maintenance and supply rate increased. The small size of the fleet contributed to the
maintenance issues of the E-4B because one aircraft taken down for maintenance has a proportionally greater
effect on the percentage of aircraft available for operations than it would for a larger fleet. Specific details on mission
capable and not mission capable rates were omitted because the information was deemed by DOD to be sensitive.


Operating and Support Costs
Total O&S costs for the E-4B rose by about 14 percent from fiscal year 2011 through fiscal year 2018, with
maintenance costs accounting for about 49 percent of total O&S costs in fiscal year 2018.




Page 104                                                                           GAO-21-101SP Weapon System Sustainment
E-4B Total Operating and Support Costs




Per aircraft total O&S costs for the E-4B increased from $74.74 million in fiscal year 2011 to $85.34 million in fiscal
year 2018. In addition, per aircraft maintenance costs increased from $29.01 million in fiscal year 2011 to $42.09
million in fiscal year 2018. The number of aircraft during this time period remained steady at four total aircraft.




Page 105                                                                          GAO-21-101SP Weapon System Sustainment
E-4B Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Supply: Due to the age of the aircraft, certain parts are getting older and more difficult to replace. For example,
according to the program office, flight deck gauge failures are increasing, and the replacement parts are difficult to
find. The program office is working to find new manufacturers for these gauges. Further, the program is working to
identify additional warehouse space to store large spare parts such as flight controls and airframe panels. In
addition, lack of storage for spare parts increases the risk that parts may not be available when needed and could
negatively impact aircraft availability. The program office is currently utilizing space in a base supply facility as a
temporary solution but is working on agreements with other base tenants to gain more storage space.

Maintenance: According to the program office, for the past 2 years the contractor has not completed programmed
depot maintenance within the required time limits, thereby reducing operational availability of the aircraft. Program
officials told us that multiple efforts are underway to reduce maintenance downtime. For example, the program is
initiating incentivized programmed depot maintenance dates that provide monetary incentives to the contractor for
performing work by certain dates. The program office has also developed a 5-year maintenance roadmap that tracks
future maintenance packages, acquisitions, and modifications, and it has added mandatory field-level inspection
requirements every 200 days. In addition, the program office is working to conduct needed modifications to the
aircraft during programmed depot maintenance, including overhauling the landing gear and flight control.


 Program Office Comments
In commenting on a draft of this assessment, the program office stated that historically, E-4B sustainment is
underfunded and must rely on unfunded requirements and end-of-year funding to remain healthy. Further, costs
have risen in previous years due to aircraft age, supplier issues, and natural disaster incidents, and they are
expected to continue to rise throughout the Future Years Defense Program. In addition, the program office stated
that it is executing several initiatives to improve aircraft availability, including programmed depot maintenance pre-
planning and the creation of a systems integration lab.




Page 106                                                                          GAO-21-101SP Weapon System Sustainment
                                       E-8C Joint Surveillance Target Attack Radar
                                       System Sustainment Quick Look
                                       Common Name: JSTARS
                                       Lead Service: Air Force

Program Essentials                     Background
Manufacturer: Northrop                 The E-8C Joint Surveillance Target Attack Radar System was built using pre-
Grumman                                owned Boeing 707-300 aircraft that were first manufactured in 1967. The joint
                                       Air Force and Army system includes airborne radar, operations and control,
Sustainment: Depot maintenance         and communication subsystems, as well as two ground-based subsystems.
conducted by Northrop Grumman,         Its primary mission is to provide theater ground and air commanders with
and field maintenance primarily        ground surveillance to support attack operations and targeting.
conducted by the Air Force
                                       Life Cycle of the E-8C
Program Office: Robins Air Force
Base, Georgia
Fiscal Year 2019 Data
Average age: 51.6 years
Average lifetime flying hours:
60,573 hours per aircraft
Depot maintenance activity             Overview
and squadron locations:
                                       From fiscal years 2011 through 2019, the E-8C fleet did not meet any of its
                                       annual aircraft availability goals and met or exceeded its mission capable
                                       goal in 1 of the 9 fiscal years. The E-8C fleet aircraft availability and mission
                                       capable rates decreased during the time period. Total operating and support
                                       (O&S) costs increased from approximately $722.76 million in fiscal year 2011
                                       to $992 million in fiscal year 2018. All of the O&S cost categories decreased
                                       except maintenance, which increased primarily in the contractor logistics
                                       support cost category. During this same time frame, Northrop Grumman
                                       conducted depot maintenance on the E-8C. The total O&S costs per aircraft
                                       also increased from fiscal years 2011 to 2018, from about $42.51 million to
                                       $62 million. In fiscal year 2018, nearly three-quarters of the total O&S costs
                                       per aircraft, or about $45.94 million, was for aircraft maintenance.

                                       E-8C Sustainment Status


Sustainment Challenges
and Mitigation Actions
The E-8C is an aircraft with
significant maintenance and
supply challenges. Examples of
the Air Force’s actions to mitigate
these challenges include
implementing a new depot
maintenance plan and contracting
with Boeing to redesign the
aircraft’s pylons, which are used to
hold the aircraft’s engines to the
wings, according to Air Force
officials.


Page 107                                                                         GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The Joint Surveillance Target Attack Radar System Life-Cycle Management Plan (2014) documents the
   sustainment plan for the E-8C. Program officials said they will update the life-cycle management plan prior to
   October 2022, when the current Total System Support Responsibility contract with Northrop Grumman ends.
   The current support contract is valued at $7 billion, and $4.4 billion has been obligated through fiscal year 2019,
   according to program office officials.

•   As of May 2020, Northrop Grumman provides depot maintenance and supply chain management of E-8C
    specific items under the previously mentioned contract. In July 2018 the Air Force inducted an E-8C aircraft at
    Warner Robins Air Logistics Complex to demonstrate potential cost and schedule efficiencies from performing
    depot maintenance at an organic, Air Force depot. The complex was approved as a designated source of repair
    for the E-8C in early 2019, according to Air Force officials; however, the Air Force has not decided on its
    approach to providing depot maintenance on the E-8C beyond 2022. The Air Force currently repairs and
    overhauls the E-8C’s TF33 engines at Tinker Air Logistics Complex. Field maintenance is performed primarily by
    active duty Air Force and Air National Guard personnel. The Air Force Sustainment Center and the Defense
    Logistics Agency provide supply support for items common with other Department of Defense weapon systems.

•   Under the current programmed depot maintenance plan that is based on the Boeing 707 commercial
    maintenance plan, one of four areas of the aircraft is inspected and receives depot maintenance every 24
    months, according to Air Force officials. Thus, depot maintenance on the aircraft occurs over a period of about
    12 years. Program officials have determined that this plan is inadequate for the E-8C’s fleet of aging aircraft and
    are implementing a new programmed depot maintenance plan with a 6-year depot maintenance cycle.
    According to the program office officials, the entire aircraft will undergo a nose-to-tail inspection at the 3-year
    point and a depot maintenance event at the 6-year point.


Availability and Condition
From fiscal year 2011 through fiscal year 2019, the E-8C fleet missed its aircraft availability goals every year and
met or exceeded its mission capable goal in 1 of the 9 fiscal years, The E-8C’s aircraft availability rate decreased
during the time period. Air Force officials said that delays in contracted depot maintenance constituted the largest
driver that negatively affected the E-8C fleet’s availability rate. For example, the percentage of the E-8C fleet in
depot maintenance increased from about 28 percent in fiscal year 2011 to about 37 percent in fiscal year 2019. Air
Force officials also explained that the program’s use of the commercial maintenance plan (previously discussed)
and contractor performance issues have contributed to the increased depot maintenance time and reduced aircraft
availability. The E-8C’s mission capable rate also decreased percent from fiscal years 2011 through 2019, and the
engine was the leading degrader of mission capability due to problems with the thrust reversers, capacity-related
maintenance delays, and other maintenance issues.

The E-8C’s rates increased for not mission capable maintenance (NMCM), not mission capable supply (NMCS), and
not mission capable both (NMCB) maintenance and supply from fiscal years 2011 through 2019. The NMCB rate
increased the most, and accounted for almost half of the decrease in the mission capable rate during the time
period. Air Force officials stated that the top E-8C NMCM and NMCS rate drivers for fiscal years 2011 through 2019
were the TF33 engine and the fuel system and they also cited flight controls and scheduled inspections as two other
major not mission capable drivers. Air Force officials explained that the E-8C’s NMCB rate was variable because E-
8C aircraft accumulate most of the NMCB time during scheduled inspections. If an aircraft is not mission capable
and awaiting parts through the supply system and it becomes due for a scheduled inspection, program officials
stated that they have the scheduled inspection performed while the aircraft cannot complete missions due to the
lack of the part. Specific details on mission capable and not mission capable rates were omitted because the
information was deemed by DOD to be sensitive.


 Operating and Support Costs
Total O&S costs increased by about $269.23 million, from approximately $722.76 million in fiscal year 2011 to $992
million in fiscal year 2018. All of the O&S cost categories decreased during the time period except maintenance.
Maintenance costs increased by $460.05 million, from $274.91 million in fiscal year 2011 to $734.96 million in fiscal
year 2018. During that time period, maintenance costs increased primarily in the contractor logistics support
category. In fiscal year 2018, contractor logistics support represented $680.45 million of total maintenance costs—
about 93 percent. Sustainment of the aircraft is performed through contractor logistics support.

Page 108                                                                         GAO-21-101SP Weapon System Sustainment
According to Air Force officials, maintenance costs have increased in part due to the age of the aircraft. As a result,
the officials said that the program has been required to conduct repairs related to corrosion prevention and
mitigation, as well as to perform additional structural repairs that are necessary to keep the aircraft operational.
Program officials also said that using a commercial depot maintenance plan (as previously discussed), increasing
numbers of service bulletins, and maintenance quality inefficiencies (that is, corrections to contractor repairs) also
contributed to higher maintenance costs in recent years, among other reasons.

The E-8C’s costs for unit operations, unit level manpower, continuing systems improvements, and indirect support
decreased from fiscal year 2011 through 2018. Air Force officials stated that one reason why unit level manpower
costs went down is because the E-8C’s operational units have had difficulty filling vacancies, and vacancies have
increased faster than units can fill positions. The costs for continuing systems improvements were lower in fiscal
year 2018 because that was the last year of funding for the prime mission equipment diminishing manufacturing
sources modification, according to Air Force officials.


E-8C Total Operating and Support Costs




Although the E-8C fleet size remained fairly constant, the total O&S costs per E-8C aircraft increased from about
$42.51 million in fiscal year 2011 to about $62 million in fiscal year 2018. During this time period the maintenance
costs per aircraft also increased, from $16.17 million to about $45.94 million. The E-8C inventory was comprised of
17 aircraft in fiscal years 2011 and 2012 and 16 aircraft in fiscal years 2013 through 2018, due to the loss of an
aircraft in 2013.




Page 109                                                                         GAO-21-101SP Weapon System Sustainment
E-8C Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: The E-8C airframe has been in operation commercially since 1967, and corrosion is prevalent with the
system. According to Air Force officials, the military use of the E-8C exposes the fleet to more extreme
circumstances than commercial use, causing corrosion to be more problematic. Further, program officials stated that
the original E-8C Corrosion Prevention and Control Program was based on commercial standards and was
ineffective for sustaining a military weapon system. As a result, program officials began rewriting the E-8C’s
Corrosion Prevention and Control Program in fiscal year 2017 to comply with Air Force standards. The officials
stated that they expected to complete the revised corrosion program by the end of fiscal year 2021. To support the
revised corrosion program, E-8C program officials stated that they executed an engineering services contract in
September 2017 to develop technical data to improve corrosion repair and reduce future corrosion damage with
improved processes and materials. These data were used to develop a new paint specification that program officials
plan to implement on the first aircraft in 2020. The officials explained that the new paint specification applies an
additional protective coating on the leading edges and upper wing surfaces to reduce corrosion damage and
improve the integrity of the paint system between the programmed depot maintenance paint intervals.

Maintenance: According to Air Force officials, the E-8C faces extended downtime and reduced aircraft availability
as a result of contractor depot maintenance delays. To mitigate this issue, E-8C program officials explained that
they have taken the following actions, among others:

•   They developed a collaborative maintenance “speed” line at Warner Robins Air Logistics Complex with Northrop
    Grumman and Boeing to improve repair times for certain structural components in 2018. E-8C program officials
    explained that the Air Force conducted the staging and preparation work for the repairs and Boeing performed
    the structural repair work on the aircraft as a subcontractor to Northrop Grumman. Examples of speed line
    repairs include the body station 360, center wing refurbishment, and wing plank four replacements. According to
    program officials, three aircraft were completed at this maintenance speed line, before it was shut down due to
    capacity constraints at Warner Robins Air Logistics Complex. They are working with Northrop Grumman to re-
    establish the maintenance line at the contractor’s facility.

•   They started an organic depot maintenance proof-of-concept at Warner Robins Air Logistics Complex, with two
    maintenance docks. The first E-8C was inducted for programmed depot maintenance in July 2018 to
    demonstrate potential cost and schedule efficiencies from organic maintenance. The goal was to complete the
    depot maintenance on one of the four designated areas of the aircraft within 300 flow days (that is, calendar
    days) at a cost of $14.5 million. According to Air Force officials, the contractor’s average was 338 flow days for
Page 110                                                                         GAO-21-101SP Weapon System Sustainment
    the depot maintenance on the same area of the aircraft, and in fiscal year 2017 the contractor’s average costs
    across varying depot maintenance events were about $38 million per aircraft. The officials said that as of mid-
    April 2020, the first aircraft was at 639 flow days and had not yet been completed, but the projected cost of the
    depot maintenance was only slightly higher than planned at $14.7 million. They told us that maintenance took
    longer than expected due to challenges associated with the alignment of the pylons to which the engines are
    attached on the aircraft and major structural repairs to the right wing. According to program officials, the repairs
    needed to restore the wing’s structural integrity require parts that must be manufactured and have long material
    lead times; therefore, the repairs are not scheduled to be completed until fiscal year 2021. The program office
    inducted a second E-8C aircraft into depot maintenance at Warner Robins Air Logistics Complex in March 2020,
    which is discussed in more detail below. However, according to the officials, the two maintenance docks at
    Warner Robins Air Logistics Complex are not sufficient to transition the depot maintenance for the entire E-8C
    fleet to the Air Force. To address the capacity issue, program officials said that they requested funding to start
    the construction of additional depot maintenance docks for the E-8C in fiscal year 2023 at Warner Robins Air
    Logistics Complex, but the funding had not yet been approved as of May 2020.

•   They implemented a standard process in 2018 to develop engineering maintenance requirements and ensure
    that the requirements are valid and fully supportable before execution. Program officials said that the contractor
    did not fully utilize this process, but the process is now being used to record the data from depot maintenance
    events occurring at Warner Robins Air Logistics Complex. Specifically, the data generated by the aircraft
    inspections and associated repair activity are recorded and used to continuously review the maintenance
    requirements, according to the officials. Based on the recorded data, maintenance requirements may be added
    to address issues that are found or reduced. As a result of the process, program officials said that the
    maintenance plan will be updated as the needs of the aircraft change, as the weapon system ages.

•   They increased the use of additional inspections beginning in fiscal year 2019 to inform decisions about whether
    to extend the period of time during which an aircraft can fly before the next depot maintenance induction.
    According to the officials, the government required the contractor to average three aircraft or fewer in the depot
    per calendar year in order to meet the Air Force’s aircraft availability goal. However, they said that the average
    was about 5.5 in 2018 and 3.8 in 2019. According to officials, the decrease from fiscal year 2018 to fiscal year
    2019 was a result of decisions to delay inductions due to poor performance at the contractor depot. Program
    officials said that they conducted the additional inspections to determine whether the induction date could be
    delayed in an effort to maximize aircraft availability. However, they noted that the extra inspections can increase
    aircraft availability for a period of time, but the aircraft will still need to be inducted for depot maintenance, and
    the projected average number of aircraft in the depot for fiscal year 2020 is about 6.8 aircraft.

•   They rewrote the E-8C programmed depot maintenance plan over the past several years using Maintenance
    Steering Group-3 methodology, which follows the best practices of commercial airlines and should be better
    suited to the E-8C fleet’s aging aircraft with a long service life. To verify and validate the new methodology, in
    March 2020 the Air Force inducted into depot maintenance at Warner Robins Air Logistics Complex an E-8C
    aircraft for a major inspection. Program officials also said they plan to begin fully implementing the new
    programmed depot maintenance plan in fiscal year 2021, and that they expect the E-8C fleet’s aircraft
    availability to improve by 16 percent or more by fiscal year 2023 as the new plan is implemented across the
    fleet.

Supply Support: Program officials informed us that pylon repair has been one of the top drivers for delays in depot
maintenance. The Air Force has required more parts than originally expected for the repair of pylons—which are
used to hold the aircraft’s engines to the wings—due to the age of the pylons and workmanship issues at Northrop
Grumman’s depot maintenance facility, according to officials. Program officials said they discovered significant
process problems with pylon repair at the contractor facility and worked with the contractor to correct the issues.
Additionally, they said that they identified seven sets of unused KC-135 pylons that had undergone a major
structural improvement program and now reflect an improved design. These pylons were no longer being used by
the KC-135 program due to the KC-135 fleet’s having its engines replaced (“re-engined”), and that they were
structurally interchangeable with the E-8C pylon, according to the officials. However, the two pylon configurations
had different system components. According to program officials, the E-8C program office awarded a task on a
larger contract with Boeing in September 2019 to convert the legacy E-8C pylon to the improved KC-135
configuration with all new structural and system components. Program officials told us that they then awarded a task
on the same Boeing contract to develop the engineering and conversion data to make the KC-135 pylons useable
on E-8C aircraft. That effort is complete, and E-8C program officials said that they expect to add another contract
task under the contract with Boeing to convert the KC-135 pylons in August 2020. The E-8C program office plans for
Page 111                                                                           GAO-21-101SP Weapon System Sustainment
the KC-135 converted pylons to be installed on seven aircraft, and for 10 aircraft sets of the newly converted E-8C
pylons to be used on the remainder of the E-8C fleet. The E-8C program office projects that the first set of KC-135
pylons will be available for installation in fiscal year 2021. The KC-135 and E-8C converted pylons will be installed
on aircraft during major inspections and programmed depot maintenance, and the fleet will be completely updated in
about 3 years.

Engines: The E-8C’s TF33 engines are the leading cause of the aircraft’s being designated as not mission capable.
Maintenance and supply issues with the E-8C engines from fiscal year 2011 through fiscal year 2018 have
hampered the readiness of the aircraft, according to the program office. In 2018 Congress directed CAPE to report
on a cost, schedule, and implementation plan for restarting a dormant legacy E-8C re-engining program that the Air
Force originally initiated in 2007. 3 In January 2019 CAPE issued a report that assessed three courses of action and
concluded that continuing with the current engines provided the best cost-benefit and was most aligned with the
National Defense Strategy. 4 According to CAPE, continuing with the current engines delivers E-8C mission capable
aircraft at the lowest total cost, the lowest programmatic risk, and a similar cost per mission capable aircraft ratio as
the other potential courses of action. Since CAPE’s report was completed, the Air Force officials said that they are
designing a modification to disable the engine’s thrust reversers to address this issue without a loss of required
operational capability. They anticipate that the modification will be ready for production in early 2021. Additionally,
the officials said that they plan to begin a study to improve the reliability and maintainability of the engine by the end
of fiscal year 2020.

 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which were
incorporated where appropriate. Program officials stated that they have planned for the E-8C service life to be
capable of reaching 2045 and beyond, depending on Air Force needs. They also said that the propulsion system will
increasingly be a negative driver to mission capable rate as the fleet ages.




3See  House Report 115-874, the Conference Report accompanying a bill for the John S. McCain National Defense Authorization Act
for Fiscal Year 2019.
4Office   of the Secretary of Defense Cost Assessment and Program Evaluation E-8C JSTARS Re-engine Report to Congress, (Jan. 23,
2019).

Page 112                                                                                GAO-21-101SP Weapon System Sustainment
Page 113   GAO-21-101SP Weapon System Sustainment
                                     EA-18G Growler Sustainment Quick Look
                                     Common Name: Growler
                                     Lead Service: Navy

                                     Background

Program Essentials                   The EA-18G Growler is the fourth major variant of the F/A-18 family of
                                     aircraft and was first manufactured in 2007 to replace the EA-6B Prowler.
Manufacturer: Boeing                 The EA-18G is the first newly designed electronic warfare aircraft produced
Sustainment: Depot maintenance       in more than 35 years and combines the F/A-18 Super Hornet platform with
conducted at Navy Fleet              an advanced electronic warfare suite.
Readiness Centers and Boeing
                                     Life Cycle of the EA-18G
and field maintenance conducted
by Navy maintainers
Program Office: Program
Manager – Air 265, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 6.6 years               Overview
Average lifetime flying hours:       From fiscal years 2011 through 2019, the EA-18G fleet met or exceeded its
1,844 hours per aircraft             mission capable goals in 2 of the 9 fiscal years and its mission capable rate
                                     decreased. The fleet’s mission capable rate decreased because, according
Depot maintenance activity           to officials, EA-18Gs were being inducted into depots as part of planned
and squadron locations:              depot maintenance, shortages of maintenance personnel, and reduction in
                                     manufacturing sources to supply parts. Total operating and support (O&S)
                                     costs consistently increased, from about $336.34 million in fiscal year 2011 to
                                     about $903.96 million in fiscal year 2018, as the size of the fleet grew from 54
                                     to 138 with continued production of the aircraft during the time frame.
                                     Further, in fiscal year 2018, maintenance costs per aircraft accounted for
                                     about one-third of the total costs per aircraft.

                                     EA-18G Sustainment Status




Sustainment Challenges
and Mitigation Actions
As a newer aircraft, the EA-18G is
experiencing maintenance and
supply challenges. The Navy’s
actions to mitigate these
challenges include increasing
available space at depots for
repairs and identifying additional
vendor sources for parts.




Page 114                                                                      GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The EA-18G Acquisition Logistics Support Plan (2006)—a sustainment planning document—describes the
   Navy’s plan for design, development, and fielding of the aircraft. Some of the key support program elements
   include developing support equipment and technical data, testing requirements for avionics, and facilities
   requirements, among others. According to Navy officials, they are currently updating a life-cycle sustainment
   plan, which will include a section for each variant of the F/A-18s, but they do not have a timeline of when it will
   be finalized.

•   In November 2018, the Navy implemented the Naval Sustainment Systems approach in response to the
    Secretary of Defense’s requirement that critical aircraft, such as the EA-18G, achieve an 80-percent mission
    capable goal. The Naval Sustainment Systems approach employs industry best practices to improve aircraft
    readiness by reforming several Navy processes, such as leveraging proven commercial best practices to
    enhance fleet readiness centers, improving supply chain, and developing an engineering-driven system to
    improve aircraft sustainability. Previously in this report, we discussed the Navy’s progress in achieving this goal
    and noted that the Navy uses different data to assess its progress than the data it provided below for our
    analysis. Navy officials acknowledge that the data below provides a more comprehensive measure on the health
    of the aircraft, systems, and components. See appendix II for additional information on this issue.

•   The Navy Fleet Readiness Centers maintain the aircraft using planned maintenance intervals, which typically
    occur every 72 months. The Navy also partners with Boeing to provide wholesale supply and depot repair
    support for major components, such as the engine.

•
 Availability and Condition
The EA-18G fleet met or exceeded its annual mission capable goals in 2 of the 9 fiscal years from fiscal year 2011
through fiscal year 2019 and its mission capable rate decreased during the time period. According to officials, prior
to 2018, mission capable rates were not prioritized as the Navy was focused on other metrics, such as the ready-
basic aircraft metric. This was the minimum aircraft availability metric that indicated an aircraft was safe to fly.
However, with the renewed focus on mission capability, the Navy has implemented initiatives, such as the Naval
Sustainment Systems approach, in an effort to improve mission capable rates, as previously discussed.

From fiscal year 2011 through fiscal year 2019, the EA-18G’s rates increased for not mission capable maintenance
and not mission capable supply. Officials attributed these increases to supply chain issues, such as parts
obsolescence, increased lead times to procure parts, and diminishing manufacturing sources, which lengthened the
time that EA-18G aircraft were not mission capable. Specific details on mission capable and not mission capable
rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal years 2011 through 2018, the EA-18G’s total O&S costs increased from about $336.34 million to about
$903.96 million. Maintenance accounted for the largest share of O&S costs, averaging about $219.19 million per
year, or 32 percent of the total O&S costs over the period, and maintenance costs have also increased. According to
officials, these increases can be attributed to the increase in the inventory of the EA-18G fleet, from 54 aircraft fiscal
year 2011 to 138 aircraft in fiscal year 2018. Further, depot-level reparables was the most significant contributor to
maintenance costs, averaging about $74.27 million per year from fiscal years 2011 through 2018, or 34 percent of
the total maintenance costs during the time period. Intermediate maintenance costs accounted for the smallest
share, averaging about $14.18 million per year, or 6 percent of the total maintenance costs from fiscal years 2011
through 2018.




Page 115                                                                          GAO-21-101SP Weapon System Sustainment
EA-18G Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the EA-18G’s O&S cost per aircraft generally increased from about
$6.23 million to about $6.55 million. Also, maintenance costs per aircraft accounted for about one-third of the total
cost per aircraft, averaging about $2.06 million per year during the same time period. The number of aircraft
increased from 54 aircraft in fiscal year 2011 to 138 aircraft in fiscal year 2018, as discussed previously.




Page 116                                                                        GAO-21-101SP Weapon System Sustainment
EA-18G Operating and Support Costs per Aircraft




Sustainment Challenges and Mitigation Actions
Maintenance: The EA-18G is experiencing several maintenance challenges. For example, while the majority of the
squadrons are located at Whidbey Island, Washington, most of the component repairs are performed at Fleet
Readiness Center—West in Lemoore, California. However, according to officials, Lemoore’s depots have limited
capacity to repair these components, creating a maintenance backlog. Additionally, depot maintenance for the EA-
18G is performed at Fleet Readiness Center—Northwest in Whidbey Island, Washington; however, there is a
shortage of depot and field maintenance personnel due to attrition and an inability to find skilled workers. The
Navy’s ongoing and planned actions to mitigate these challenges include implementing the Naval Sustainment
Systems approach to leverage best practices in the maintenance industry; establishing additional maintenance
support for systems on the EA-18G, such as the electronic warfare system and the generator control unit; increasing
available space at depots to repair the aircraft; training depot and field maintainers to be proficient in repairing parts
of the aircraft outside their assigned position; and allowing depot and field maintainers to work overtime to keep up
with maintenance schedules.

Supply Support: The EA-18G is experiencing parts shortages because, according to officials, it is taking longer to
repair parts as the aircraft ages. Also, contractors are no longer producing some of these parts. The Navy’s ongoing
and planned actions to mitigate these challenges include implementing its Naval Sustainment Systems to identify
additional vendor sources, performing hardware and software upgrades, reverse engineering (the process of
examining an item, such as a spare part, with the intent of replicating its design), employing incentive strategies to
procure new parts, building additional organic repair capability and streamlining organic repair processes, adding
capability at Fleet Readiness Center—Northwest, completing system test upgrades to support component repairs,
and updating organic shop processes at Fleet Readiness Centers to improve component repair completion times.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 117                                                                          GAO-21-101SP Weapon System Sustainment
                                         F/A-18A-D Hornet Strike Fighter Sustainment
                                         Quick Look
                                         Common Name: Legacy Hornet
                                         Lead Service: Navy and Marine Corps

Program Essentials                       Background
Manufacturer: McDonnell                  The F/A-18A-D Hornet Strike Fighter is a twin engine, multimission tactical
Douglas and Boeing                       aircraft initially fielded in the 1980s. In its fighter mode, it is used primarily as
                                         a fighter escort and air defense; in its attack mode, it is used for interdiction
Sustainment: Depot maintenance           and air support.
conducted at Navy Fleet
Readiness Centers and Boeing             Life Cycle of the F/A-18A-D
and field maintenance conducted
by Navy maintainers
Program Office: Program
Manager – Air 265, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 27.6 years                  Overview
Average lifetime flying hours:           From fiscal years 2011 through 2019, the Navy’s F/A-18A-D fleet met or
7,585 hours per aircraft                 exceeded its annual mission capable goals in one of the 9 fiscal years and
                                         the Marine Corps’ F/A-18A-D fleet fell short of its goals every year. The
Depot maintenance activity
and squadron locations:                  mission capable rates for both the Navy’s and the Marine Corps’ F/A-18A-D
                                         fleets decreased during the time period. Total operating and support (O&S)
                                         costs for the fleet decreased consistently from about $3.09 billion in fiscal
                                         year 2011 to about $1.98 billion in fiscal year 2018, partly due to the F/A-
                                         18A-D being transitioned out of service to be replaced by the F-35 Joint
                                         Strike Fighter. In fiscal year 2018, the O&S costs per aircraft were $4.5
                                         million, with about $2 million per aircraft dedicated to maintenance issues.

                                         F/A-18A-D Sustainment Status




Sustainment Challenges
and Mitigation Actions
The F/A-18A-D is an aircraft
operating beyond its planned
service life with maintenance and
supply challenges. The Navy’s
actions to mitigate these
challenges include extending the
service life of the aircraft, allowing
maintainers to work overtime to
reduce backlog, and streamlining
repair processes.
Page 118                                                                             GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The In-Service Support Plan (2001) documents the engineering, logistics, and financial resources necessary to
   ensure continued readiness and supportability for the remainder of the aircraft’s service life. According to Navy
   officials, they are currently updating a life-cycle sustainment plan that will include a section for each variant of
   the F/A-18s, and they do not have a timeline of when it will be finalized.

•   In November 2018, the Navy implemented the Naval Sustainment Systems approach in response to the
    Secretary of Defense’s requirement that critical aircraft, such as the F/A-18A-D, achieve an 80 percent mission
    capable rate. The Naval Sustainment Systems approach plans to leverage proven commercial best practices to
    enhance fleet readiness centers, improve the supply chain, and develop an engineering-driven system to
    improve aircraft sustainability. Previously in this report, we discussed the Navy’s progress in achieving this goal.
    Additionally, we noted that the Navy uses different data to assess its progress in achieving this goal than the
    data it provided below for our analysis. Navy officials acknowledge that the data below provides a more
    comprehensive measure on the health of the aircraft, systems, and components. See appendix II for additional
    information on this issue.

•   The Navy implemented the High-Flight-Hour program in 2006 to extend the service life from 8,000 to 10,000
    flight hours by inspecting and repairing airframes, and replacing major components and parts.

•   The Navy Fleet Readiness Centers maintain the aircraft using planned maintenance intervals, which typically
    occur every 48 months for carrier deploying aircraft, and every 72 months for land-based aircraft.


 Availability and Condition
From fiscal year 2011 through fiscal year 2019, the Navy’s F/A-18A-D fleet met or exceeded its annual mission
capable goals in one of the 9 fiscal years and its mission capable rate decreased during the time period. According
to officials, the decrease in the mission capable rate occurred, partly, as a result of sequestration in 2013, which
limited funding to support scheduled depot maintenance, resulting in less aircraft available for training and missions.
In addition, the aircraft is aging requiring additional repairs and the inventory of the F/A-18A-D is decreasing as the
aircraft is approaching its end of service.

From fiscal year 2011 through fiscal year 2019, the Marine Corps’ F/A-18A-D fleet fell short of its annual mission
capable goals each year, and its mission capable rate decreased over the same time period. According to officials,
the Marine Corps’ F/A-18A-D fleet missed its goals partly because of the increased inspections and repairs
associated with the service-life extension of the aircraft.

The Navy’s F/A-18A-D not mission capable maintenance (NMCM) rates in fiscal years 2011 and 2019 were about
the same and it’s not mission capable supply (NCMS) rate increased when comparing those two years. According to
officials, the NMCS increase was a result of a greater demand for parts for repairs associated with service-life
extension activities and maintenance issues that were not anticipated for a fleet with an original service life of 6,000
flight hours.

The Marine Corps’ F/A-18A-D NMCM rate increased from fiscal year 2011 thorugh fiscal year 2019 and its NMCS
rate increased slightly. According to officials, the overall increase in the not mission capable rates was a result of
increased inspections and repairs associated with extending the service life of the aircraft. Specific details on
mission capable and not mission capable rates were omitted because the information was deemed by DOD to be
sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the Navy’s and Marine Corps’ F/A-18A-D’s total O&S costs
decreased from about $3.09 billion to about $1.98 billion. Maintenance costs accounted for the largest share of O&S
costs, averaging about $1.15 billion per year, or 44 percent of total O&S cost over the period, but total annual O&S
costs have decreased. According to officials, this was a result of the decrease in the total fleet aircraft of the F/A-
18A-D across the Navy and Marine Corps, from 581 aircraft in fiscal year 2011 to 440 aircraft in fiscal year 2018 as
aircraft were transitioned out of service. Also, the cost of depot-level reparables was the most significant contributor
to maintenance costs, averaging about $487.18 million a year, or 42 percent of the total maintenance costs from
fiscal years 2011 through 2018.


Page 119                                                                          GAO-21-101SP Weapon System Sustainment
F/A-18A-D Total Operating and Support Costs




From fiscal years 2011 through 2018, the O&S costs per F/A-18A-D aircraft generally decreased from about $5.32
million to about $4.50 million. This was a result of the decrease in total fleet aircraft, as previously discussed, along
with a corresponding reduction in unit operations and unit-level manpower. Also, maintenance costs per aircraft
were about 40 percent of total O&S costs per aircraft across the time frame.




Page 120                                                                           GAO-21-101SP Weapon System Sustainment
F/A-18A-D Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: The Navy and Marine Corps have extended the F/A-18A-D’s service life by 4,000 flight hours beyond its
planned service life of 6,000 flight hours. As the fleet ages, some F/A-18A-D have been permanently removed from
service, decreasing the number of aircraft available for missions. The Navy’s and Marine Corp’s ongoing and
planned actions to mitigate these challenges include extending the service life of the F/A-18A-D to 10,000 flight
hours through its High Flight Hour program—such as replacing major components including the landing gear—to
increase the service life of the aircraft, and moving aircraft between squadrons to meet the requirements of
deploying missions.

Maintenance: As the Navy’s and Marine Corps’ F/A-18A-D age beyond their designed service lives, they require
additional maintenance for repairs that were not originally planned, such as repairs for corrosion, which have
created engineering challenges and maintenance activities that take longer to perform. Also, shortages of depot and
field maintenance personnel because of attrition and the inability to find skilled workers have caused maintenance
backlogs. The Navy’s and Marine Corps’ ongoing and planned actions to accelerate maintenance improvements
include implementing the Naval Sustainment System that leverages best practices in the maintenance industry,
according to Navy officials; training depot and field maintainers to be proficient in repairing parts of the aircraft
outside their assigned position; allowing depot and field maintainers to work overtime to keep up with maintenance
schedules; and mitigating the effects of personnel shortages, where feasible, by augmenting with contractor
personnel to perform maintenance activities.

Supply Support: The Navy’s and Marine Corps’ F/A-18A-D are experiencing shortages of parts due to
obsolescence and reduced vendor base and depot capacity. The Navy’s ongoing and planned actions through the
Naval Sustainment System include identifying alternate vendors for parts, performing hardware and software
upgrades that improve reliability and maintainability, reverse engineering parts in order to be able to improve supply
availability, streamlining repair processes for parts, leveraging their foreign partner’s depot capability while standing
up additional repair capabilities for parts, implementing new contracting incentive strategies––such as long term
performance based sustainment contracts––and partnering with original equipment manufacturers for supply
support.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.
Page 121                                                                          GAO-21-101SP Weapon System Sustainment
                                       F/A-18E/F Super Hornet Sustainment Quick Look
                                       Common Name: Super Hornet
                                       Lead Service: Navy

                                       Background
Program Essentials                     The F/A-18E/F Super Hornet was first manufactured in 1997. The F/A-18E/F
                                       is a twin-engine strike fighter, an air-to-ground attack aircraft, as well as an
Manufacturer: Boeing
                                       air-to-air fighter. Its missions include escort and fleet air defense, force
Sustainment: Depot maintenance         projection, interdiction, and close air support, among others.
conducted at Navy Fleet
Readiness Centers and field            Life Cycle of the F/A-18E/F
maintenance conducted by Navy
maintainers
Program Office: Program
Manager – Air 265, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
                                       Overview
Average age: 12.1 years
                                       From fiscal years 2011 through 2019, the F/A-18E/F fleet did not meet any of
Average lifetime flying hours:         its annual mission capable goals and its mission capable rate decreased.
3,526 hours per aircraft               Total operating and support (O&S) costs steadily increased from about $2.16
                                       billion in fiscal year 2011 to about $3.29 billion in fiscal year 2018. In fiscal
Depot maintenance activity             year 2018, maintenance costs were $1.45 billion, or 44 percent, of total O&S
and squadron locations:                costs and the largest contributors were depot-level reparables ($551.02
                                       million) and depot maintenance ($303.25 million). From fiscal years 2011
                                       through 2018, the O&S cost per aircraft for the F/A-18E/F increased by over
                                       three-quarters of a million dollars, while the mission capable rate steadily
                                       declined to below 50 percent.

                                       F/A-18E/F Sustainment Status




Sustainment Challenges
and Mitigation Actions
The F/A-18E/F is a frequently-
used aircraft with maintenance
and supply challenges. The
Navy’s actions to mitigate these
challenges include implementing
the Naval Sustainment System
and plans to extend the service life
of the aircraft.




Page 122                                                                         GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The Navy is extending the service life of the F/A-18E/F aircraft through a Service Life Management Program.
   Based upon the Navy's assessment of the number of flight hours the aircraft can safely continue to fly, the Navy
   has a contract with Boeing to extend the service life of the Super Hornet from 6,000 to 10,000 hours through
   modifications.

•   The F/A-18E/F aircraft are maintained at Navy Fleet Readiness Centers under planned maintenance intervals
    that occur about every 72 months.

•   In November 2018, the Navy implemented the Naval Sustainment Systems approach in response to the
    Secretary of Defense’s requirement that critical aircraft, such as the F/A-18E/F, achieve an 80-percent mission
    capable goal. According to the Navy, the Naval Sustainment System approach plans to leverage proven
    commercial best practices to enhance fleet readiness centers, improve the supply chain, and develop an
    engineering-driven system to improve aircraft sustainability, among other things. Previously in this report, we
    discussed the Navy’s progress in achieving this goal. Additionally, we noted that the Navy uses different data to
    assess its progress in achieving this goal than the data it provided below for our analysis. Navy officials
    acknowledge that the data below provides a more comprehensive measure on the health of the aircraft,
    systems, and components. See appendix II for additional information on this issue.


 Availability and Condition
From fiscal year 2011 through fiscal year 2019, the F/A-18E/F fleet missed all of its annual mission capable goals
and its mission capable rate decreased during the time period.

From fiscal years 2011 through 2019, the F/A-18E/F’s rates increased for not mission capable maintenance
(NMCM) and not mission capable supply (NMCS). The NMCM rate was higher in the interim years, but by fiscal
year 2019 the NMCM rate was about the same as it was in fiscal year 2011.. According to Navy officials, the
increases in the not mission capable rates during this time were the result of budget sequestration and associated
funding shortages. In addition, the increase in aircraft inventory, along with aging airframes, imposed additional
requirements on the maintenance community and negatively affected the NMCM rate. Further, officials cited
excessive supplier lead times, diminishing manufacturing sources, and material requirements that were not originally
forecasted for the initial 6,000-hour service-life expectancy as other reasons for the NMCS rate increase. Specific
details on mission capable and not mission capable rates were omitted because the information was deemed by
DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the F/A-18E/F’s total O&S costs increased about $1.13 billion, from
$2.16 billion to $3.29 billion, as mission capable rates decreased. Costs for maintenance and continuing systems
improvements increased the most over the period, about $700.15 million and $263.73 million, respectively. Navy
officials stated that maintenance costs increased due to sustained high flight hours, which increased the probability
of parts failure on the aircraft, and an increasing aircraft inventory, as the F/A-18E/F is still in production.
Maintenance costs also increased as the Navy has worked to address extensive maintenance needs associated
with extending the service life of the aircraft from 6,000 hours to 10,000 hours, according to Navy officials. For
example, several life-limited components, such as particular surfaces on the aircraft, require replacement at 6,000
flight hours, and this has increased the depot-level reparable costs in the fiscal year 2016-2018 time frames.
Officials said that the continuing system-improvement cost increases in fiscal years 2016 through 2018 were due to
a number of modification efforts, such as improvements to the avionics for the aircraft and modifications associated
with the service-life extension.




Page 123                                                                        GAO-21-101SP Weapon System Sustainment
F/A-18E/F Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the O&S costs per aircraft for the F/A-18E/F increased from about
$5.58 million to about $6.41 million, while the mission capable rate steadily declined to below 50 percent. Also,
maintenance costs per aircraft increased from about $1.92 million (34 percent of the total O&S costs per aircraft) in
fiscal year 2011 to $2.82 million per aircraft (44 percent of the total O&S costs per aircraft) in fiscal year 2018. The
number of F/A-18E/F aircraft increased from 388 to 513 during the same time frame.




Page 124                                                                          GAO-21-101SP Weapon System Sustainment
F/A-18E/F Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: Since the Navy frequently used the F/A-18E/F over the past decade to support contingency operations, the
aircraft has required additional maintenance and, according to Navy officials, the aircraft requires a life extension to
remain a viable weapon system. According to officials, the Navy is extending the F/A18E/F’s service life from 6,000
flight hours to 10,000 flight hours, as previously discussed. The Navy plans to implement lessons learned from other
service-life extension programs (e.g., F/A-18A-D Hornet Strike Fighter), such as monitoring depot induction flows
and obtaining contractor support from Boeing to assist with initial program challenges, including knowledge, skills,
and facilities.

Maintenance: According to officials, the number of F/A-18E/F aircraft that are not mission capable for maintenance
is a significant challenge, as are historically-inconsistent funding levels in sustainment accounts. Officials said that
the Navy developed a plan for the F/A-18E/F to improve readiness, and that the enhancements being driven through
the establishment of the Navy Sustainment Systems in November 2018, discussed previously, are the actions being
taken to increase the aircraft’s mission capable rate. Additionally, to promote more stable sustainment funding, Navy
officials are preparing a 2-year program sustainment budget and an additional, 3-year sustainment funding plan to
inform leadership of the long-term requirements of the program. This plan will be updated annually to align with each
budget cycle.

Supply Support: Even though the F/A-18E/F is still in production, the aircraft is experiencing shortages of parts that
suppliers are no longer producing. Also, according to officials, suppliers are slow in providing parts, which increases
maintenance wait times. Ongoing and planned actions include locating other vendor sources, reverse engineering,
and cannibalizing parts (i.e., removing serviceable parts from one aircraft and installing them in another aircraft).
Additionally, the Naval Sustainment System, discussed earlier, includes an Integrated Supply Chain Management
Team to improve supply support, according to Navy officials.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.



Page 125                                                                         GAO-21-101SP Weapon System Sustainment
                                    F-35 Lightning II Joint Strike Fighter Sustainment
                                    Quick Look
                                    Common Name: F-35
                                    Lead Service: Joint

Program Essentials                  Background
Manufacturer: Lockheed Martin       The F-35 Lightning II is a strike fighter aircraft that integrates low-observable
                                    (stealth) technology with advanced sensors and computer networking
Sustainment: Depot maintenance      capabilities for the U.S. Air Force, Marine Corps, and Navy. Each service has
conducted by Lockheed Martin        its own variant of the aircraft with service-specific capabilities. The Air Force
and field maintenance conducted     utilizes the F-35A, the Marine Corps utilizes the F-35B and the F-35C, and
by service personnel.               the Navy utilizes the F-35C. Production on the F-35 is expected to continue
Program Office: Joint Program       through fiscal year 2044. In this report, we focus on the United States’ F-35
Office, Arlington, Virginia         fleet.

 Fiscal Year 2019 Data              Life Cycle of the F-35 Lightning II
Average age: F-35A: 3.1 years;
F-35B: 4.0 years; F-35C: 3.9
years.
Average lifetime flying hours: F-
35A: 561 hours; F-35B: 616 hours;
F-35C: 677 hours.
Depot maintenance activity
and squadron locations:             Overview
                                    The F-35 variants met few of their threshold performance targets for air
                                    vehicle availability and mission capable rates from fiscal years 2012 through
                                    2019, and none of the variants met their objective threshold targets for either
                                    of the rates. However, the aircraft availability and mission capable rates for
                                    all of the F-35 variants increased during the time period. Total operating and
                                    support (O&S) costs for all three variants have increased over time as more
                                    airplanes are produced. From fiscal year 2011 to fiscal year 2018, total O&S
                                    costs for the F-35 program increased from $55.60 million to $2,183.63
                                    million, with $758.35 million, or about 35 percent, spent on maintenance. The
                                    majority of the costs were from the F-35A, which has the most aircraft
                                    inventory.

                                    F-35 Sustainment Status


Sustainment Challenges
and Mitigation Actions
The F-35 faces significant
challenges related to its supply
chain and the program office is
taking steps to address these
challenges.




Page 126                                                                      GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The F-35’s Life-Cycle Sustainment Plan was issued in January 2019 and describes performance imperatives,
   metrics, and eight success elements. According to the plan, these success elements are the first steps towards
   achieving an 80 percent mission capable rate for combat aircraft. The plan also defines actions to reduce
   operating and maintenance costs each year.

•   Sustainment of the F-35 is a large and complex undertaking with several key stakeholders. The F-35 Joint
    Program Office, through its Product Support Manager, is responsible for managing and overseeing the support
    functions required to field and maintain the readiness and operational capability of the F-35 aircraft across the
    enterprise. As such, it establishes sustainment requirements, manages funding, develops contracts, and
    provides direction for and oversees the execution of F-35 sustainment strategy and policy.

•   The F-35 program relies heavily on contractors to provide support for its F-35 aircraft. DOD has two primary
    contractors for the F-35 program: Lockheed Martin for the overall aircraft system and Pratt & Whitney for the
    engine. As the prime contractor for the overall aircraft system, Lockheed Martin is responsible for managing the
    F-35 supply chain, depot maintenance, and pilot and maintainer training, as well as for providing engineering
    and technical support.

•   The F-35 program is a joint, multinational acquisition program with a global supply chain intended to be a
    network of manufacturers, commercial and government part repair depots, and base and regional part
    warehouses that will be located around the world to provide parts to support the operational and training
    requirements of all F-35 program participants. All F-35 program participants share a global pool of F-35 spare
    parts.


 Availability and Condition
From fiscal years 2012 through 2019, the F-35A fleet did not meet its annual threshold performance targets for air
vehicle availability, but met the threshold performance targets for the mission capable rate in 2 of the 8 fiscal years.
The F-35A fleet did not meet any of its annual objective performance targets—for either the air vehicle availability
rate or the mission capable rate. However, the F-35A’s availability and mission capable rates both increased over
the eight-year period.

The F-35B fleet did not meet its annual threshold performance targets for air vehicle availability, but met these
targets for its mission capable rate in 1 of the 7 years from fiscal years 2013 through 2019. The F-35B fleet did not
meet any of its annual objective performance targets—for either the aircraft availability rate or the mission capable
rate. However, both the F-35B’s aircraft availability rate and mission capable rate increased over the seven-year
period.

From fiscal years 2013 through 2019, the F-35C fleet met its annual threshold performance targets for air vehicle
availability in 2 of the 7 years and met the threshold performance targets for the mission capable rate in 2 of the 7
fiscal years. The F-35C fleet did not meet any of its annual objective performance targets—for either the aircraft
availability rate or the mission capable rate. However, both the F-35C’s aircraft availability rate and its mission
capable rate increased over the eight-year period.

Although the rates varied somewhat during the time period, in general, from fiscal years 2012 through 2019 the not
mission capable maintenance rates for all of the F-35 variants decreased and the not mission capable supply rates
increased. Spare parts shortages throughout the F-35 supply chain are contributing to F-35 aircraft being unable to
perform as many missions or to fly as often as the warfighter requires. As we have previously reported, lower than
required F-35 aircraft performance is attributable in part to spare parts shortages. Specifically, the F-35 supply chain
does not have enough spare parts available to keep aircraft flying enough of the time necessary to meet warfighter
requirements.1 Several factors contributed to these parts shortages, including F-35 parts breaking more often than
expected, and DOD’s limited capability to repair parts when they break. Specific details on mission capable and not
mission capable rates were omitted because the information was deemed by DOD to be sensitive.



1See  GAO, F-35 Aircraft Sustainment: DOD Needs to Address Substantial Supply Chain Challenges, GAO-19-321 (Washington, D.C.:
Apr. 25, 2019).

Page 127                                                                             GAO-21-101SP Weapon System Sustainment
 Operating and Support Costs
The F-35 is DOD’s most costly weapon system, with sustainment costs estimated at more than $1 trillion over a 60-
year life cycle. Total O&S costs have grown from $55.6 million in fiscal year 2011 to $2.18 billion in fiscal year 2018,
with the F-35A accounting for the majority of those costs. Maintenance costs have increased from $15.76 million to
$758.35 million during this same timeframe, again with the the F-35A accounting for the majority of these costs. In
2018, DOD established affordability constraints based on the military services’ furture budget projections. These
new affordabiltiy constraints will require DOD to reduce F-35 sustainment costs per aircraft per year by 43 percent
for the Air Force, 24 percent for the Marine Corps, and 5 percent for the Navy. Total O&S costs for the F-35A have
risen from $55.60 million in fiscal year 2011 to $1.18 billion in fiscal year 2018. Maintenance costs for the F-35A also
increased during this time period, from $15.76 million in fiscal year 2011 to $553.71 million in fiscal year 2018, and
the percentage of the total O&S costs spent on maintenance increased from 28 percent to 47 percent.


F-35A Total Operating and Support Costs




Total O&S costs for the F-35B increased from $77.13 million in fiscal year 2012 to $651.13 million in fiscal year
2018, while total maintenance costs increased from $76.74 million to $137.18 million during this same time frame.
Maintenance costs were steady from fiscal year 2012 through fiscal year 2015, then began to increase in fiscal year
2016. In fiscal year 2018, maintenance costs accounted for 21 percent of the total O&S costs for the F-35B.




Page 128                                                                         GAO-21-101SP Weapon System Sustainment
F-35B Total Operating and Support Costs




For the F-35C, total O&S costs have increased from $14.68 million in fiscal year 2013 to $348.10 million in fiscal
year 2018. During this same time period, maintenance costs increased from $6.55 million to $67.46 million, though
the percentage of total costs spent on maintenance decreased from 45 percent in fiscal year 2013 to 19 percent in
fiscal year 2018.




Page 129                                                                      GAO-21-101SP Weapon System Sustainment
F-35C Total Operating and Support Costs




As the size of the fleet has grown, the total O&S cost per aircraft for the F-35 has decreased. Per aircraft total O&S
costs for the F-35 fleet have decreased from $27.8 million in fiscal year 2011 to $9.93 million in fiscal year 2018. For
the F-35A, total O&S costs per aircraft have decreased from $27.8 million in fiscal year 2011 to $8.84 million in fiscal
year 2018. During this time period, the size of the F-35A fleet has increased from two to 134.




Page 130                                                                         GAO-21-101SP Weapon System Sustainment
F-35A Operating and Support Costs per Aircraft and Fleet Size




Per aircraft total O&S costs for the F-35B have increased from $7.71 million in fiscal year 2012 to $11.23 million in
fiscal year 2018. During this same time period, the percentage of costs attributed to maintenance has changed from
almost 100 percent in fiscal year 2012 to 21 percent in fiscal year 2018.



F-35B Operating and Support Costs per Aircraft and Fleet Size




For the F-35C, per aircraft total O&S costs have increased from $7.34 million in fiscal year 2013, to $12.43 million in
fiscal year 2018 while the number of aircraft have increased from two to 28 during this same time period.

Page 131                                                                         GAO-21-101SP Weapon System Sustainment
F-35C Operating and Support Costs per Aircraft and Fleet Size




Challenges and Mitigation Actions
Supply: As we have previously reported, the F-35 has experienced spare parts shortages. In 2018, DOD had a
repair backlog of about 4,300 F-35 parts. DOD is taking steps to address these issues such as improving timing of
spare parts deliveries. In addition, DOD purchased certain parts in advance, but as the F-35 has been modified over
time, these parts can no longer be used on the aircraft. For example, 44 percent of purchased parts were
incompatible with aircraft the Marine Corps took on a recent deployment. Finally, DOD’s networks for moving F-35
parts around the world are immature, and F-35 customers overseas have experienced long wait times for parts
needed to repair aircraft. In addressing these challenges, DOD must grapple with affordability. The Air Force and
Marine Corps recently identified the need to reduce their sustainment costs per aircraft per year by 43 and 24
percent, respectively. DOD has spent billions of dollars on F-35 spare parts but does not have records for all the
parts it has purchased, where they are, or how much they cost. We have made recommendations to DOD to
improve these issues. DOD concurred and has identified several actions it is planning to take, including developing
a process to modify spare parts packages to better match deploying aircraft, revising business rules to better
prioritize scarce parts, and working with the contractor to provide better supply-related data.

Maintenance: In addition to parts shortages, DOD has limited capability to repair parts when they break.
Specifically, as of April 2019, the F-35 program was failing to meet four of its eight reliability and maintainability
targets—which determine the likelihood that the aircraft will be in maintenance rather than available for operations—
including metrics related to part removals and part failures. For example, we previously reported that the special
coating on the F-35 canopy that enables the aircraft to maintain its stealth had failed more frequently than expected,
and that the manufacturer was unable to produce enough canopies to meet demands. These reliability challenges
are exacerbated by DOD’s limited capability to repair broken parts at the military depots. The capabilities to repair
parts are currently 8 years behind schedule. DOD originally planned to have repair capabilities at the depots ready
by 2016, but the depots will not have the capability to repair all parts at expected demand rates until 2024. As a
result, the average time taken to repair an F-35 part was more than 6 months, or about 188 days, for repairs
completed between September and November 2018—more than twice as long as planned. According to the Joint
Program Office, it has taken several steps to accelerate depot repair, including reducing the time it takes to activate
a depot, aligning procurement and delivery of repair parts so that parts are available earlier, and initiating
performance-based logistics contracts with original equipment manufacturers to incentivize performance and cost
improvements.


Page 132                                                                         GAO-21-101SP Weapon System Sustainment
Program Office Comments
The Joint Program Office provided technical comments, which we incorporated where appropriate.




Page 133                                                                   GAO-21-101SP Weapon System Sustainment
                                   AV-8B Harrier Sustainment Quick Look
                                   Common Name: AV-8B
                                   Lead Service: Marine Corps

                                   Background
Program Essentials                 The AV-8B Harrier is a vertical/short take-off and landing attack aircraft first
                                   manufactured in 1984. The AV-8B conducts close air support, intermediate
Manufacturers: McDonnell
                                   range intercept, and attack missions. The AV-8B can deploy from aircraft
Douglas, British Aerospace,
                                   carriers and other suitable seagoing platforms, as well as forward operating
Boeing, BAE Systems
                                   bases, expeditionary airfields, and remote landing sites.
Sustainment: Depot maintenance
conducted at Navy Fleet            Life Cycle of the AV-8B
Readiness Centers and field
maintenance conducted by Marine
Corps maintainers
Program Office: Program
Manager-Air 257, Naval Air
Systems Command, Patuxent
River, Maryland
                                   Overview
Fiscal Year 2019 Data
Average age: 24.1 years            The AV-8B fleet did not meet any of its annual mission capable goals from
                                   fiscal years 2011 through 2019 and its mission capable rate decreased
Average lifetime flying hours:     during the time period. According to program officials, this decrease was
5,169 hours                        partly because of challenges in operations and maintenance planning due to
                                   wartime surges and an uncertain deployment schedule. Total operating and
Depot maintenance activity         support (O&S) costs have generally decreased, from $832.66 million in fiscal
and squadron locations:            year 2011, to $567.19 million in fiscal year 2018. All of the O&S cost
                                   categories decreased except sustaining support, partly because the inventory
                                   is decreasing as the Marine Corps transitions AV-8B squadrons to the F-35B
                                   Lightening II Joint Strike Fighter. In fiscal year 2018, about half of the total
                                   $5.91 million O&S costs per aircraft was for aircraft maintenance.

                                   AV-8B Sustainment Status




Sustainment Challenges
and Mitigation Actions
The AV-8B faces maintenance
personnel and supply challenges.
Actions to mitigate these
challenges include upgrading
components and developing other
vendors for parts.




Page 134                                                                     GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The AV-8B was originally expected to remain in service through 2015, according to the AV-8B Logistics
   Program Plan (2016). However, the Marine Corps currently plans to keep the AV-8B in service through 2028.
   Changes in the length of service life have been partly the result of F-35B Joint Strike Fighter production delays,
   as sufficient numbers of the F-35Bs that are needed to replace the AV-8B fleet will not be available until years
   later than originally planned.

•   The AV-8B is maintained at Navy Fleet Readiness Centers under planned maintenance intervals occurring at
    least every 1,500 flight hours. Supply support is provided by Naval Supply Systems Command and Defense
    Logistics Agency; contractor support services are provided by Boeing and BAE Systems.


 Availability and Condition
From fiscal year 2011 through fiscal year 2019, the AV-8B fleet missed all of its annual mission capable goals and
its mission capable rate decreased during the time period.

The AV-8B fleet’s rates increased for not mission capable maintenance (NMCM) and not mission capable supply
(NMCS) from fiscal years 2011 through 2019, but the NMCS rate was only slightly higher at the end of the period. A
Marine Corps Independent Readiness Review commissioned in fiscal year 2014 concluded that AV-8B maintenance
personnel levels were unable to support the demands for labor, among other things. An AV-8B program official
confirmed that there were still too few maintainers across the AV-8B fleet in fiscal year 2018 and also stated that
there were more squadrons and aircraft currently in the inventory than expected. The official explained that,
although two AV-8B squadrons had transitioned to F-35B squadrons, the number of AV-8B aircraft was not reduced.
Also, several new systems and upgrades were added to the aircraft that further exacerbated the maintenance
personnel issue, according to the program official. Program officials noted that increases in not mission capable
rates were also partly because the program faced challenges in operations and maintenance planning due to
combat surges from Operations Iraqi Freedom and Enduring Freedom and delays in the transition of the AV-8B
squadrons’ Pacific deployments to F-35 squadrons. Specific details on mission capable and not mission capable
rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
The AV-8B fleet’s total O&S costs decreased about $265 million—or 32 percent—from $832.66 million in fiscal year
2011, to $567.19 million in fiscal year 2018. Maintenance costs accounted for the largest share of the program’s
O&S costs, averaging about 51 percent of total costs from fiscal year 2011 through fiscal year 2018. Maintenance
costs decreased during the 8-year time period, along with all of the other O&S cost categories except sustaining
support. According to a program official, O&S costs decreased for several reasons. First, the Marine Corps operated
23 fewer AV-8Bs in 2018 than in 2011, partly due to the loss of six aircraft following the 2012 Camp Bastion attack
in Afghanistan and the transition of two AV-8B squadrons to the F-35 Joint Strike Fighter. Second, the Marine Corps
flew the AV-8B less following Operation Iraqi Freedom and Operation Enduring Freedom. Finally, total O&S costs
decreased because of the use of the parts inventory from the GR-9 fleet, the United Kingdom’s AV-8B equivalent,
after it was purchased in 2011. Program officials stated that maintenance costs were higher in fiscal years 2012 and
2013 due to the reconstitution of aircraft from Operation Enduring Freedom and because of the parts that were
replaced and repaired following the attack on Camp Bastion. The cost of depot-level reparables was the most
significant contributor to maintenance costs, averaging about $129.16 million a year, or 35 percent of the total
maintenance costs from fiscal year 2011 through fiscal year 2018. A program official noted that over 60 percent of
AV-8B parts are repaired at Navy Fleet Readiness Centers. The other maintenance cost category accounted for the
smallest share of maintenance costs, averaging about $9.18 million a year, or 2 percent of total maintenance costs
during the same time period.




Page 135                                                                        GAO-21-101SP Weapon System Sustainment
AV-8B Total Operating and Support Costs




The number of AV-8B aircraft declined from 119 to 96 aircraft from fiscal year 2011 through fiscal year 2018. The
total O&S costs per aircraft went down from about $8.02 million in fiscal year 2012, to about $5.91 million in fiscal
year 2018. With the exception of fiscal years 2012, 2013, and 2017, the maintenance costs per aircraft has
remained fairly steady, averaging about $3.40 million per aircraft.




Page 136                                                                         GAO-21-101SP Weapon System Sustainment
AV-8B Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: Many AV-8B aircraft are operating beyond the planned service life of 6,000 flight hours, but program officials
stated that assessments by the Marine Corps have determined that the aircraft are still able to operate. According to
officials, the Marine Corps has several ongoing and planned actions to keep the AV-8B in service until it is replaced
by the F-35B Joint Strike Fighter, including upgrading engine components and reassessing the life expenditure
model based on actual flight profiles to make sure the aircraft can continue to meet Marine Corps mission needs.

Maintenance: The AV-8B required additional maintenance for unplanned repairs due to the system’s aging
airframe, maintenance activities taking longer to perform, and the AV-8B’s vulnerability to foreign-object damage
due to the aircraft’s design and its operating locations. Also, according to Marine Corps officials, there is a shortage
of AV-8B-specific maintenance personnel because of the previous expected transition to the F-35. These officials
stated that the Marine Corps’ ongoing and planned actions include identifying all parts and components that need to
be repaired and replaced during the inspection phase, keeping up with maintenance schedules, conducting
analyses on major components and upgrading as needed, and increasing awareness of maintainers and other
personnel to mitigate foreign-object damage. Program officials also noted that depot, contractor, and field
maintainers are coordinating efforts at Fleet Readiness Centers to reduce the time needed for disassembly and
reassembly processes to reduce maintenance backlogs.

Supply Support: The AV-8B experienced shortages of parts that suppliers are no longer producing. The Marine
Corps’ ongoing and planned actions, according to officials, include developing additional vendor sources, hardware
and software upgrades, the removal of parts from damaged aircraft for use on operating aircraft once the parts have
been inspected and approved for use, and continuing engineering analysis to identify items that can be used from
the purchase of the United Kingdom’s GR-9 equivalent of the AV-8B.

 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which were
incorporated where appropriate. Also, officials noted the following: In fiscal year 2019, six AV-8B aircraft were
placed in preservation on the flight line and four aircraft were recommended for the Stricken Aircraft Reclamation
and Disposal Program, reducing the number of in-reporting aircraft from 16 to 14 per squadron. Also, while the
material procured from the United Kingdom’s GR-9 fleet has had a measurable effect on AV-8B supply support and
the NMCS rate over the period addressed in this report, it is not expected that the availability of material remaining
Page 137                                                                         GAO-21-101SP Weapon System Sustainment
will guarantee similar results for the next 9 years until the planned sunset year. Therefore, the continued
identification and development of vendors and repair sources in the continental United States and the United
Kingdom are critical, as well as a comprehensive contractor logistic support strategy to enhance the ability of the
AV-8B to maintain relevance, meet deployment requirements, and successfully achieve the out-of-service date.




Page 138                                                                        GAO-21-101SP Weapon System Sustainment
                                      A-10 Thunderbolt II Sustainment Quick Look
                                      Common Name: A-10
                                      Lead Service: Air Force

                                      Background
Program Essentials                    The A-10 Thunderbolt II was first manufactured in 1975 and is expected to
                                      remain in service through at least 2030. The A-10 is a single-seat aircraft
Manufacturer: Fairchild Republic
                                      specifically designed for close air support and defeating enemy armor. The
Company
                                      A-10 is maneuverable at low speeds and altitude and can carry a variety of
Sustainment: Depot maintenance        conventional munitions. The aircraft’s wide combat radius and short takeoff
conducted by the Air Force at         and landing capability permit operations near the front lines.
Ogden Air Logistics Complex,
Utah, and by a contractor             Life Cycle of the A-10
overseas; field maintenance
performed by Air Force
maintainers
Program Office: Hill Air Force
Base, Utah
Fiscal Year 2019 Data
Average age: 39 years                 Overview
Average lifetime flying hours:        From fiscal years 2011 through 2019, the A-10 fleet met its aircraft availability
11,625 hours per aircraft             and mission capability goals in one of the 9 years. The A-10’s aircraft
                                      availability rate increased slightly and its mission capability rate was less than
Depot maintenance activity            one percentage point higher in fiscal year 2019 than it was in fiscal year
and squadron locations:               2011. Total operating and support costs (O&S) for the A-10 fleet decreased
                                      from about $2.22 billion in fiscal year 2011 to about $1.63 billion in fiscal year
                                      2018—a decrease of about $588 million over this period. According to Air
                                      Force officials, this decrease was largely due to the retirement of 61 high-
                                      hour aircraft, resourcing decisions made as a result of the Air Force’s
                                      proposed—but not congressionally approved—divestiture of the entire A-10
                                      fleet, and the temporary removal of 18 aircraft from service that was also due
                                      to resourcing decisions. Further, total O&S costs per aircraft decreased from
                                      $6.41 million in fiscal year 2011 to $5.78 million in fiscal year 2018.

                                      A-10 Sustainment Status




Sustainment Challenges
and Mitigation Actions
The A-10 faces aging and
maintenance challenges.
Mitigation actions include
purchase of new wings, a Central
Interface Control Unit refresh, and
the use of reliability centered
maintenance.




Page 139                                                                        GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The A-10’s Life-Cycle Sustainment Plan (2014) states that the Air Force performs depot inspections and repair
   of the A-10 air vehicle and engine, with the exception of Pacific Air Forces aircraft, which receive programmed
   depot maintenance and modifications under a contract with Korea Air Lines. The supply chain is managed by
   the Air Force's 448th Supply Chain Management Wing and the Defense Logistics Agency.

•   Programmed depot maintenance is performed on a 5 to 14-year cycle depending on the amount and type of
    flight hours flown by each A-10 aircraft, according to an Air Force official.

 Availability and Condition
From fiscal year 2011 through 2019, the A-10 fleet fell short of its annual aircraft availability and mission capable
goals each year except one. The A-10’s aircraft availability and mission capable rate increased slightly from fiscal
years 2011 through 2019. Both of these rates were higher by varying amounts during the time period. Air Force
officials said that the availability rate fluctuations were largely based on changes in depot inductions due to the
retirement of 61 A-10s in fiscal years 2013 and 2014 and the service’s proposals in fiscal years 2015 through 2017
to divest the entire A-10 fleet. 2 Additionally, in fiscal years 2016 and 2017, the Air Force temporarily removed 18
aircraft from service. According to Air Force officials, the mission capable rate variations were due, in part, to
traditional aging aircraft concerns and resource decisions tied to the proposed divestiture.

From fiscal years 2011 through 2019, the A-10’s rates for not mission capable maintenance and not mission
capable both maintenance and supply decreased slightly and it’s not mission capable supply rate increased slightly.
Specific details on mission capable and not mission capable rates were omitted because the information was
deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal years 2011 through 2018, the A-10’s total O&S costs decreased from $2.22 billion to $1.63 billion.
According to Air Force officials, this decrease was due to many reasons, including:
   • The Air Force reduced the A-10 fleet by retiring 61 high flying hour aircraft in fiscal years 2013 and 2014.
   • In fiscal years 2015 through 2017, the Air Force proposed that an entire A-10 fleet be divested. Although the
        fleet divestiture was not approved by Congress, the Air Force reduced the amount of funds that were
        programmed for sustaining support and continuing system improvements. This included canceling additional
        investments in new wings.
   • The Air Force temporarily removed 18 aircraft from service in late fiscal year 2015 through fiscal year 2017
        and reallocated personnel and resources to other priority Air Force needs.

Although maintenance costs also decreased during the time period, these costs increased in fiscal years 2017 and
2018 from a low in fiscal year 2016. According to officials, depot maintenance costs increased as a result of the
aircraft with older wings that were more costly to maintain. (At the end of fiscal year 2018, they said that 164 aircraft
had received new wings.) Also, officials said that depot maintenance costs increased due to a rise in depot
inductions after substantial funding cuts were made in fiscal year 2015 due to the proposed divestiture. While O&S
costs decreased from fiscal years 2011 through 2018, aircraft availability and mission capable rates fluctuated.
Officials stated that O&S costs can have a significant effect on aircraft availability. For example, they said that during
years when a divestiture is proposed, investment in depot maintenance is often reduced, resulting in fewer aircraft
being inducted, which can significantly improve the aircraft availability rate because more aircraft are available for
operations and training since they are not in depot maintenance. According to the officials, this occurred in fiscal
years 2012 and 2015.




2GAO,   Force Structure: Better Information Needed to Support Air Force A-10 and Other Future Divestment Decisions, GAO-16-816
(Washington, D.C.: Aug. 24, 2016). GAO found, among other things, that DOD and the Air Force did not have quality information on the
full implications of A-10 divestment, including gaps that could be created by A-10 divestment and mitigation options.

Page 140                                                                                 GAO-21-101SP Weapon System Sustainment
A-10 Total Operating and Support Costs




From fiscal years 2011 through 2018, the A-10’s total O&S costs per aircraft decreased from $6.41 million to $5.78
million and maintenance costs per aircraft decreased from $1.75 million to $1.70 million per aircraft. During the
same time frame, the total A-10 fleet size decreased from 346 to 282, or by 64 aircraft.




Page 141                                                                      GAO-21-101SP Weapon System Sustainment
A-10 Operating and Support Costs per Aircraft and Fleet Size




 Sustainment Challenges and Mitigation Actions
Aging: According to officials, most aging-related challenges facing the A-10 involve the aircraft’s structure, including
the wings, fuselage, and flight controls. Examples of mitigation plans include the purchase of new A-10 wings to
address economic repair and service-life requirements; completion of permanent fuselage repairs during
programmed depot maintenance to affordably reach warfighter service-life targets; and redesign of critical
components like the Central Interface Control Unit—which integrates aircraft functions and capabilities—to improve
reliability.

Maintenance: Maintenance challenges are often tied to aging, supply support and related issues that typically
manifest themselves in greater investments of time and resources to complete critical tasks such as phase
inspections and gun and engine maintenance. A-10 program officials stated that they attempt to continuously
improve the risk-based scheduling of aircraft for depot inductions in order to safely and cost-effectively expand the
programmed depot maintenance intervals. On average, program officials report that these efforts have increased
the time between programmed depot maintenance inductions by 750 hours per aircraft. Additionally, program
officials said they have an active reliability centered maintenance program that began in fiscal year 2017 and they
expect this program to increase the number of hours in the A-10 inspection cycle between inspections by 100 (from
500 to 600 hours) starting in fiscal year 2020. Prior reliability centered maintenance efforts reduced the total number
of maintenance work hours for recurring inspections by over 100,000 hours from fiscal year 2008 through fiscal year
2014, according to officials.

Supply Support: The A-10 program office stated that supply support has been a challenge for the A-10. In
particular, the A-10 has experienced issues associated with diminishing manufacturing sources, raw material
availability, reliability degradation of parts, and unforeseen, one-off issues related to a particular part. To mitigate
these supply issues, the A-10 program office and its Air Force and Defense Logistics Agency supply chain partners
have taken various actions, including end-of-life buys, incentivized contracts, redesigns of existing parts, and the
design and procurement of new parts incorporating more modern components.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate. Further, the program office reiterated that, since fiscal year 2011, the A-10 has
experienced significant turbulence and uncertainty tied to actual and proposed divestitures and the entire Air Force
A-10 enterprise and its industry partners have worked to mitigate impacts and maximize aircraft availability and
Page 142                                                                          GAO-21-101SP Weapon System Sustainment
mission capable rates. Officials said that sustainment challenges are expected to persist through fiscal year 2023
when significant investments in new wings and an improved Central Interface Control Unit will recapitalize the fleet,
and prepare it for operations into the 2030s.




Page 143                                                                        GAO-21-101SP Weapon System Sustainment
                                     F-15C/D Eagle Sustainment Quick Look
                                     Common Name: F-15C/D
                                     Lead Service: Air Force

                                     Background
Program Essentials                   The F-15C/D Eagles are all-weather, maneuverable, tactical single-seat
                                     fighters (F-15C) and two-seat fighters (F-15D) designed to perform air-to-air
Manufacturer: McDonnell
                                     combat missions. The F-15 C/D has electronic systems and weaponry to
Douglas (acquired by Boeing)
                                     detect, acquire, track and attack enemy aircraft while operating in friendly or
Sustainment: Depot maintenance       enemy-controlled airspace. The F-15C/D models were last produced in 1989.
conducted at Warner Robins Air
Logistics Complex, Georgia, and      Life Cycle of the F-15C/D
Korean Air Lines, Gimhae Korea;
field maintenance performed by
Air Force maintainers and
contractors at overseas locations
Program Office: Robins Air Force
Base, Georgia
Fiscal Year 2019 Data
                                     Overview
Average age: 35 years
                                     The F-15C/D fleet met or exceeded its aircraft availability goals for 3 of the 9
Average lifetime flying hours:       fiscal years from fiscal years 2011 through 2019, but did not meet any of its
8,558 hours per aircraft             annual mission capable goals. The F-15C/D’s aircraft availability rate and
                                     mission capable rate both increased during the time period. Total operating
Depot maintenance activity           and support (O&S) costs decreased from about $1.88 billion in fiscal year
and squadron locations:              2011 to about $1.39 billion in fiscal year 2018 due to significant decreases in
                                     unit operations and indirect support costs over this period. As a result, the
                                     annual O&S costs per aircraft decreased from $7.53 million to $5.90 million
                                     over the time period. Further, in fiscal year 2018, maintenance costs per
                                     aircraft accounted for about 41 percent of the total O&S costs per aircraft.

                                     F-15C/D Sustainment Status




Sustainment Challenges
and Mitigation Actions
The F-15C/D faces challenges with
aging, increased maintenance,
and decreased supply parts.
Mitigation actions include
extending its service life, and
working with the Defense Logistics
Agency to improve parts
availability.



Page 144                                                                       GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The F-15 program office has implemented a strategy for addressing aircraft modifications that primarily consists
   of implementing major modifications during programmed depot maintenance at Warner Robins Air Logistics
   Complex and at Korean Air Lines, for aircraft located at Kadena Air Base, Japan.

•   The F-15 Program Office has developed and begun to implement an aircraft availability improvement plan that
    includes several initiatives. For example, in order to increase the number of aircraft available to squadrons for
    training and operations, the program office has an ongoing effort to reduce the number of F-15C/D aircraft in
    programmed depot maintenance. The program office is also working to improve the reliability and maintainability
    of key components, such as the integrated drive generator that generates electrical power for the aircraft.

•   According to program officials, the Air Force has changed the planned retirement date of the F-15C/D fleet
    several times—currently the sunset year is 2045. It has also changed the number of F-15C/Ds that would be
    retired as the Air Force’s overall force-structure requirements have changed. Officials also noted that this
    uncertainty about the future size of the fleet makes it difficult to plan the procurement of spare parts and the
    repair and overhaul of the aircraft and its components.


Availability and Condition
(FOUO) The F-15C/D fleet met or exceeded its aircraft availability goals for 3 of the 9 fiscal years from fiscal year
2011 through fiscal year 2019, but it did not meet its mission capable goals for any of those years. The F-15C/D’s
aircraft availability rate and mission capable rate both increased during the time period. According to program
officials, the aircraft availability and mission capable rates were at their lowest in fiscal year 2011 due to F-15C/D
manning challenges as avionics trained technicians shifted to maintaining the F-22 fleet, reductions in the F-15C/D
combat air force fleet—including transfers to the Air National Guard—and radar upgrades that increased
unscheduled maintenance downtime.

From fiscal year 2011 through fiscal year 2019, the rates decreased for not mission capable maintenance (NMCM),
not mission capable supply (NMCS) and not mission capable both (NMCB) maintenance and supply, but the NMCS
and NMCB rates decreased only slightly. The NMCM rate was the largest factor affecting the mission capability of
the F-15C/D fleet during this time frame and was the highest in fiscal year 2011 due to validation requirements for
cracks in the longeron (i.e., a longitudinal structural component of an aircraft's fuselage), which increased
unscheduled maintenance hours, and contributed to the manning challenges and combat air fleet reductions
discussed above. Specific details on mission capable and not mission capable rates were omitted because the
information was deemed by DOD to be sensitive.


 Operating and Support Costs
Total O&S costs for the F-15C/D fleet decreased from about $1.88 billion in fiscal year 2011 to about $1.39 billion in
fiscal year 2018 in part due to a reduction in the size of the F-15C/D fleet over the timeframe. According to officials,
the largest driver of O&S costs has been depot-level reparables and consumable parts, which have had the most
direct impact to aircraft availability and mission capable rates. Officials also stated that the majority of fluctuations in
depot maintenance costs can be attributed to rate changes in the working capital fund. Officials added that any
variations to these numbers can and most likely will impact the rate (i.e., price) charged from year to year by the
Warner Robins Air Logistics Complex for conducting depot maintenance.




Page 145                                                                            GAO-21-101SP Weapon System Sustainment
F-15C/D Total Operating and Support Costs Compared




The total number of aircraft in the F-15C/D fleet decreased slightly from 250 in fiscal year 2011 to 235 in fiscal year
2018. Additionally, total O&S costs per aircraft decreased from $7.53 million to $5.90 million per aircraft and
maintenance cost per aircraft decreased from $2.91 million to $2.41 million during this time period.




Page 146                                                                          GAO-21-101SP Weapon System Sustainment
F-15C/D Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging and Maintenance: As the F-15C/D continues to age, many top-level Air Force officials question whether the
aircraft can continue to effectively meet its air superiority mission, given structural fatigue issues that have affected
the fuselage and wings. The program office recently completed a comprehensive full-scale fatigue test, which ran for
several years and identified key structural areas that will have to be inspected frequently and eventually replaced as
the F-15C/D ages. All F15C/Ds, due to age, will require a considerable amount of maintenance on the longerons
and other associated structural components. Maintenance man-hours are also increasing as the aircraft ages
because some major systems and components have become less reliable. For example, the program office, through
its reliability and maintainability program, identified two key systems—the integrated drive generator and stability
and flight control devices—needing improvement. The Aircraft Availability Improvement Plan identifies initiatives that
are being implemented to increase the reliability of these aircraft systems.

Supply Support: Supply support has also been an issue for the F-15C/D fleet due in part to decreasing supply
sources for parts that rely on older technology, according to program officials. Program officials told us they have
been working with the Air Force Sustainment Center and the Defense Logistics Agency to identify key structural
components that will need to be procured ahead of time to ensure the parts are available when the aircraft needs
them. In addition, program officials stated that the Air Force Sustainment Center has dedicated $104 million to
increasing the inventory of parts that are considered critical. Officials added that the Defense Logistics Agency has
also increased stock levels for consumable parts and expanded its existing F-15 parts contract with Boeing.


 Program Office Comments
(FOUO) In commenting on a draft of this assessment, the F-15 program office stated that although the F-15C/D fleet
has not met its aircraft availability goals in recent years, the preponderance of the related readiness reduction is a
result of aircraft structural challenges due to numerous longeron cracks in the airframe. Officials stated that the
decision to replace longerons fleet wide will mitigate the fleet risk, resulting in lower non-aircraft availability and
increased fleet combat readiness. Officials also stated that they remain committed to driving down F-15 total O&S
costs and reducing aircraft non-availability by implementing the Aircraft Availability Improvement Plan initiatives in
the maintenance, supply and depot non-availability categories, and to support mission requirements until the Air
Force retires the aircraft. The program office also provided technical comments which we incorporated where
appropriate.


Page 147                                                                          GAO-21-101SP Weapon System Sustainment
                                     F-15E Strike Eagle Sustainment Quick Look
                                     Common Name: F-15E
                                     Lead Service: Air Force

                                     Background
Program Essentials                   The F-15E Strike Eagle is a dual-role fighter designed to perform air-to-air
                                     and air-to-ground missions. An array of avionics and electronics systems
Manufacturer: Boeing
                                     gives the F-15E the capability to fight at low altitude, day or night, and in all
Sustainment: Depot Maintenance       weather. It was first manufactured in 1986 and was declared fully operational
conducted at Warner Robins Air       in 1994.
Logistics Complex, Georgia, and
field maintenance performed by       Life Cycle of the F-15E
Air Force personnel
Program Office: Robins Air Force
Base, Georgia
Fiscal Year 2019 Data
Average age: 27.04 years
Average lifetime flying hours:
                                     Overview
7,685 hours per aircraft
                                     The F-15E fleet exceeded its aircraft availability goals in 2 of the 9 fiscal
Depot maintenance activity           years from fiscal years 2011 through 2019, and met or exceeded its mission
and squadron locations:              capable goals in 4 of the 9 years. The F-15E’s aircraft availability rate and
                                     mission capable rate decreased during the time period. Total operating and
                                     support (O&S) costs decreased from about $2.19 billion in fiscal year 2011 to
                                     about $1.87 billion in fiscal year 2018 due to decreases in unit operations,
                                     maintenance, and unit-level manpower costs. Over this same time frame, the
                                     total number of aircraft decreased and the annual O&S costs per aircraft
                                     decreased from $9.92 million to $8.56 million. In fiscal year 2018,
                                     maintenance costs per aircraft accounted for about 37 percent of the total
                                     O&S costs per aircraft.

                                     F-15E Sustainment Status




Sustainment Challenges
and Mitigation Actions
The F-15E faces challenges with
aging, increased maintenance,
and obtaining needed parts.
Mitigation actions include
extending its service life and
working with the Defense Logistics
Agency to improve parts
availability.




Page 148                                                                       GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The F-15 program office has a sustainment strategy for the F-15E that includes implementing major
   modifications during programmed depot maintenance at Warner Robins Air Logistics Complex. Expanded shifts
   for contract field teams performing modification installs are planned in order to reduce aircraft downtime.

•   The F-15 program office has developed and begun to implement an aircraft availability improvement plan for
    fiscal years 2019-2024 that includes several initiatives to improve the availability of the aircraft, such as
    initiatives to improve the availability of spare parts and the reliability of some key systems on the aircraft.

Availability and Condition
The F-15E fleet exceeded its aircraft availability goals for 2 of the 9 fiscal years from fiscal year 2011 through fiscal
year 2019, and met or exceeded its mission capable goals for 4 of the 9 years during that period. The F-15E’s
aircraft availability rate and mission capable rate decreased during the time period. The F-15E aircraft availability
improvement plan states that the current decline in availability is significant when compared to the historical norm.
The plan concluded that achieving future aircraft availability goals is unlikely due to significant increases in F-15E
modifications through the 2020s, namely the electronic warfare upgrade, which is the largest modification ever to the
aircraft. Additionally, program officials said the aircraft availability and mission capable rates were impacted by
fluctuations in the number of aircraft in depot, radar upgrades on all aircraft that has increased time in depot, and
slightly higher than planned time awaiting supply parts.

From fiscal years 2011 through 2019, the F-15E’s rate increased slightly for not mission capable maintenance
(NMCM) and the rates decreased slightly for not mission capable for supply (NMCS) and not mission capable both
(NMCB) maintenance and supply. According to program officials, the primary drivers for the recent NMCM rate
increase were: the fuel system; airframe, weapons delivery and flight controls; special inspections in support of
deployments, and rebuild and maintenance efforts. According to program officials, the largest driver of the aircraft
not being mission capable was maintenance issues, such as challenges with the ejection seats and environment
control systems. Program officials also said that key aircraft components, such as the integrated drive generators
that provide electrical power for the aircraft, and stability and flight control devices are the traditional drivers for the
not mission capable for supply rates because more time is needed to stand up a new production line for the
generators and more time needed to procure new overhaul and repair kits with redesigned components for the
stability and flight-control devices. Specific details on mission capable and not mission capable rates were omitted
because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
Total O&S costs for the F-15E fleet decreased from approximately $2.19 billion in fiscal year 2011 to about $1.87
billion in fiscal year 2018. The largest drivers of O&S cost were maintenance and unit level manpower during the
time period. With respect to maintenance costs, the largest categories were depot-level reparables and depot
maintenance. Officials attributed the majority of fluctuations in depot-maintenance costs to rate changes in the
working capital fund. The officials explained that variations to these numbers impact the rate (i.e., price) charged
from year to year by the Warner Robins Air Logistics Complex for conducting depot maintenance.




Page 149                                                                             GAO-21-101SP Weapon System Sustainment
F-15E Total Operating and Support Costs




The F-15E fleet consists of 218 aircraft to meet the fleet’s operational requirements. While the total number of
aircraft in the F-15E fleet remained fairly constant from fiscal years 2011 through 2018, the total O&S costs per
aircraft decreased. Specifically, the O&S costs per aircraft decreased from $9.92 million to $8.56 million during this
time period. In addition, maintenance costs per aircraft decreased from $3.83 million to $3.15 million during the
same time frame.




Page 150                                                                         GAO-21-101SP Weapon System Sustainment
F-15E Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: As the F-15E ages, structural issues have been identified that affect the fuselage and wings. The program
office recently completed a comprehensive full-scale fatigue test that ran for several years and identified key
structural areas that will have to be inspected more frequently and eventually replaced as the F-15E ages.

Maintenance: The program office has an effort to reduce the number of F-15E aircraft in planned depot
maintenance to 24 in fiscal year 2019, which is 12 aircraft less than the number of depot inductions in fiscal year
2018. According to program officials, this is a one-time action that addresses fiscal year 2019 depot inductions only
and reflects the decision to help improve the depot capacity losses that occurred in fiscal year 2019 due to the
increased condemnation rate of F-15C/D longerons and the non-availability of new longerons to replace them, which
resulted in delays to F-15E programmed depot maintenance inductions. Officials stated that the F-15E depot-
focused improvement initiative is an Aircraft Availability Improvement Plan initiative to extend the programmed depot
maintenance interval from 6 years to 7.5 years beginning in the first quarter of fiscal year 2020, which would reduce
the number of depot inductions by up to four aircraft per year. Additionally, the F-15E aircraft availability
improvement plan states that the integrated drive generators and the stability and flight-control devices have
become increasingly less reliable. The plan identifies initiatives that are in place to increase the reliability of these
aircraft systems, which are projected in the future to improve the aircraft availability rates.

Supply Support: Supply support has also been an issue for the F-15E fleet due in part to decreasing supply
sources for parts that rely on older technology, according to officials. Program officials told us they have been
working with the Air Force Sustainment Center and the Defense Logistics Agency to identify key structural
components that will need to be procured ahead of time to ensure the parts are available when the aircraft needs
them. In addition, program officials stated that the Air Force Sustainment Center has dedicated $104 million to
increasing the inventory of parts that are considered critical. Officials added that the Defense Logistics Agency has
increased stock levels for consumable F-15 parts and expanded its existing parts contract with Boeing.

Program Office Comments
In commenting on a draft of this assessment, the F-15 program office stated that they concur with our observations.
The program office also provided technical comments, which we incorporated where appropriate.



Page 151                                                                          GAO-21-101SP Weapon System Sustainment
                                       .
                                       F-16 Fighting Falcon Sustainment Quick Look
                                       Common Name: F-16
                                       Lead Service: Air Force

                                       Background
Program Essentials                     The F-16 Fighting Falcon is a compact, single-engine, multirole fighter
Manufacturer: Lockheed Martin          aircraft first manufactured in 1978. It is a highly maneuverable aircraft with
Sustainment: Depot maintenance         single- and two-seat models that participates in air-to-air combat and air-to-
conducted at Ogden Air Logistics       surface attack missions.
Complex, Utah, and contract
depots in Belgium and South            Life Cycle of the F-16
Korea; and field maintenance
conducted by Air Force
maintainers and contractors
Program Office: Hill Air Force
Base, Utah
Fiscal Year 2019 Data
Average age: 29 years
Average lifetime flying hours:         Overview
7,099 hours per C model aircraft       From fiscal years 2011 through 2019, the F-16 fleet met or exceeded its
and 6,368 hours per D model            annual aircraft availability goals in 4 of the 9 years, but did not meet any of its
aircraft                               mission capable goals during this time frame—including its Department of
Depot maintenance activity             Defense mission capable goal for fiscal year 2019. The F-16’s aircraft
and squadron locations:                availability rate and mission capable rate decreased slightly during the time
                                       period. Total operating and support (O&S) costs for the fleet decreased from
                                       about $5.17 billion in fiscal year 2011 to about $4.07 billion in fiscal year
                                       2018 in part because the number of aircraft decreased. In fiscal year 2018,
                                       the O&S costs per aircraft were $4.33 million with about $1.32 million per
                                       aircraft (or 31 percent) spent on maintenance issues.

                                       F-16 Sustainment Status




 Sustainment Challenges
 and Mitigation Actions
Some F-16 aircraft are operating
beyond their expected service life
with maintenance and supply
challenges. Planned actions to
mitigate these challenges include
extending the service life of the
aircraft, identifying all parts that
need to be replaced during the
inspection phase of maintenance,
and identifying alternate vendors
for parts.
Page 152                                                                          GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The F-16 Fighting Falcon Weapon System Life-Cycle Sustainment Plan (2017) documents the operations
  and support planning for the F-16, including strategies to keep the weapon system reliable, maintainable,
  affordable, and supportable through its projected life cycle.
• Aircraft depot-level maintenance and field-level maintenance is performed by both Air Force maintainers and
  contractor personnel.
• The Air Force implemented a Service Life Extension Program in 2011 to extend the service life of 300 F-16
  aircraft from 8,000 to 13,856 flying hours by (1) identifying life-limiting structural components through durability
  testing and analysis, (2) developing modifications and repair designs, and (3) validating the modifications and a
  repair kit. The modifications and repairs are planned through 2029 and, as of December 2019, the estimated
  cost was $1.1 billion.

 Availability and Condition
From fiscal year 2011 through fiscal year 2019, the F-16 fleet met or exceeded its aircraft availability goals in 4 of
the 9 years and came close to meeting its goals in 4 additional years. However, the F-16 missed its mission capable
goals every year during this period—including its Department of Defense mission capable goal for fiscal year 2019.
According to program officials, the F-16’s inability to meet its mission capable goals is due in part to the age of the
fleet and related supply and maintenance challenges. The F-16’s aircraft availability rate and mission capable rate
decreased slightly during the time period.

Between fiscal year 2011 and fiscal year 2019, the rates for not mission capable maintenance (NMCM) and not
mission capable supply slightly increased, while the not mission capable both maintenance and supply rate slightly
decreased. According to officials, these not mission capable rates were influenced by multiple factors, including
operations tempo, training, manning levels, support equipment and parts availability. Officials also stated that two of
the top NMCM rate drivers were engine inlets and phase inspections. The specific details on mission capable and
not mission capable rates were omitted because the information was deemed by DOD to be sensitive.

 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the F-16’s total O&S costs decreased from about $5.17 billion to
about $4.07 billion, primarily due to a decrease in the total number of aircraft, according to officials. Maintenance
was the second largest O&S cost category behind unit-level manpower. According to program officials, increased
maintenance costs in fiscal years 2014, 2015, and 2017 were due to out-of-cycle depot repairs and the replacement
of structural components and radar-absorbent material on the aircraft. Depot-level reparables, the most significant
category of maintenance costs, averaged about $786.85 million a year, while consumable materials and repair parts
averaged $267.27 million a year from fiscal years 2011 through 2018.




Page 153                                                                         GAO-21-101SP Weapon System Sustainment
F-16 Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the O&S costs per F-16 aircraft generally decreased from about
$5.07 million to about $4.33 million. According to officials, this was a result of the decrease in aircraft inventory from
1,019 aircraft in fiscal year 2011 to 940 aircraft in fiscal year 2018. This decrease occurred due to the retirement of
older aircraft in the fleet. On average, maintenance costs per aircraft were about $1.28 million (or about 28 percent)
of total O&S costs per aircraft during this time period.




Page 154                                                                           GAO-21-101SP Weapon System Sustainment
F-16 Operating and Support Costs per Aircraft and Fleet Size




 Sustainment Challenges and Mitigation Actions
Aging: The Air Force plans to keep some of its F-16 fleet flying until 2046 through a service-life extension. The
service-life extension is vital to maintaining the Air Force’s air superiority mission, since officials explained that F-
35 aircraft are not being delivered as quickly as originally anticipated. The Air Force’s ongoing and planned
actions include extending the service life of 300 F-16 aircraft by 5,856 flying hours beyond its planned 8,000
flying-hour service life, using a phased approach. This Service-Life Extension Program began in December 2016
and is scheduled to last through 2029 at an estimated cost of $1.1 billion as of December 2019. According to
program officials, this service-life extension program does not guarantee that all the aircraft will be able to fly
until 2046.

Maintenance: Officials stated that, as the F-16 ages, it is requiring additional maintenance for repairs that were
not originally planned, such as replacing the bulkhead (i.e., a dividing wall or barrier between compartments in a
an aircraft), longerons (i.e., a longitudinal structural component of an aircraft's fuselage), and skins (i.e., repair of
major structural elements that may exhibit areas of cracking related to stress concentrations and number of flight
hours on the aircraft). Therefore, maintenance activities are taking longer, and aircraft downtime has increased.
The Air Force’s ongoing and planned actions include mitigation efforts to counter corrosion by identifying all parts
and components that need to be repaired and replaced during the phase and depot inspections, and discussion of
issues at F-16 Health of Fleet meetings held monthly to identify causes and possible solutions.

Supply Support: The F-16 is experiencing shortages of parts because of diminishing manufacturing sources
and increasing need for low-demand items. The Air Force’s ongoing and planned actions include identifying
alternate vendors, reverse engineering of parts, and cannibalizing parts from other aircraft.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 155                                                                            GAO-21-101SP Weapon System Sustainment
                                      F-22 Raptor Sustainment Quick Look
                                      Common Name: F-22
                                      Lead Service: Air Force

                                      Background
Program Essentials                    The F-22 Raptor is one of the newest Air Force aircraft. The F-22 performs
                                      air-to-air and air-to-ground missions and is designed to attack enemy aircraft
Manufacturer: Lockheed Martin
                                      and ground targets at great distances.
and Pratt & Whitney (engines)

Sustainment: Lockheed Martin          Life Cycle of the F-22
provides sustainment support.
Ogden Air Logistics Complex,
Utah, provides depot
maintenance. Air Force
maintainers provide field
maintenance.

Program Office: Wright-Patterson
Air Force Base, Ohio                  Overview
Fiscal Year 2019 Data                 The F-22 fleet did not meet its annual aircraft availability or mission capable
                                      goals for any year from fiscal years 2011 through 2019 and did not meet the
Average age: 12 years
                                      Department of Defense’s mission capable goal for fiscal year 2019. Both the
Average lifetime flying hours:        F-22’s aircraft availability and mission capable rates decreased during the
1,866 hours per aircraft              nine year period. Total operating and support (O&S) costs increased from
                                      about $2.34 billion in fiscal year 2011 to about $2.42 billion in fiscal year
Depot maintenance activity            2018. Furthermore, maintenance costs—the largest share of O&S costs—
and squadron locations:               increased by a total of $556.21 million during this period. Total O&S costs per
                                      aircraft decreased from $14.34 million in fiscal year 2011 to $13.27 million in
                                      fiscal year 2018 and an average of about 54 percent was dedicated to
                                      maintenance costs.

                                      F-22 Sustainment Status




Sustainment Challenges
and Mitigation Actions
The F-22 faces challenges with its
low-observable system and spare
parts. The Air Force is contracting
to increase low observable repair
capacity and securing additional
funding for spare parts.




Page 156                                                                       GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The 2017 F-22 Life-Cycle Management Plan, in conjunction with the Engine Life Management Plan, codifies the
   sustainment strategy for the F-22 program. It guides logistics sustainment and modernization strategy execution
   within the F-22 program and support organizations, and communicates the strategy to Air Force leadership.

•   The F-22 program office has a performance-based logistics contract with Lockheed Martin for overall aircraft
    sustainment. The Air Force conducts depot maintenance under a public/private partnership agreement with
    Lockheed Martin. Pratt & Whitney provides engine sustainment at Tinker Air Force Base, Oklahoma.

•   The program office has various initiatives to support sustainment, such as maintaining a comprehensive
    diminishing manufacturing sources program and proactively supporting the continued sustainment of component
    parts of the aircraft through various replacement programs, such as the F-22 Reliability and Maintainability
    Program. This initiative is an ongoing effort to drive continuous improvement in availability.


 Availability and Condition
The F-22 fleet did not meet its annual goals for either the aircraft availability or mission capable rate for any year
from fiscal year 2011 through fiscal year 2019, including the Department of Defense’s 80 percent mission capable
goal for fiscal year 2019. Both the F-22’s aircraft availability and mission capable rates decreased during the nine
year period. According to program officials, the F-22’s low aircraft availability and mission capable rates were tied to
degradation of the aircraft’s low-observable system coating, supply shortages, and execution of higher-than-
budgeted flying hours. Officials stated that after 2017 the Air Force devoted additional funding for the F-22 to help
procure time-sensitive spares, repairs, and consumable parts.
From fiscal year 2011 through fiscal year 2019, the rates increased slightly for not mission capable maintenance
(NMCM) and not mission capable supply (NMCS), while the not mission capable both (NMCB) maintenance and
supply rate decreased slightly. According to program officials, the NMCM rate increased in part due to quality control
issues in the low-observable system inspection process and low-observable maintenance continues to drive the
NMCM rate. Program officials also stated that the devastation caused by Hurricane Michael to Tyndall Air Force
Base, Florida—the primary location for F-22 pilot training—and the F-22’s supply chain, maintenance and flying
operations, increased the NMCM rate. Specific details on mission capable and not mission capable rates were
omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
Total O&S costs increased from about $2.34 billion in fiscal year 2011 to about $2.42 billion in fiscal year 2018.
According to program office officials, this increase in O&S costs was due to increased flying-hour execution and
scheduled engine depot inductions. Maintenance costs—the largest share of O&S costs during the time period—
increased from $1.04 billion to $1.59 billion. From fiscal year 2015 through fiscal year 2018 there was a constant
increase in maintenance costs due to increases in contractor logistics support costs.




Page 157                                                                          GAO-21-101SP Weapon System Sustainment
F-22 Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the total O&S costs per F-22 aircraft varied. The highest O&S costs
per aircraft was about $14.34 million in fiscal 2011 and the lowest O&S costs per aircraft was $10.64 million in fiscal
year 2014. In fiscal year 2018, the total O&S costs per aircraft was $13.27 million. While the number of aircraft in the
F-22 fleet remained fairly stable since fiscal year 2014, there was an increase in O&S costs per aircraft since 2014
due to the consistent increase in the maintenance costs per aircraft during this same period. Since fiscal year 2014,
maintenance costs increased from $5.06 million per aircraft to $8.75 million in fiscal year 2018 and accounted for
about 59 percent of the total O&S costs per aircraft. According to program officials, the increase in maintenance
costs per aircraft was due to a 30 to 50 percent increase in flying hours during this period.




Page 158                                                                         GAO-21-101SP Weapon System Sustainment
F-22 Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging and Maintenance: As the F-22 ages, it requires additional maintenance for repairs related to corrosion and
the aging of its low-observable coating. Program officials stated that the low-observable coating degradation began
expanding to areas of the aircraft at a faster pace than unit maintenance could control, driving a major spike in
maintenance required to preserve the overall health of the aircraft. Program officials told us that the Air Force has
ongoing and planned actions to counter (1) corrosion, by identifying all parts that need to be repaired and replaced
during the inspection phase; and (2) the low observable issue, by depot reversion repair and opening an additional
repair line facility to handle the increased number of unplanned inlet coating repairs. Program officials added that
the Air Force has been piloting a robotic solution to apply the low-observable coating that has been working well and
has helped address their skilled worker shortage.

Supply Support: According to program officials, the F-22 experienced shortages of parts from 2014 through 2018
because flying operations exceeded allocated budgets in 4 of 5 years and vendors that supply parts did not have
lay-in materiel to address the magnitude of increased flying hours. Program officials noted when major unplanned
changes occur in forecasted flying hours, it creates negative effects on the supply networks. Program officials told
us they are (1) maintaining a comprehensive diminishing manufacturing sources program to minimize material
shortages and (2) receiving out-of-cycle supply funding increases to improve supply issues. Further, program
officials stated that the fundamental shift from a cost-plus-fixed fee to cost-plus-incentive fee contract for supply
services will yield cost savings through 2022.

Program officials also stated that they are implementing efforts to improve the F-22 mission capable rate by the end
of fiscal year 2019, including improving spare-parts management; increasing maintenance capacity to accelerate
needed aircraft repairs; and enhancing training and proficiency to improve the generation of mission-ready aircraft.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 159                                                                         GAO-21-101SP Weapon System Sustainment
Page 160   GAO-21-101SP Weapon System Sustainment
                                    AH-64 Apache Sustainment Quick Look
                                    Common Name: AH-64
                                    Lead Service: Army

                                     Background
Program Essentials                  The AH-64 Apache is an attack helicopter that was first manufactured in
Manufacturer: Boeing Company        1984 as the AH-64A and later re-manufactured as the AH-64D in 1997. The
Integrated Defense Systems          models of the Apache currently in use, the AH-64D and AH-64E, can perform
                                    a variety of missions including ground force security, fixed based operations,
Sustainment: Boeing and the         aerial escorts, reconnaissance, and single or multiple enemy combatant
Army sustain the airframe and       engagements.
Lockheed Martin sustains the
sensors                             Life Cycle of the AH-64
Program Office: Redstone
Arsenal, Alabama
 Fiscal Year 2019 Data
Average age: 11.6 years (AH-
64D); 3.4 years (AH-64E)
Average lifetime flying hours:      Note: Many of the AH-64Ds were rebuilt from the original AH-64A models, which were first
5,574 hours (AH-64D); 1,236         manufactured in 1985.
hours (AH-64E)
Depot maintenance activity           Overview
and combat aviation brigade         From fiscal year 2011 to fiscal year 2019, the AH-64 fleet did not meet its
locations:                          mission capable goal. According to Army officials, not mission capable rate
                                    trends were due to spare parts quality and reliability issues, which required
                                    replacement and maintenance actions. Operating and support (O&S) costs
                                    per aircraft decreased from about $1.89 million in fiscal year 2011 to $1.71
                                    million in fiscal year 2017.

                                    AH-64 Sustainment Status




Sustainment Challenges
and Mitigation Actions
The Army is upgrading its AH-
64Ds to AH-64Es to improve
capability and reduce unscheduled   Note: We obtained fiscal year 2018 operating and support (O&S) cost data from the Army, but we
maintenance. In addition, the       learned from the Army that the data was inaccurate. Thus, the costs presented here for the Army
                                    aircraft are based on fiscal year 2017 O&S cost data.
Army is working to improve the
availability of spare parts.




Page 161                                                                               GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The Apache Block III Life-Cycle Sustainment Plan (2012) documents plans to execute the upgrade program for
   the AH-64. The plan focuses on delivering warfighter required capabilities and implementing a comprehensive
   support strategy to support near-term and future sustainment strategy decisions. According to officials, the AH-
   64 program office is currently drafting a new version of the sustainment plan that will incorporate follow-on test
   and evaluation results and updated performance-based logistics contracts numbers. There was no planned
   release date for the sustainment plan at the time of this review.

•   To provide sustainment support to the AH-64, the Army entered into performance-based logistics contracts with
    Boeing and Lockheed Martin. Boeing and the Army are responsible for supporting the sustainment of the
    airframe and Lockheed Martin provides sustainment support for the AH-64’s sensors. Under these contracts,
    Boeing and Lockheed Martin provide management of the supply chain, maintenance, transportation,
    configuration, and reliability and obsolescence. Further, Boeing is responsible for establishing and conducting
    Army depot maintenance capability for the AH-64E.

•   According to officials, the AH-64 has various initiatives to support sustainment, such as addressing acquisition
    lead times, corrosion prevention, obsolescence issues, and intellectual property rights problems.


Availability and Condition
From fiscal year 2011 through fiscal year 2019, the AH-64 fell short of its mission capable goal each year. Further,
from fiscal year 2011 through fiscal year 2019, the not mission capable maintenance (NMCM) and not mission
capable supply (NMCS) rates varied. Officials explained that the NMCM and NMCS rate trends were due to spare
parts quality and reliability issues, which required replacement and maintenance actions. Specific details on mission
capable and not mission capable rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
The AH-64’s overall O&S costs decreased from $1.16 billion in fiscal year 2011 to about $856.23 million in fiscal
year 2017. Maintenance costs accounted for 46 percent of O&S costs over the period, and decreased overall by
$332.55 million from fiscal years 2011 through 2017. According to officials, the AH-64Ds in the worst condition were
the first aircraft to be scheduled for upgrade to the AH-64E fleet. Therefore, the officials stated that this upgrade
increased the efficiency of the overall fleet and decreased overall maintenance costs for the aircraft. Depot-level
reparables was the most significant category of maintenance costs, averaging $218.07 million per year, or 49
percent of total maintenance costs, from fiscal years 2011 through 2017. Depot maintenance costs was the smallest
share, averaging $0.38 million per year, or less than 0.1 percent of total maintenance costs, during the same time
period.




Page 162                                                                        GAO-21-101SP Weapon System Sustainment
AH-64 Total Operating and Support Costs




Note: We obtained fiscal year 2018 operating and support (O&S) cost data from the Army, but we learned from the Army that the data was inaccurate.
Thus, the costs presented here for the Army aircraft are based on fiscal year 2017 O&S data.

From fiscal years 2011 through 2017, the AH-64’s O&S costs per aircraft decreased from about $1.89 million to
$1.71 million and the mission capable rate decreased. Also, maintenance costs per aircraft, on average, accounted
for almost half of the total cost per aircraft over the same time period, averaging about $770,000 million per year.
Additionally, the number of aircraft in the fleet increased from 612 in fiscal year 2011 to 681 in fiscal year 2018.




Page 163                                                                                             GAO-21-101SP Weapon System Sustainment
AH-64 Operating and Support Costs per Aircraft and Fleet Size




Note: We obtained fiscal year 2018 operating and support (O&S) cost data from the Army, but we learned from the Army that the data was inaccurate.
Thus, the costs presented here for the Army aircraft are based on fiscal year 2017 O&S data.


 Sustainment Challenges and Mitigation Actions
Maintenance: According to program officials, delayed administrative timelines for executing repair contracts
negatively affected maintenance times for the AH-64. The Army’s ongoing actions include putting additional tools in
place to provide proper notification of expiring contracts so that Army officials can extend and quickly award
contracts before the expiration date.

Supply Support: Army officials have stated that the Army has experienced issues with parts quality that have
caused delays in repair times, delayed production timelines when procuring spare parts for the AH-64, and parts
shortages. According to officials, the program office has faced challenges related to manufacturer parts quality
issues, which led to additional maintenance actions and increased the NMCM and NMCS rates in 2017 and 2018.
To address these issues, the program office worked with manufacturers to perform required replacement and
maintenance actions reducing both the unit burden and the time required to complete corrective maintenance
actions, as well as to form a strategic plan to prevent future parts reliability issues. Additionally, officials stated they
have also faced production and repair delays of parts, which the Army has worked to mitigate by leading monthly
engagements with parts suppliers to reduce production lead times. Finally, to combat parts shortages, Army officials
stated that they continually work with Boeing and the Defense Logistics Agency to expedite deliveries to address
parts shortages affecting Corpus Christi Army Depot and commercial repair output of parts.


 Program Office Comments
In commentating on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 164                                                                                             GAO-21-101SP Weapon System Sustainment
                                      CH-47 Chinook Sustainment Quick Look
                                      Common Name: CH-47
                                      Lead Service: Army

                                      Background
Program Essentials                    The CH-47 Chinook is a heavy-lift cargo rotary wing aircraft that was first
Manufacturer: Boeing                  manufactured in 1982. It transports forces and heavy equipment to provide
                                      routine aerial sustainment of maneuver forces. Between fiscal year 2011 and
Sustainment: Depot maintenance        fiscal year 2018 there were two models of the CH-47, D and F, with program
conducted at Army depots and          office officials confirming that the D model was retired in 2018. According to
contractor sites. Field               program office officials, modernization from the CH-47D to the CH-47F
maintenance conducted by Army         began in 2004, with planned completion of a full fleet upgrade by 2022, and
personnel at the unit level.          as of 2019 there have been no D models flying.
Program Office: Project Manager
                                      Life Cycle of the CH-47
Cargo Helicopters, Redstone
Arsenal, Alabama.
 Fiscal Year 2019 Data
Average age: 6.53 years
(CH-47F)
Average lifetime flying hours:
1,285.28 hours per aircraft
(CH-47F)                              Overview
Depot maintenance activity            In fiscal year 2019, the CH-47 fleet did not meet its mission capable rate goal
and combat aviation brigade           due to maintenance and supply issues, and did not meet its goal for any year
locations:                            from fiscal year 2011 to fiscal year 2019. Unavailability due to maintenance
                                      and supply issues decreased from fiscal year 2011 to fiscal year 2019
                                      because, according to officials, the newer CH-47Fs replaced the older CH-
                                      47Ds. Additionally, operating and support (O&S) costs per aircraft decreased
                                      from about $2.07 million in fiscal year 2011 to about $1.48 million in fiscal
                                      year 2017. According to officials, maintenance costs decreased because the
                                      CH-47Fs required less unscheduled maintenance than the CH-47Ds.

                                      CH-47 Sustainment Status




Sustainment Challenges
and Mitigation Actions
The Army finished transitioning its
CH-47Ds to CH-47Fs to improve
capability and reduce unscheduled
maintenance. However, the
program office is working to          Note: We obtained fiscal year 2018 operating and support (O&S) cost data from the Army, but we
address remaining supply support      learned from the Army that the data were inaccurate. Thus, the costs presented here for the Army
issues with corrective action plans   aircraft are based on fiscal year 2017 O&S data.
and process improvements.


Page 165                                                                                 GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The CH-47F Chinook with Block II Life-Cycle Sustainment Plan (2016) documents the modernization program
   for the CH-47 and provides a product support strategy to minimize the costs and logistics footprint within the
   existing supply chain while meeting warfighter requirements. This upgrade strategy allows the CH-47 program
   office to incrementally insert technology upgrades into the CH-47F model while maintaining affordability and
   meeting requirements.

•   There was no depot maintenance program for the CH-47 between fiscal year 2011 and fiscal year 2019
    because the aircraft was being modernized, according to program office officials. The Army initially sustained
    the CH-47 with interim contractor support and then transitioned to either organic or limited performance-based
    logistics support. Field maintenance is performed by combat aviation brigade personnel.

•   According to officials, the Defense Logistics Agency and Army Aviation and Missile Command provide supply
    support for the CH-47.


Availability and Condition
From fiscal year 2011 through fiscal year 2019, the CH-47 missed its mission capable goals. However, the percent
of mission capable aircraft increased from fiscal year 2011 to fiscal year 2019 as more CH-47F aircraft were
operated and maintained. According to officials, the CH-47 missed its goals because the CH-47D—which required
more unscheduled maintenance than the CH-47F—was still in the fleet at that time. The CH-47D was no longer
flying as of 2019, and officials expect to complete the fleet upgrade to the CH-47F by 2022. From fiscal year 2011
through fiscal year 2019, the not mission capable maintenance (NMCM) rate decreased, while the not mission
capable supply (NMCS) rate remained relatively steady. Specific details on mission capable and not mission
capable rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2017, the CH-47’s total O&S costs decreased from $781.82 million to
$534.31 million, as the mission capable rate increased. Unit operations costs accounted for the largest share of
O&S costs over the period, averaging about $324.96 million per year during the same time period. Maintenance
costs decreased significantly, from $374.22 million in fiscal year 2011 to $145.48 million in fiscal year 2017.
According to officials, the older CH-47Ds required more unscheduled maintenance than did the newer CH-47Fs, so
as the fleet was upgraded, maintenance costs—and as a result overall O&S costs—decreased.




Page 166                                                                       GAO-21-101SP Weapon System Sustainment
CH-47 Total Operating and Support Costs




Note: We obtained fiscal year 2018 operating and support (O&S) cost data from the Army, but we learned from the Army that the data were
inaccurate. Thus, the costs presented here for the Army aircraft are based on fiscal year 2017 O&S data.

From fiscal year 2011 through fiscal year 2017, the CH-47’s O&S costs per aircraft decreased from $2.07 million to
$1.48 million, while mission capable rates increased. Also, maintenance costs per aircraft decreased from $0.99
million in fiscal year 2011 to $0.4 million in fiscal year 2017. According to officials, the Army was transitioning the
older CH-47Ds, which required more unscheduled maintenance, to the newer CH-47Fs during the time period.
Additionally, the number of aircraft decreased from 377 aircraft in fiscal year 2011 to 362 aircraft in fiscal year 2017;
however, according to officials, the Army plans to have 465 CH-47F aircraft—246 new builds and 219 upgraded CH-
47D models—once the upgrade process is complete in 2022.




Page 167                                                                                            GAO-21-101SP Weapon System Sustainment
CH-47 Operating and Support Costs per Aircraft and Fleet Size




Note: We obtained fiscal year 2018 operating and support (O&S) cost data from the Army, but we learned from the Army that the data were
inaccurate. Thus, the costs presented here for the Army aircraft are based on fiscal year 2017 O&S data.



 Sustainment Challenges and Mitigation Actions
Maintenance: According to program office officials, the CH-47D required more unscheduled maintenance than did
the CH-47F, which is typical for older aircraft. However, as the fleet is fully upgraded to CH-47F models, this
unscheduled maintenance is expected to decrease, resulting in greater availability of the aircraft for Combat Aviation
Brigades. In addition, according to officials, the program office began implementation of a new scheduled
maintenance plan for the CH-47F fleet in June 2019, which is based on best commercial practice and methodology.
Under this plan, officials stated that task inspection intervals have been significantly extended; for example, heavy
maintenance inspections scheduled at 200 and 400 flying hours will now be performed at 320 and 640 flying hours,
which officials expect will lead to a 2.5 percent reduction in scheduled maintenance downtime across the fleet.
According to program office officials, the goal is to have the entire CH-47F fleet under this new maintenance plan by
July 2021.

Supply Support: According to program office officials, one of the biggest sustainment challenges for the CH-47 has
been having access to low-demand, but critical, parts, such as airframe components and outer surface skins. To
mitigate this issue, officials told us that they utilize the open CH-47F production line to get parts that are causing
availability issues, and that they have had specific parts fabricated at Army Logistics Readiness Centers. Further,
supply chain management issues continue to be a problem, due to a low volume of parts in the system, long
production lead times, and delinquent deliveries, according to officials. According to officials, the program office
continues to work with Boeing and other contractors to identify high risk parts and suppliers and to implement
corrective actions for the root causes, improve processes, and develop risk mitigation strategies for each part and its
supplier. According to officials, they also have ongoing engagements with the Defense Logistics Agency, Army
Aviation and Mission Command, and Army Contracting Command, as well as with original equipment manufacturers
and suppliers, to mitigate excessive lead times and delinquent deliveries. Lastly, officials stated that managing
avionics and software systems to address obsolescence issues has been a significant challenge that is expected to
continue at an increasing rate. According to officials, the program office conducts proactive obsolescence monitoring
for components and seeks out industry support to mitigate this issue, but these re-design efforts—even if funded by
the original equipment manufacturers—are costly.




Page 168                                                                                            GAO-21-101SP Weapon System Sustainment
 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 169                                                                    GAO-21-101SP Weapon System Sustainment
                                       UH/HH-60 Black Hawk Sustainment Quick Look
                                       Common Name: Black Hawk Utility Helicopter
                                       Lead Service: Army

                                       Background
Program Essentials                     The UH/HH-60 Black Hawk is a utility tactical transport helicopter. The UH-60
                                       provides air assault, general support, command and control, and special
Manufacturer: Sikorsky Aircraft
                                       operations support to combat, stability, and support operations, and the HH-
Corporation
                                       60 is a variant that also provides aeromedical evacuation services. The HH-
Sustainment: Depot maintenance         60 and UH-60 are managed in an integrated manner due to their similarities,
conducted at the Corpus Christi        according to Army officials.
Army Depot. Field maintenance
conducted by Army personnel at         Life Cycle of the UH-60
the unit level.

Program Office: Program
Manager Utility Helicopters,
Redstone Arsenal, Alabama
Fiscal Year 2019 Data
Average age: 15.86 years               Life Cycle of the HH-60

Average number of lifetime
flying hours: 184.2 hours per
aircraft
Depot maintenance activity
and combat aviation brigade
locations:
                                       Overview
                                       The UH/HH-60 fleet did not meet its mission capable goal in any year from
                                       fiscal year 2011 through 2019. However, the percent of mission capable
                                       aircraft increased from fiscal year 2011 to year 2019. Operating and support
                                       (O&S) costs per aircraft decreased, from about $1.06 million in fiscal year
                                       2011 to $0.76 million in fiscal year 2017.

                                       UH/HH-60 Sustainment




Sustainment Challenges
and Mitigation Actions
The UH/HH-60 fleet faces parts
supply challenges. Officials are
implementing actions to improve
the acquisition and quality of spare
parts.
                                       Note: We obtained fiscal year 2018 operating and support (O&S) cost data from the Army, but we
                                       learned from the Army that the data were inaccurate. Thus, the costs presented here for the Army
                                       aircraft are based on fiscal year 2017 O&S data.


Page 170                                                                                  GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The H-60L and H-60M Life Cycle Sustainment Plans provide a roadmap for the sustainment of the aircraft, with
   the UH-60A being covered under the H-60L plan, according to Army officials. The Army manages the UH-60A,
   UH/HH-60L, and UH/HH-60M in an integrated manner, according to program officials.

•   The Army is focused on executing a 100-percent organic core capability for all UH/HH-60 airframes and depot-
    level reparables. The Army performs depot maintenance on the aircraft at Corpus Christi Army Depot, Texas.

•   The Army uses Sikorsky Aircraft Corporation, the Army Supply System, and the Defense Logistics Agency to
    obtain parts for the aircraft. Specifically, the Army uses long-term strategic contracts that are managed by the
    Defense Logistics Agency to procure spare parts for the UH/HH-60.


Availability and Condition
From fiscal year 2011 through fiscal year 2019, the UH/HH-60 missed its mission capable goals. However, the
percent of mission capable aircraft increased from fiscal year 2011 to fiscal year 2019. According to officials, the
UH/HH-60 missed its goals because of spare parts quality issues as well as a reduction of repair programs and late
deliveries of supply items by the vendor. From fiscal year 2011 through fiscal year 2019, the not mission capable
maintenance (NMCM) rate decreased, while the not mission capable supply (NMCS) rate increased. Officials
explained that the increase in the NMCS rate was due, in part, to spare parts quality and availability issues, which
required replacements due to recalls for safety purposes. Specific details on mission capable and not mission
capable rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2017, the UH/HH-60’s overall O&S costs decreased, from about $1.82
billion in fiscal year 2011 to about $1.4 billion in fiscal year 2017. Maintenance accounted for 43 percent of O&S
costs over the period, but overall O&S costs decreased by $494.06 million between fiscal years 2011 and 2017.
According to officials, upgrading the UH-60A aircraft to UH-60M aircraft decreased the overall maintenance costs for
the fleet. Depot-level reparables was the most significant category of maintenance costs, averaging $290.66 million
per year, or 44 percent of total maintenance costs from fiscal years 2011 through 2017. Depot maintenance was the
smallest maintenance cost category, averaging $0.53 million per year, or less than 1 percent of total maintenance
costs for the same time period.




Page 171                                                                         GAO-21-101SP Weapon System Sustainment
UH/HH-60 Total Operating and Support Costs




Note: We obtained fiscal year 2018 operating and support (O&S) cost data from the Army, but we learned from the Army that the data were
inaccurate. Thus, the costs presented here for the Army aircraft are based on fiscal year 2017 O&S data.

From fiscal year 2011 through fiscal year 2017, the UH/HH-60’s O&S costs per aircraft decreased, from about $1.06
million to $0.76 million, while the mission capable rate increased, from 69 percent to 74 percent. Maintenance costs
per aircraft, on average, accounted for about 43 percent of the total O&S costs per aircraft, averaging $0.37 million
per year between fiscal years 2011 and 2017. Additionally, the number of aircraft in the fleet increased, from 1,722
in fiscal year 2011 to 1,911 in fiscal year 2018.




Page 172                                                                                            GAO-21-101SP Weapon System Sustainment
UH/HH-60 Operating and Support Costs per Aircraft and Fleet Size




Note: We obtained fiscal year 2018 operating and support (O&S) cost data from the Army, but we learned from the Army that the data were
inaccurate. Thus, the costs presented here for the Army aircraft are based on fiscal year 2017 O&S data.


Sustainment Challenges and Mitigation Actions
Supply Support: The Army has experienced parts quality challenges that have caused delays in repair and parts
production lead times for the UH/HH-60. To address these challenges, the program office is adjusting lead time
requirements and using more long-term contracts with manufacturers. Additionally, officials stated that they have
worked to mitigate parts issues by leading monthly engagements with parts suppliers to reduce production lead
times. Army officials also stated that they continually work with Sikorsky Aircraft Corporation and the Defense
Logistics Agency to expedite deliveries for parts shortages impacting Corpus Christi Army Depot and commercial
repair output.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 173                                                                                            GAO-21-101SP Weapon System Sustainment
                                     MH-60R Seahawk Sustainment Quick Look
                                     Common Name: MH-60 Romeo
                                     Lead Service: Navy

                                     Background
Program Essentials                   The MH-60R Seahawk is a twin engine helicopter first manufactured in 2005.
Manufacturer: Sikorsky               Its primary missions are anti-submarine warfare, anti-surface warfare, and
                                     electromagnetic warfare. The MH-60R is designed to operate aboard
Sustainment: Depot maintenance       cruisers, destroyers, littoral combat ships, and aircraft carriers. The aircraft is
conducted at Navy Fleet              equipped with a 250-foot cable rescue hoist with a 600-pound lift capability,
Readiness Centers and field          and a cargo hook with a 6,000-pound capacity.
maintenance conducted by Navy
maintainers                          Life Cycle of the MH-60R
Program Office: Program
Manager – Air 299, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 6.76 years
Average lifetime flying hours:       Overview
2,547 hours per aircraft             In fiscal year 2019, the MH-60R fleet did not meet its mission capable goal
Depot maintenance activity           because some of the fleet was not mission capable due to depot,
and squadron locations:              maintenance, and supply issues. In addition, the MH-60R exceeded its
                                     mission capable goals in only two years from fiscal year 2011 through 2019.
                                     Total not mission capable rates increased from fiscal year 2011 to fiscal year
                                     2019 because of low maintenance personnel-to-aircraft ratios, according to
                                     Navy officials. Additionally, operating and support (O&S) costs per aircraft
                                     increased, from about $4.33 million in fiscal year 2011 to about $5.24 million
                                     in fiscal year 2018. According to officials, O&S costs grew during this time
                                     period because the total number of aircraft increased, which required
                                     additional personnel to maintain and support additional fielded aircraft,
                                     squadrons, and sites.

                                     MH-60R Sustainment Status




Sustainment Challenges
and Mitigation Actions
The MH-60R faces maintenance
challenges, as its fleet size grew
rapidly between fiscal years 2011
and 2019. Officials are working to
address these issues.




Page 174                                                                        GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The MH-60R Multi-Mission Helicopter Acquisition Logistics Support Plan (2005) describes the strategy to
   coordinate and manage the logistics elements supporting the sustainment of the program. The plan provides the
   planning data to accomplish life-cycle support for the program and contains logistics information and a
   production planning management tool. Further, the plan is designed to utilize the benefits derived from support
   planning and program accomplishments on other H-60 aircraft in an attempt to eliminate the need for
   redevelopment, re-validation, and re-verification of Navy resources.

•   The Naval Supply Systems Command awarded a performance-based logistics contract in 2015 to primarily
    repair MH-60 depot-level reparables and manage the inventory of those spare parts, with the option for the
    contractor to buy parts if replacements were needed.

•   Depot maintenance occurs at Navy Fleet Readiness Centers, and Navy maintainers sustain and conduct field
    maintenance for the MH-60R. Generally, depot maintenance occurs every 3 years, according to officials.


 Availability and Condition
The MH-60R exceeded its mission capable goals in only two years from fiscal year 2011 through 2019. Also, the
percent of mission capable aircraft decreased each year from fiscal year 2011 to fiscal year 2019. According to
Navy officials, the MH-60R missed its mission capable goals due to low maintenance personnel-to-aircraft ratios,
insufficient skills of and training for maintenance personnel, and a lack of updated technical publications. From fiscal
year 2011 through fiscal year 2019, the not mission capable rates maintenance (NMCM) and supply (NMCS) rates
generally increased. According to Navy officials, the NMCM rate increase was due to a shortage of maintenance
personnel as the number of aircraft increased. Furthermore, in fiscal years 2018 and 2019, the NMCS rate was
increasingly an issue for the aircraft, and officials explained that parts inventories were unable to keep pace with
aircraft deliveries. Specific details on mission capable and not mission capable rates were omitted because the
information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the MH-60R’s total O&S costs tripled, which officials said was
largely due to an increase in the fleet size—from 92 aircraft in fiscal year 2011 to 227 in fiscal year 2018. According
to officials, this increase in the fleet size led to additional personnel requirements to maintain the aircraft and sites.
Maintenance costs accounted for a large share of O&S costs over the period, increasing from about $115.94 million
in fiscal year 2011 to $451.31 million in fiscal year 2018, which officials explained was caused by the increase in the
number of aircraft and flight hours. The largest category of maintenance costs was depot-level reparables, which
increased from about $80.73 million in fiscal year 2011 to $240.3 million in fiscal year 2018. According to officials,
the increase in costs for depot-level reparables was due to an increase in depot inductions as new aircraft entered
their first depot maintenance induction cycles and warranties expired on new production parts.




Page 175                                                                           GAO-21-101SP Weapon System Sustainment
MH-60R Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the MH-60R’s O&S costs per aircraft increased from about $4.33
million in fiscal year 2011 to $5.24 million in fiscal year 2018. Unit level manpower, maintenance, and continuing
system improvement costs increased as the number of aircraft more than doubled, from 92 aircraft in fiscal year
2011 to 262 aircraft in fiscal year 2019. According to officials, this increase in fleet size increased the number of
flying hours, which also led to an increase in fuel costs captured under unit operations costs over this time period.




Page 176                                                                         GAO-21-101SP Weapon System Sustainment
MH-60R Operating and Support Costs per Aircraft Compared and Fleet Size




Sustainment Challenges and Mitigation Actions
Maintenance: According to officials, maintenance of the MH-60R has been challenging due to a lack of adequately
trained maintenance personnel, technical publications, and funding. The officials explained that the number of
aircraft requiring support increased above the primary authorized allowance, and the funding provided for support
equipment and logistics was not increased to support the assigned aircraft. To combat these issues, officials stated
that they are working to adjust priorities to better support the fleet, better communicate requirements for
sustainment, and develop performance plans.

Supply: Officials acknowledged that there was an increased shortage of parts to repair the aircraft in fiscal year
2018. Officials also told us that they are working to be proactive and better position the program to react to any
unforeseen issues with parts wearing out. Specifically, program officials reported that they are planning to better
align the number of aircraft requiring support—which currently exceeds the primary authorized allowance—with the
available resources for sustaining the fleet, to ensure that the fleet is not larger than they have the supply support to
handle.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 177                                                                          GAO-21-101SP Weapon System Sustainment
                                    MH-60S Seahawk Sustainment Quick Look
                                    Common Name: MH-60 Sierra
                                    Lead Service: Navy

                                    Background
Program Essentials                  The MH-60S Seahawk is a twin engine helicopter first manufactured in 2000.
Manufacturer: Sikorsky              Its primary missions are anti-surface warfare, combat search and rescue,
                                    organic airborne mine countermeasure, and combat support missions. The
Sustainment: Depot maintenance      MH-60S is designed to operate aboard cruisers, destroyers, littoral combat
conducted at Navy Fleet             ships, and aircraft carriers. This aircraft, which shares an airframe with the
Readiness Centers and field         MH-60R, is equipped with a 250-foot cable with a 600-pound lift capability,
maintenance conducted by Navy       and a cargo hook with a 6,000-pound capacity.
maintainers
                                    Life Cycle of the MH-60S
Program Office: Program
Manager – Air 299, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 10.93 years
Average lifetime flying hours:
3,889 hours per aircraft            Overview
Depot maintenance activity          In fiscal year 2019, the MH60S fleet did not meet its mission capable rate
and squadron locations:             goal, nor in any other year since fiscal year 2011. The MH-60S did not meet
                                    its goal because of depot, maintenance, and supply issues. Not mission
                                    capable rates increased from fiscal year 2011 to fiscal year 2019 because of
                                    low maintenance personnel-to-aircraft ratios, according to Navy officials.
                                    Additionally, operating and support (O&S) costs per aircraft increased, from
                                    about $4.1 million in fiscal year 2011 to about $5.12 million in fiscal year
                                    2018. According to officials, O&S costs increased largely because of an
                                    increase in the number of total aircraft, which required additional personnel to
                                    maintain and support the additional fielded aircraft, squadrons, and sites.

                                    MH-60S Sustainment Status




Sustainment Challenges
and Mitigation Actions
The MH-60S faces challenges due
to maintenance and supply issues.
Program office officials are
working to adjust priorities to
better support the fleet.




Page 178                                                                     GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The MH-60S Life Cycle Sustainment Plan (2002) describes the strategy to monitor and accomplish MH-60S
   program objectives, program schedules, and assigned program responsibilities. The plan provides the logistics
   considerations, a management tool for program resources, and other planning data to accomplish life-cycle
   support for the program.

•   In 2015, the Naval Supply Systems Command awarded a performance-based logistics contract to repair MH-60
    depot-level reparables and manage the inventory of those spare parts, with the option for the contractor to buy
    parts if replacements were needed.

•   Depot maintenance occurs at Navy Fleet Readiness Centers and Navy maintainers sustain and conduct field
    maintenance for the MH-60S. Generally, depot maintenance occurs every 3 years, according to officials.


 Availability and Condition
The MH-60S missed its mission capable goals from fiscal year 2011 through fiscal year 2019. Also, the percent of
mission capable aircraft decreased. According to Navy officials, the MH-60S missed its mission capable goals due
to low maintenance personnel-to-aircraft ratios, insufficient skills of and training for maintenance personnel, and a
lack of supporting products, to include technical publications. From fiscal year 2011 through fiscal year 2019, the
rates generally increased for not mission capable maintenance (NMCM) and not mission capable supply (NMCS).
According to Navy officials, the NMCM rate increased due to a lack of maintenance personnel as the number of
aircraft increased. Furthermore, in fiscal years 2018 and 2019 NMCS was increasingly an issue for the aircraft, as
the spares posture was unable to support fielding aircraft, according to officials. Specific details on mission capable
and not mission capable rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the MH-60S’s total O&S costs rose by about 57 percent, which
officials told us was largely due to an increase in fleet size—from 181 aircraft in fiscal year 2011 to 228 in fiscal year
2018. According to officials, this increase in fleet size led to additional personnel requirements to maintain the
aircraft and sites. Maintenance costs accounted for a large share of O&S costs over the period, increasing from
about $208.7 million in fiscal year 2011 to $456.59 million in fiscal year 2018, which officials attributed to the
increase in the number of aircraft and flight hours. The most significant category of maintenance costs was depot-
level reparables, which increased from about $99.57 million in fiscal year 2011 to $209.68 million in fiscal year 2018.
According to officials, the increase in costs for depot-level reparables was due to an increase in depot inductions as
new aircraft entered their first depot maintenance induction cycles.




Page 179                                                                          GAO-21-101SP Weapon System Sustainment
MH-60S Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the MH-60S’s O&S costs per aircraft increased from about $4.1
million in fiscal year 2011 to $5.12 million in fiscal year 2018. This occurred due to increases in costs as the number
of aircraft increased by about 26 percent, from 181 aircraft in fiscal year 2011 to 228 aircraft in fiscal year 2018.
According to officials, this increase in fleet size increased the number of flying hours, which also led to an increase
in fuel costs captured under unit operations costs over this time.




Page 180                                                                         GAO-21-101SP Weapon System Sustainment
MH-60S Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Maintenance: Maintenance of the MH-60S has been challenging due to a lack of adequately trained maintenance
personnel, technical publications, and funding. According to officials, while the number of aircraft requiring support
increased above the primary authorized allowance at squadrons, the funding provided for support equipment and
logistics was not increased to support the assigned aircraft. To combat these issues, officials are working to adjust
priorities to better support the fleet, better communicate requirements for sustainment, and develop performance
plans.

Supply: Officials acknowledged that there was an increased shortage of parts to repair the aircraft in fiscal year
2018. Officials also told us that they are working to better position the program to react to any unforeseen issues
with parts wearing out. Specifically, program officials reported that they are planning to better align the number of
aircraft requiring support—which is currently over the primary authorized allowance—with the available resources
for sustaining the fleet, to ensure that the fleet is not larger than they have the supply support to handle.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 181                                                                         GAO-21-101SP Weapon System Sustainment
                                      AH-1Z Viper Sustainment Quick Look
                                      Common Name: AH-1Z
                                      Lead Service: Marine Corps

                                      Background
Program Essentials                    The AH-1Z Viper is a close air support, armed escort reconnaissance, anti-
Manufacturer: Bell Helicopter         armor operations, and anti-air warfare aircraft first manufactured in 2006. It is
Textron Inc.                          designed with a four-bladed composite rotor system, four-bladed tail rotor,
                                      and a fully integrated glass cockpit. The aircraft is equipped with an
Sustainment: Depot maintenance        integrated advanced fire control system and the capacity to support multiple
conducted at Navy Fleet               weapon configurations.
Readiness Centers, Bell, and
Tobyhanna Army Depot; and field       Life Cycle of the AH-1Z
maintenance conducted by Marine
Corps maintainers
Program Office: Program
Manager – Air 276, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 4.4 years
                                      Overview
                                      From fiscal year 2011 through fiscal year 2019, the AH-1Z fleet did not meet
Average lifetime flying hours:        its mission capable rate goal. Specifically, in fiscal year 2019, the AH-1Z did
946 hours per aircraft                not meet its goal because of depot, maintenance, and supply issues. Not
Depot maintenance activity            mission capable rates due to depot, maintenance, and supply issues
and squadron locations:               increased from fiscal year 2011 to fiscal year 2019 because squadrons did
                                      not have enough maintainers or spare parts to support more aircraft than
                                      what was authorized to perform their mission, according to officials.
                                      Additionally, total operating and support (O&S) costs per aircraft increased,
                                      from about $2.68 million in fiscal year 2011 to about $3.36 million in fiscal
                                      year 2018. According to officials, O&S costs per aircraft increased as a result
                                      of the upgrade from the older AH-1W aircraft to the newer AH-1Z aircraft.

                                      AH-1Z Sustainment Status




Sustainment Challenges
and Mitigation Actions
The AH-1Z is experiencing
maintenance and supply
challenges. The Marine Corps’
mitigation actions include reducing
unscheduled maintenance,
reducing the number of aircraft,
and improving supply chains.



Page 182                                                                        GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The Life-Cycle Sustainment Plan (2016) provides the overall framework for the sustainment of the AH-1Z
   throughout its life cycle. This plan documents the program’s integrated product support plan and total life-cycle
   support management strategy.

•   The Marine Light Helicopter Independent Readiness Review (2017) provides an in-depth look into AH-1Z
    sustainment issues and identifies actionable recommendations to mitigate challenges.

•   Marine Corps field maintainers maintain the AH-1Z at the squadron level. The Navy Fleet Readiness Centers
    conduct depot maintenance under a planned interval of 54 months. Naval Supply Systems Command and the
    Defense Logistics Agency provide supply chain management.

•   The Naval Supply Systems Command entered into a performance-based logistics contract with Bell Helicopter
    Textron beginning in fiscal year 2020 to provide timely, cost-effective repairs as well as supply support.


Availability and Condition
From fiscal year 2011 through fiscal year 2019, the AH-1Z missed its mission capable goals. Also, the percent of
mission capable aircraft decreased during this time period. From fiscal year 2011 through fiscal year 2018, the not
mission capable maintenance (NMCM) rate increased and the not mission capable supply (NMCS) rate decreased.
Officials stated that the increase in the NMCM rate between fiscal years 2011 and 2018 was due to a high rate of
unscheduled maintenance, inadequate maintainer training and not enough maintainers, and other poor maintenance
practices—such as insufficient preventive maintenance and corrosion control—that sacrifice long-term sustainment
in order to meet flight schedules. Specific details on mission capable and not mission capable rates were omitted
because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the AH-1Z’s total O&S costs increased. According to officials, O&S
costs increased because the AH-1Z inventory went up from 16 aircraft in fiscal year 2011 to 95 aircraft in fiscal year
2018 as squadrons transitioned from the older predecessor aircraft to the newer AH-1Z and maintainers were
trained on the new system. Unit level manpower and maintenance costs accounted for the largest shares of O&S
costs over the period. Unit level manpower costs increased from about $22.82 million in fiscal year 2011 to about
$99.87 million in fiscal year 2018, whereas maintenance costs increased from about $8.37 million to about $101.88
million. In fiscal year 2018, depot-level reparables was the largest category of maintenance costs at about $40.79
million, while depot maintenance was the smallest category of maintenance costs at $5.61 million. Officials stated
that depot-maintenance costs were low because the AH-1Z fleet was in the early stages of being fielded and the
aircraft has only recently begun to enter depot maintenance.




Page 183                                                                        GAO-21-101SP Weapon System Sustainment
AH-1Z Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the AH-1Z’s O&S costs per aircraft generally increased from fiscal
year 2011 through fiscal year 2014 and generally decreased from fiscal year 2015 through fiscal year 2018, while
the mission capable rate decreased. Also, maintenance costs per aircraft, on average, accounted for one-third of
total cost per aircraft, averaging about $1.07 million per year. According to officials, that is a result of an increase in
the number of depot reparable demands and an increase in component costs. Additionally, as noted previously, the
AH-1Z fleet increased by 79 aircraft, from 16 aircraft in fiscal year 2011 to 95 aircraft in fiscal year 2018.




Page 184                                                                            GAO-21-101SP Weapon System Sustainment
AH-1Z Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Maintenance: The AH-1Z faces maintenance challenges related to a high rate of unscheduled maintenance and an
inability to fully support current aircraft numbers at the squadron level. As a result, officials stated that unscheduled
maintenance is driving the maintenance planning, instead of the maintenance plans driving the maintenance
workload. This reactive maintenance disrupts the scheduled maintenance plan and leaves only work hours available
to complete the bare minimum maintenance to keep the aircraft flyable while deferring more in-depth maintenance
work to later, according to officials. To mitigate this situation, officials told us that they are updating long-term
maintenance processes, which include—but are not limited to—technical publication updates, an analysis of
maintenance levels, improving maintainer technical knowledge, and the establishment of a corrosion prevention
program. Further, the program office has established fleet support team site offices at each major H-1 location to
assist the fleet with maintenance and troubleshooting discrepancies.

Supply Support: The AH-1Z has experienced supply challenges, which officials are working to mitigate in several
ways. For example, program office officials told us that the number of aircraft at the standard squadron is
approximately 25 percent above the normal authorized allowance for which squadrons are staffed and equipped. As
a result, squadrons are unable to support the AH-1Z. To mitigate this issue, officials told us they are working to
adjust the fleet size to ensure that the squadrons do not have any overages they cannot support, and have
implemented the Light Attack Aircraft Management Plan to perform short- and long-term preservation to excess
inventory, thereby reducing workload to the fleet and burdens to the supply system. Further, the officials stated that,
to alleviate supply chain delays, the Navy Supply Systems Command entered into a performance-based logistics
contract with Bell in December 2019 for rotors and drives components and the Defense Logistics Agency is planning
to enter into a performance-based contract with Bell in late fiscal year 2020 for about 3,600 consumable items.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 185                                                                          GAO-21-101SP Weapon System Sustainment
                                     CH-53E Sustainment Quick Look
                                     Common Name: Super Stallion
                                     Lead Service: Marine Corps

                                     Background
Program Essentials                   The CH-53E Super Stallion helicopter, which transports heavy equipment
Manufacturer: Sikorsky               and supplies for amphibious assault, was first manufactured in 1978. The
                                     aircraft incorporates secure communications capability, a global positioning
Sustainment: Field maintenance       system, aviator night vision imaging systems heads up display sensors, and
conducted by USMC maintainers        it carries three 50-caliber guns to support combat and rescue missions.
and depot maintenance conducted
at Navy Fleet Readiness Centers      Life Cycle of the CH-53E
and Korean Air Co., Ltd
Program Office: Program
Manager – Air 261, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 31.8 years
                                     Overview
Average lifetime flying hours:       In year 2019, the CH-53E fleet did not meet its mission capable goal. The
6,363.48 hours per aircraft          CH-53E did not meet its goal due to maintenance and supply issues. In
Depot maintenance activity           addition, from fiscal year 2011 to fiscal year 2019, the CH-53E did not meet
and squadron locations:              its mission capable goal and not mission capable rates increased from fiscal
                                     year 2011 to fiscal year 2019. According to officials, this decrease in mission
                                     capability was due to aging issues, including ineffective depot maintenance,
                                     aircraft not properly reset to full mission capability following combat, poor
                                     supply support and obsolescence, and decreased maintenance efficiency.
                                     Additionally, operating and support (O&S) costs per aircraft increased from
                                     $6.74 million in fiscal year 2011 to $7.39 million in fiscal year 2018.
                                     Maintenance costs were the largest contributor to O&S costs, at 58 percent
                                     per year on average. Depot-level reparables was the largest category of
                                     maintenance costs for the CH-53E, which made up 50 percent of total
                                     maintenance costs, on average.

                                     CH-53E Sustainment Status




Sustainment Challenges
and Mitigation Actions
The CH-53E is an aging aircraft
with maintenance and supply
challenges. Actions to mitigate
these challenges include resetting
the fleet, revising the integrated
maintenance program, and
improving the supply chain.




Page 186                                                                      GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The Life-Cycle Sustainment Plan (2016) documents the program’s integrated product support plan and total life-
   cycle support management strategy and provides a roadmap toward achieving performance requirements and
   minimizing the life-cycle cost associated with acquisition and sustainment through transition to the CH-53K.

•   Supply support is provided by the Naval Supply Systems Command and the Defense Logistics Agency.
    According to program office officials, the Naval Supply Systems Command entered into a performance-based
    logistics contract with Sikorsky Aircraft Corporation in 2005 for repair support of 10 components and was
    expanded later for an additional 54 components.

•   According to officials, the CH-53E is maintained organically by Marine Corps maintainers and at Navy Fleet
    Readiness Centers and Korean Air Co., Ltd., under a depot planned maintenance interval (PMI) cycle. The PMI
    event takes 7 months to complete and occurs every 900 to 1,600 flight hours.


 Availability and Condition
From fiscal year 2011 through fiscal year 2019, the CH-53E program missed its mission capable goal and the
mission capable rate decreased from fiscal year 2011 to fiscal year 2019. The percent of mission capable aircraft
decreased largely due to maintenance issues and reporting metrics changes, according to officials.

From fiscal year 2011 through fiscal year 2019, the not mission capable maintenance (NMCM), depot (NMCD), and
supply (NMCS) rates increased. According to officials, the increases in the NMCM and NMCS rates were due to
insufficient numbers of squadron maintenance personnel, whose effectiveness was hindered by a lack of required
support equipment, inadequate technical support, and an overall lack of formal and on-the-job, follow-on training.
Further, persistent critical parts shortages added to maintenance and supply delays. Officials stated that these parts
shortages were a result of obsolescence issues and of relying on historical demand patterns instead of utilizing
predictive demand to improve readiness. According to officials, a 2017 change in metrics calculations caused the
increase in the NMCD rate and therefore shifted the mission capable rate downward, and a change to data business
rules in 2018 caused a decrease in the NMCM rate and an increase in the NMCS rate. Specific details on mission
capable and not mission capable rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
The CH-53E’s total O&S costs remained fairly steady from fiscal year 2011 through fiscal year 2018, averaging
around $1 billion per year. Maintenance costs accounted for the largest share of O&S costs over the period,
averaging about $613.29 million per year, or 61 percent of the total. Depot-level reparables was the most significant
maintenance cost category, averaging $307.49 million per year.




Page 187                                                                        GAO-21-101SP Weapon System Sustainment
CH-53E Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the CH-53E’s O&S costs per aircraft increased from $6.74 million to
$7.39 million, while the mission capable rate decreased. Also, maintenance costs per aircraft, on average,
accounted for more than half of total O&S costs per aircraft, averaging about $4.2 million per year. Additionally, the
number of aircraft decreased, from 151 in fiscal year 2011 to 141 in fiscal year 2018, due to a lack of available
aircraft, as the back-up aircraft inventory was previously exhausted.




Page 188                                                                        GAO-21-101SP Weapon System Sustainment
CH-53E Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: The CH-53E has been in operation for close to 40 years, with the mission capable rate declining from fiscal
year 2011 through fiscal year 2019 due to challenges associated with an aging platform, according to officials.
Sikorsky conducted a service-life extension study in the mid-1990s and determined that replacing the bulkhead—a
dividing wall or barrier between compartments—would extend the service life of the CH-53E from 6,000 to 10,000
hours. As a result, Marine Corps aviation funded all bulkhead replacements. Despite the higher-than-average
utilization rates for aircraft deployed in support of the wars in Iraq and Afghanistan, a plan rotating aircraft to reduce
the number of flying hours has ensured that only three aircraft should reach the end of their service lives prior to
2024, which is the first year that CH-53Es will be retired.

Maintenance: According to a 2015 Marine Corps readiness review, many of the CH-53E’s readiness issues are due
to very heavy and hard usage in 11 years of wartime, along with a lack of needed depot maintenance to restore the
aircraft upon their return. Additionally, there is a shortage of squadron maintenance personnel, and their
effectiveness is hindered by a lack of required support equipment, inadequate technical support, an insufficient
quantity of specially trained and qualified squadron personnel, and an overall lack of formal and on-the-job, follow-
on training. Lastly, there is a high number of aircraft in maintenance outside of squadrons, which is one of the
leading causes of the reduced number of aircraft available to operational commanders. The Marine Corps’ ongoing
and planned actions include resetting the CH-53E fleet to full mission capability beginning in 2016, directing
renewed focus on training to increase technical expertise of aircraft maintainers, changing the CH-53E depot
planned maintenance interval (PMI) from a calendar to a flight hour requirement in 2017, and implementing a depot
readiness initiative in 2018 to quickly return post-PMI aircraft to a mission capable status.

Supply Support: The CH-53E is experiencing shortages of parts due to diminishing manufacturing sources,
obsolescence issues, and over-reliance on demand history to drive supply support decisions instead of using more
forward-looking, predictive criteria that make a difference in readiness. As a result, the program office has ongoing
and planned actions to improve supply chain performance by expanding the use of product support arrangements
and performance-based logistics contracts with industry partners and by implementing demand planning and
predictive forecasting tools to determine parts inventory requirements.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.
Page 189                                                                           GAO-21-101SP Weapon System Sustainment
                                    MV-22B Osprey Joint Advanced Vertical Lift
                                    Aircraft Sustainment Quick Look
                                    Common Name: MV-22B Osprey
                                    Lead Service: Marine Corps

Program Essentials                  Background
Manufacturer: Bell-Boeing Joint     The MV-22B Osprey Joint Advanced Vertical Lift was the first tilt rotor
Program Office                      aircraft, having been first manufactured in 1996. The aircraft operates as a
Sustainment: Depot maintenance      helicopter when taking off and landing vertically, and it has the long-range
conducted at Navy Fleet             cruise capabilities of a twin turboprop aircraft. The aircraft transports troops,
Readiness Centers, Marine Corps     equipment, and supplies, and it operates from ships or expeditionary airfields
Air Station – Hawaii, and Army      ashore.
Center – Huntsville, Alabama; and
field maintenance conducted by      Life Cycle of the MV-22
Marine Corps, Navy, and
contractor maintainers
Program Office: V-22 Joint
Program Office – Air 275, Naval
Air Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data               Overview
Average age: 8 years
                                    In fiscal year 2019, the MV-22B fleet did not meet its mission capable goal
Average lifetime flying hours:      due to depot, maintenance, and supply issues. Further, the MV-22B fleet did
1,400 per aircraft                  not meet its mission capable goal in any year from fiscal year 2011 to fiscal
                                    year 2019. According to officials, unavailability due to depot, maintenance,
Depot maintenance activity          and supply issues increased from in fiscal year 2011 to fiscal year 2019
and squadron locations:             because of issues with corrosion, engineering delays, and supply shortages.
                                    Additionally, operating and support (O&S) costs per aircraft decreased
                                    slightly, from about $6.58 million in fiscal year 2011 to about $6.04 million in
                                    fiscal year 2018. According to officials, costs per aircraft decreased as more
                                    aircraft were introduced into the fleet.

                                    MV-22B Sustainment Status




Sustainment Challenges
and Mitigation Actions
The MV-22B is experiencing
aging, maintenance, and supply
challenges. The Marine Corps’
mitigation actions include
corrosion repair, preventing
aircraft deterioration, and
improving supply chains.

Page 190                                                                      GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The Life-Cycle Sustainment Plan (2014) provides the overall framework for the sustainment of the MV-22B
   system throughout its life cycle. This plan documents the program’s integrated product support plan and total
   life-cycle support management strategy.

•   The Joint Program Office manages the MV-22B for the Marine Corps, the CV-22 Osprey for the Air Force and
    United States Special Operations Command, and the CMV-22 for the Navy, as they are similar systems. Bell-
    Boeing provides a portion of product support, such as on-site fleet support, in-service engineering support, and
    access to parts, among other things, through a performance-based logistics contract managed by the Joint
    Program Office.

•   Marine Corps field maintainers maintain the MV-22B at the squadron level. The Navy Fleet Readiness Centers
    conduct depot maintenance under a planned interval of every 24 months. Naval Supply Systems Command and
    Defense Logistics Agency provide supply support.


Availability and Condition
From fiscal year 2011 through fiscal year 2019, the MV-22B missed its mission capable goals and the percent of
mission capable aircraft decreased from fiscal year 2011 to fiscal year 2019. According to officials, the MV-22B is
missing its annual goals because of corrosion issues, materiel unavailability, and issues caused by technical data
gaps and engineering delays.

From fiscal year 2011 through fiscal year 2019, the rates generally increased for not mission capable depot
(NMCD), not mission capable maintenance (NMCM), and not mission capable supply (NMCS). According to
officials, a November 2018 update to the approach to calculating the mission capability data for this aircraft resulted
in this decrease in the NMCM rate and increase in the NMCS rate. Specific details on mission capable and not
mission capable rates were omitted because the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the MV-22B’s total O&S costs more than doubled, as the number of
aircraft increased from 124 to 284. Additionally, in 2017 the Navy implemented a new aircraft retrofitting program
that modifies the aircraft’s configuration to address reliability or safety concerns. This program resulted in increased
costs in the continuing system improvements category, specifically in fiscal year 2018. Joint Program Office officials
noted that this reconfiguration does not result in immediate improvements to reliability, but is expected to help in the
future. Maintenance costs increased each year and accounted for 50 percent of the total O&S costs from fiscal
years 2011 through 2018, averaging about $568 million per year. Depot-level reparables was the most significant
category of maintenance costs, averaging $231 million per year during the same time period.




Page 191                                                                          GAO-21-101SP Weapon System Sustainment
MV-22B Total Operating and Support Costs




The MV-22B’s total O&S costs per aircraft decreased steadily from fiscal year 2011 through fiscal year 2016 before
increasing in fiscal years 2017 and 2018. Specifically, O&S costs per aircraft increased from $4.54 million in fiscal
year 2016 to $6.04 million in fiscal year 2018, while the mission capable rate decreased. According to officials, this
increase is a result of additional demand for aircraft propeller blades in fiscal years 2017 and 2018, which had
increased in price by 209 percent. Maintenance costs per aircraft, on average, accounted for about half of the total
costs per aircraft, averaging about $2.7 million per year from fiscal years 2011 through 2018. Additionally, the
number of aircraft more than doubled, from 124 aircraft in fiscal year 2011 to 284 aircraft in fiscal year 2018, with a
planned fleet size of 360 MV-22Bs by fiscal year 2024.




Page 192                                                                         GAO-21-101SP Weapon System Sustainment
MV-22B Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: As the MV-22B ages and more aircraft undergo depot-level maintenance, officials are finding more evidence
of corrosion. Officials told us that they have developed a corrosion roadmap that allows them to discover where
corrosion is present, and that they have involved original equipment manufacturing partners in finding and repairing
corroded parts. As a result, the Joint Program Office released about 12 technical directives to repair and prevent
corrosion. According to Joint Program Office officials, the benefits of these improvements are starting to reduce the
rate of corrosion-related failures and removals. Further, according to officials, they are currently working on
developing additional repairs so that the entire fleet is not affected by these corrosion issues.

Maintenance: An independent review of the Osprey program found that the MV-22B currently has too many
configurations—over 70 in total—for the Joint Program Office to maintain adequately and consistently. To mitigate
this issue, the Joint Program Office plans to reduce the number of configurations and ultimately achieve a common
configuration, which officials hope will result in less time spent on unplanned maintenance and inspections. The first
aircraft to undergo reconfiguration will be completed in fiscal year 2020. The MV-22B also faces maintenance issues
related to technical data gaps. For example, according to officials, non-standard, complex repairs require temporary
engineering instructions. To mitigate this situation, officials told us that they had developed an engineering hotline
and held daily engineering phone calls to reduce the amount of time it takes them to address maintenance issues,
review outstanding engineering requests, and discuss next steps. According to Joint Program Office officials, this
has resulted in a reduction of average turnaround time by approximately 50 percent for temporary engineering
instructions, thereby reducing data gaps. The Joint Program Office officials also stated that they are addressing the
technical data gaps by delivering 170 Structural Repair Manuals over the next 5 years to reduce fleet demand and
improve repair turnaround time. The joint program office has also begun an aircraft preservation program to help
reduce the number of aircraft deemed not mission capable due to maintenance. For example, according to officials,
when MV-22B aircraft are not in use, they will be preserved in a mission capable state until needed, thereby
reducing the amount of damage caused by environmental factors such as humidity and reducing the amount of time
to fix any issues. Lastly, the Joint Program Office stated that it has awarded a Performance Based Logistics and
Engineering (PBL&E) contract that directly incentivizes industry to align with fleet goals of reducing the number of
“long-term down” aircraft and reduce NMCM rates. According to the Joint Program Office, the PBL&E contract also
incentivizes rapid engineering responses, which should improve mission capable rates by reducing time spent
awaiting maintenance, eliminating technical data gaps, and informing root cause and corrective actions. According
to the Joint Program Office, these efforts resulted in the number of MV-22B “long-term down” aircraft being reduced
from 66 to 33 in 2019.

Page 193                                                                        GAO-21-101SP Weapon System Sustainment
Supply Support: The MV-22B has experienced spare parts availability issues, which officials are working to
mitigate in several ways. For example, Joint Program Office officials told us that they designed a semi-annual
program with Navy Supply Systems Command to discuss problem components and try to resolve the major issues.
The Joint Program Office also reported pursuing initiatives such as working with Navy Supply Systems Command
and the Defense Logistics Agency to award contracts incentivizing materiel availability. For example, according to
Joint Program officials, they plan to implement a performance-based contract with Bell-Boeing in 2019 to incentivize
meeting-expedited delivery times. In addition, officials reported that the Defense Logistics Agency has initiatives
underway to rectify incorrect part identification numbers so that the correct parts are ordered at the correct rate.


 Program Office Comments
In commenting on a draft of this assessment, the Joint Program Office stated that its efforts initiated in fiscal years
2018 and 2019 to accelerate readiness recovery produced results in fiscal year 2019 and will continue to improve
readiness. Specifically, the Joint Program Office stated that the MV-22B in fiscal year 2019 was able to increase its
flight hours over fiscal year 2018 and meet the fiscal year 2019 flight hour goal. The Joint Program Office noted that
the improvements it has made should continue to result in improved MV-22B readiness rates in the years to come.




Page 194                                                                         GAO-21-101SP Weapon System Sustainment
                                      UH-1Y Venom Sustainment Quick Look
                                      Common Name: UH-1Y
                                      Lead Service: Marine Corps

                                      Background
Program Essentials                    The UH-1Y Venom is a combat assault support, airborne command and
Manufacturer: Bell Helicopter         control, search and rescue, and special operations support rotary aircraft first
Textron Inc.                          manufactured in 2006. It is designed with a four-bladed composite rotor
                                      system and integrated digital cockpit, and it provides heavy load carrying
Sustainment: Depot maintenance        ability.
conducted at Navy Fleet
Readiness Centers, Bell, and          Life Cycle of the UH-1Y
Tobyhanna Army Depot; and field
maintenance conducted by Marine
Corps maintainers
Program Office: Program
Manager – Air 276, Naval Air
Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data                 Overview
Average age: 6.9 years                The UH-1Y did not meet its mission capable goal in any year from fiscal year
                                      2011 to fiscal year 2019. Specifically, in fiscal year 2019, the UH-1Y fleet did
Average lifetime flying hours:        not meet its mission capable goal due to depot, maintenance, and supply
1,389 hours per aircraft              issues. Unavailability due to depot, maintenance, and supply issues
Depot maintenance activity            increased from fiscal year 2011 fiscal year 2019 because, according to
and squadron locations:               officials, squadrons are not manned or equipped with spare parts to support
                                      the inventory of aircraft. Additionally, operating and support (O&S) costs per
                                      aircraft generally remained steady, with an increase from about $3.18 million
                                      in fiscal year 2011 to $3.32 million in fiscal year 2018. According to officials,
                                      the increase was due to the costs associated with the upgrade from the older
                                      UH-1N aircraft to the newer UH-1Y aircraft, which was completed in 2018.

                                      UH-1Y Sustainment Status




 Sustainment Challenges
 and Mitigation Actions
The UH-1Y is experiencing
maintenance and supply
challenges. The Marine Corps’
mitigation actions include reducing
unscheduled maintenance,
reducing the fleet size, and
improving supply chains.



Page 195                                                                        GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The H-1 – Acquisition Category 1C Life-Cycle Sustainment Plan (2016) provides the overall framework for the
   sustainment of the UH-1Y throughout its life cycle. This plan documents the program’s integrated product
   support plan and total life-cycle support management strategy.

•   The Marine Light Helicopter Independent Readiness Review (2017) describes UH-1Y readiness and
    sustainment issues and identifies recommendations to mitigate challenges.

•   Marine Corps field maintainers maintain the UH-1Y at the squadron level. The Navy Fleet Readiness Center -
    East conducts depot maintenance under a planned interval of 54 months. Naval Supply Systems Command and
    Defense Logistics Agency provide supply chain management.

•   The Naval Supply Systems Command entered into a performance-based logistics contract with Bell Helicopter
    Textron beginning in fiscal year 2020 to provide timely, cost-effective repairs as well as supply support.


 Availability and Condition
From fiscal years 2011 through 2019, the UH-1Y generally experienced a decreasing mission capable rate and did
not meet its mission capable goal in any year during this time period. According to officials, the UH-1Y is missing its
goals because there are too many aircraft—approximately 25 percent more than the normally authorized
allowance—that need to be maintained when compared to the amount of maintainers and supply support, which
leads to fewer mission capable aircraft.

From fiscal year 2011 through fiscal year 2018, the not mission capable maintenance (NMCM) rate increased and
the not mission capable supply (NMCS) rate decreased. Officials stated that the increase in the NMCM rate
between fiscal years 2011 and 2018 was due to a high rate of unscheduled maintenance, inadequate maintainer
training and not enough maintainers, and other poor maintenance practices—such as insufficient preventive
maintenance and corrosion control—that sacrifice long-term sustainment for meeting flight schedules. Specific
details on mission capable and not mission capable rates were omitted because the information was deemed by
DOD to be sensitive.

Operating and Support Costs
For fiscal years 2011 through 2018, the UH-1Y’s total O&S costs increased as the mission capable rate decreased.
According to officials, O&S costs increased because the UH-1Y inventory went up from 46 aircraft in fiscal year
2011 to 142 aircraft in fiscal year 2018 as squadrons transitioned from the older UH-1N aircraft to the newer UH-1Y
aircraft—which began in 2007 and concluded in 2017— and maintainers were trained on the new system.
Maintenance costs, which increased from about $38.94 million in fiscal year 2011 to about $214.64 million in fiscal
year 2018, accounted for the largest share of O&S costs over the period. Depot-level reparables was the most
significant category of maintenance costs, at about $108.77 million in fiscal year 2018. Depot-level reparable costs
were higher at the end of the time period due to an increasing number of repair demands and an increase in the
cost of parts, according to program officials.




Page 196                                                                         GAO-21-101SP Weapon System Sustainment
UH-1Y Total Operating and Support Costs




From fiscal year 2011 through fiscal year 2018, the UH-1Y’sO&S costs per aircraft remained steady, averaging
about $3.25 million per year, while the mission capable rate decreased. Also, maintenance costs per aircraft, on
average, accounted for more than one-third of total O&S costs per aircraft, averaging about $1.21 million per year.
According to officials, this was a result of increase in the number of depot reparable demands and an increase in the
cost of parts. Additionally, as noted previously, the UH-1Y fleet increased by 96 aircraft, from 46 aircraft in fiscal
year 2011 to 142 aircraft in fiscal year 2018.




Page 197                                                                        GAO-21-101SP Weapon System Sustainment
UH-1Y Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Maintenance: The UH-1Y faces maintenance challenges related to a high rate of unscheduled maintenance and an
inability to fully support current aircraft numbers at the squadron level. As a result, officials stated that unscheduled
maintenance is driving the maintenance planning instead of the maintenance plans driving the maintenance
workload. This reactive maintenance disrupts the scheduled maintenance plan and only leaves work hours available
to complete the bare minimum maintenance to keep the aircraft flyable while deferring more in-depth maintenance
work to later, according to officials. To mitigate this situation, officials told us that they are updating long-term
maintenance processes, which include—but are not limited to—technical publication updates, an analysis of
maintenance levels, improving maintainer technical knowledge, and the establishment of a corrosion prevention
program. Further, the program office has established fleet support team site offices at each major H-1 location to
assist the fleet with maintenance and troubleshooting discrepancies.

Supply Support: While NMCS rates decreased between fiscal year 2011 and 2018, the UH-1Y has experienced
supply issues, which officials are working to mitigate in several ways. For example, program office officials told us
that the number of aircraft at the standard squadron is approximately 25 percent above the normal authorized
allowance—which is the number for which supplies are purchased; therefore, squadrons are unable to provide
support for the excess aircraft. To mitigate this issue, officials told us they are working to adjust the fleet size by
rotating the aircraft in and out of the fleet on a periodic basis to ensure that the squadrons do not have any overages
they cannot support, and they have implemented the Light Attack Aircraft Management Plan to perform short- and
long-term preservation to excess inventory, reducing workload to the fleet and burdens to the supply system.
Further, to alleviate supply chain delays, the officials stated that the Navy Supply Systems Command entered into a
performance-based logistics contract with Bell in December 2019 for rotors and drives components and the Defense
Logistics Agency is planning to enter into a performance-based contract with Bell in late fiscal year 2020 for about
3,600 consumable items.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 198                                                                          GAO-21-101SP Weapon System Sustainment
                                      CV-22 Osprey Joint Advanced Vertical Lift Aircraft
                                      Sustainment Quick Look
                                      Common Name: CV-22
                                      Lead Service: Air Force

Program Essentials                    Background
Manufacturer: Bell-Boeing Joint       The CV-22 Osprey is a tiltrotor aircraft that was first manufactured as the
Program Office                        Special Operation Forces variant of Marine Corps’ MV-22B Osprey in 2005.
Sustainment: Depot maintenance        The aircraft takes off vertically and, once airborne, the engine and prop rotors
conducted at Navy Fleet               can rotate into a forward position. The CV-22 enables Air Force Special
Readiness Centers – East and          Operations Command aircrews to conduct long-range infiltration, exfiltration,
Southwest and field maintenance       and resupply missions at low altitudes.
conducted by service maintainers
                                      Life Cycle of the CV-22
Program Office: V-22 Joint
Program Office – Air 275, Naval
Air Systems Command, Patuxent
River, Maryland
Fiscal Year 2019 Data
Average age: 7.9 years
Average lifetime flying hours:        Overview
1,860 hours per aircraft
                                      From fiscal years 2013 to 2019, the CV-22 fleet did not meet its aircraft
Depot maintenance activity            availability or mission capable rate goals. In fiscal year 2019, the CV-22 fleet
and squadron locations:               did not meet its goals due to maintenance and supply issues. Maintenance
                                      and supply issues were related to scheduled and unscheduled depot work,
                                      component unreliability, and increased inspection times, according to
                                      officials. Additionally, operating and support (O&S) costs per aircraft
                                      decreased from about $25.6 million in fiscal year 2011 to about $17.7 million
                                      in fiscal year 2018. According to officials, these costs decreased due to an
                                      increase in the size of the fleet from 18 to 50 aircraft.

                                      CV-22 Sustainment Status




 Sustainment Challenges
 and Mitigation Actions
The CV-22 is experiencing
maintenance and supply
challenges. The Air Force’s
mitigation actions include
purchasing retiring parts,
establishing a common
configuration for all CV-22 models,
and improving supply chains.



Page 199                                                                        GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The V-22 Joint Program Life-Cycle Sustainment Plan (2014) provides the overall framework for the sustainment
   of the CV-22 system throughout its life cycle. This plan documents the program’s integrated product support
   plan and total life cycle support management strategy.

•   The Joint Program Office manages the MV-22B for the Marine Corps, the CV-22 Osprey for the Air Force and
    United States Special Operations Command, and the CMV-22 for the Navy as they are similar systems. Bell-
    Boeing provides a portion of product support, such as on-site fleet support, in-service engineering support, and
    access to parts, among other things, through a performance-based logistics contract managed by the Joint
    Program Office.

•   Air Force field maintainers maintain the CV-22 at the organizational and intermediate levels of maintenance. The
    Navy Fleet Readiness Centers conduct depot maintenance under a utilization-based maintenance induction
    schedule; aircraft are inducted for planned depot maintenance at approximately 1,680 flight hours. Naval Supply
    Systems Command and the Defense Logistics Agency provide supply support.


 Availability and Condition
From fiscal year 2013 through fiscal year 2019, the CV-22 failed to meet its aircraft availability and mission capable
rate goals. According to officials, the CV-22 missed its goals because of scheduled and unscheduled depot work,
unreliability of wiring and components, and the length of time to conduct phase inspections. Additionally, over time
the aircraft availability and mission capable goals slightly decreased due to a decrease in requirements, according to
officials.

From fiscal year 2011 through fiscal year 2019, the rates increased for not mission capable maintenance (NMCM)
and not mission capable both (NMCB) maintenance and supply, while the not mission capable supply (NMCS) rate
generally stayed constant. Specific details on mission capable and not mission capable rates were omitted because
the information was deemed by DOD to be sensitive.


 Operating and Support Costs
From fiscal year 2011 through fiscal year 2018, the CV-22’s total O&S costs nearly doubled. According to officials,
this increase can largely be attributed to the overall increase in the number of aircraft. Maintenance costs also
increased by $140.8 million between fiscal year 2011 and 2018, accounting for about 40 percent of O&S costs over
the period. Further, depot-level reparables, the most significant category of maintenance costs, increased from
$58.14 million in fiscal year 2011 to $159.59 million in fiscal year 2018.




Page 200                                                                        GAO-21-101SP Weapon System Sustainment
CV-22 Total Operating and Support Costs




The CV-22’s total O&S costs per aircraft decreased steadily from fiscal year 2011 through fiscal year 2016 before
increasing slightly in fiscal years 2017 and 2018. Specifically, O&S costs per aircraft decreased from $25.60 million
in fiscal year 2011 to $16 million in fiscal year 2016 and increased to $17.7 million in fiscal year 2018, while the
mission capable rate varied. Maintenance costs per aircraft, on average, accounted for about 40 percent of the total
O&S costs per aircraft from fiscal years 2011 through 2018, averaging about $7.68 million per year. Additionally, the
number of aircraft more than doubled, from 18 aircraft in fiscal year 2011 to 50 aircraft in fiscal year 2019, with a
total expected fleet of 52 aircraft.




Page 201                                                                       GAO-21-101SP Weapon System Sustainment
CV-22 Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Maintenance: According to Joint Program Office officials, the CV-22 currently has too many configurations—22 in
total—for the Joint Program Office to maintain adequately and consistently. To mitigate this issue, the Joint Program
Office plans to reduce the number of configurations and ultimately achieve either a common configuration or a
minimal number of configurations, which officials hope will result in less time spent on unplanned maintenance and
aircraft inspections. The full completion of the initiative is planned for fiscal year 2027. Further, officials told us that
the configuration challenge affects depot maintenance times, which decreases availability. The Joint Program Office
plans to mitigate this challenge through an aggressive modification program to achieve the common configuration.
Joint Program Office officials also told us aircraft availability and mission capability have both been negatively
affected by low reliability of wiring and other components. To address these issues, the Joint Program Office is
working to fully fund the current and future corrective action plans and engineering proposals to improve the
reliability of these components. Lastly, the Joint Program Office stated that it has awarded a Performance Based
Logistics and Engineering (PBL&E) contract that directly incentivizes industry to align with fleet goals of reducing the
number of “long-term down” aircraft and reduce the NMCM rate. According to the Joint Program Office, the PBL&E
contract also incentivizes rapid engineering responses, which should improve mission capable rates by reducing
awaiting maintenance time, eliminating technical data gaps, and informing root cause and corrective actions.

Supply Support: The CV-22 has experienced spare part availability issues due to the number of configurations for
the aircraft, which officials are working to mitigate in several ways. For example, Joint Program Office officials told
us that they are working to implement a common configuration, as stated above, which will reduce the demand on
the supply system. The CV-22 has also experienced supply issues when the necessary parts were not readily
available to install due to there being no previous demand for the specific part and issues with suppliers. The Joint
Program Office plans to improve consumable and reparable material support for the fleet by having the Air Force
and the Defense Logistics Agency partner to more accurately measure the need for specific parts to ensure the
most needed parts are available for purchase. The Joint Program Office also reports pursuing a number of
initiatives, such as working with Navy Supply Systems Command and the Defense Logistics Agency to award
contracts incentivizing material availability. The CV-22 has experienced supply shortages after some manufacturers
stopped making certain CV-22 parts. According to officials, the program office has purchased additional parts and
developed incentives for manufacturers to help ensure there are sufficient parts to effectively maintain the fleet
throughout its lifetime, among other things.



Page 202                                                                            GAO-21-101SP Weapon System Sustainment
 Program Office Comments
In commenting on a draft of this assessment, the Joint Program Office stated that its efforts initiated in fiscal years
2018 and 2019 to accelerate readiness recovery produced results in fiscal year 2019 and will continue to improve
readiness. Specifically, the Joint Program Office stated that the CV-22 in fiscal year 2019 was able to meet the fiscal
year 2019 flight hour goal. The Joint Program Office noted that the improvements it has made should continue to
result in improved CV-22 readiness rates in the future.




Page 203                                                                        GAO-21-101SP Weapon System Sustainment
                                     HH-60G Pave Hawk Sustainment Quick Look
                                     Common Name: HH-60G
                                     Lead Service: Air Force

                                     Background
Program Essentials                   The HH-60G Pave Hawk is a twin engine helicopter first manufactured in
Manufacturer: United                 1982. Its primary mission is to conduct day or night personnel recovery
Technologies/Sikorsky Aircraft       operations into hostile environments to recover isolated personnel during
Company                              war. The HH-60G is also tasked to perform military operations other than
                                     war, including civil search and rescue, medical evacuation, disaster
Sustainment: Programmed depot        response, and humanitarian assistance.
maintenance is conducted by
government and contractor            Life Cycle of the HH-60G
personnel at various locations and
field-level maintenance is
performed by Air Force personnel
Program Office: Robins Air Force
Base, Georgia
Fiscal Year 2019 Data
Average age: 27.5 years              Overview
Average lifetime flying hours:       The HH-60G fleet met the Air Force’s aircraft availability goals in two years
7070.5 hours per aircraft            from fiscal years 2011 through 2019 and met the mission capable goal in one
                                     of those years. However, in fiscal year 2019, the HH-60G did not meet its
Depot maintenance activity
                                     aircraft availability goal or mission capable goal. From fiscal year 2011
and squadron locations:
                                     through fiscal year 2018, total operating and support (O&S) costs for the HH-
                                     60G fleet decreased by $169.60 million, from $983.84 million to $814.24
                                     million. Over the same 8-year period, the HH-60G fleet size decreased from
                                     99 to 97 aircraft, including two test aircraft in fiscal year 2018, according to
                                     Air Force officials. The total O&S costs per aircraft decreased from $9.94
                                     million in fiscal year 2011 to $8.39 million in fiscal year 2018, while the
                                     maintenance costs per aircraft increased slightly from $2.08 million to $2.12
                                     million during the same timeframe.

                                     HH-60G Sustainment Status




Sustainment Challenges
and Mitigation Actions
The HH-60G faces several
maintenance and supply
challenges, such as prolonged
depot maintenance timelines and
malfunctioning parts. Mitigation
actions include improving the
planning of depot maintenance
and coordinating across the
military on supply support issues.


Page 204                                                                      GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The March 2017 HH-60G Weapon System Life-Cycle Sustainment Plan Version 1.0 Supporting Operations and
   Support Phase outlines the sustainment strategy for the legacy HH-60G weapon system. According to the plan,
   the basic H-60 helicopter is operated by the Air Force, Army, Navy, and Coast Guard, and those services, in
   addition to contractors, all play a role in HH-60G sustainment. According to Air Force officials, the HH-60G fleet
   is sustained through scheduled inspections, field and depot technical assistance requests, and programmed
   depot maintenance (performed every 6.5 years). Additionally, these officials stated that structural, maintenance,
   reliability, and diminishing manufacturing sources and material shortages modifications are made to the aircraft.

•   Programmed depot maintenance is conducted by government and contractor personnel at Corpus Christi Army
    Depot, Navy Fleet Readiness Center Southeast, and Korean Air Lines, among other locations. Field-level
    maintenance is performed by Air Force, Air Force Reserve Command, and Air National Guard personnel.
    Supply support is managed by the Air Force Sustainment Center, Army Materiel Command, Naval Air Systems
    Command, and the Defense Logistics Agency. Officials explained that the Air Force plans to end HH-60G
    programmed depot maintenance inductions in fiscal year 2020 due to planned aircraft retirements and deliveries
    of the replacement aircraft (the HH-60W).


 Availability and Condition
The HH-60G fleet met the Air Force’s aircraft availability goals in two years during fiscal years 2011 through 2019
and met the mission capable goal in one year. According to Air Force officials, the low HH-60G availability rate was
largely a result of a smaller fleet size than originally planned due to operational losses from aircraft mishaps.
Specifically, the HH-60G program of record was 112 aircraft, but the aircraft inventory was between 99 and 97 in
fiscal years 2011 and 2018, including two test aircraft in fiscal year 2018, which reduced the program’s ability to
achieve the availability rate goal. Air Force officials said that the two test aircraft were a part of their operational loss
replacement program. The officials told us that the decline in availability was also a result of increased downtime
stemming from the aircraft’s heavy modification schedule and depot performance issues, among other reasons.1

The not mission capable for maintenance (NMCM) rate for the HH-60G fleet varied from fiscal years 2011 through
2019. The not mission capable for supply (NMCS) rate also varied. The not mission capable for both (NMCB) rate
trended upwards from fiscal year 2011 to fiscal year 2019. According to Air Force officials, functional check flight
delays—the flight required to assess the airborne function of certain repaired or replaced components—was the
leading NMCM driver for the fleet. The officials said that functional check flights increased since fiscal year 2013
because the aging HH-60G is often used at its maximum gross weight, which causes airframe structural issues and
cracking and additional maintenance to remove and reinstall components. Air Force officials also told us that the
NMCS rate was higher in fiscal years 2016 through 2018 largely due to a problem with the aircraft’s refueling
probes. Unusual numbers of refueling probe oscillations began to occur in fiscal year 2011, with the most occurring
in fiscal year 2015. The research and investigation of the problem took several years until the cause was identified
in November 2015. According to program officials, fixing the problem required removing all affected refueling probes
from the inventory and replacing them, with the last aircraft being repaired in December 2018. Officials noted that
the HH-60G’s main rotor blade was the largest NMCS driver in fiscal year 2019. Finally, the NMCB rate was higher
in fiscal years 2016 through 2019 because of parts shortages that led to cannibalization (i.e., removing serviceable
parts from one aircraft and installing them in another aircraft), according to Air Force officials. Data provided by
these officials showed that the refueling probe and the main rotor blade were two examples of parts that were
cannibalized due to shortages and that impacted the HH-60G’s NMCB rate during those years. Specific details on
mission capable and not mission capable rates were omitted because the information was deemed by DOD to be
sensitive.


 Operating and Support Costs
From fiscal year 2011 through 2018, the total O&S costs for the HH-60G fleet decreased by about $169.60 million,
from $983.84 million to $814.24 million. When comparing the two fiscal years, most of the decrease was due to a
reduction in costs for continuing systems improvements. Continuing system improvements were $292.13 million less

1GAO,  Military Readiness: Air Force Plans to Replace Aging Personnel Recovery Helicopter Fleet, GAO-18-605 (Washington, D.C.:
Aug. 16, 2018). We reported that HH-60G helicopters spent an average of 332 days undergoing depot level maintenance in fiscal year
2017 compared with 233 days in fiscal year 2007, more than a 40-percent increase. Air Force officials attributed these challenges to the
helicopters exceeding their initially planned service life.

Page 205                                                                                    GAO-21-101SP Weapon System Sustainment
in fiscal year 2011 than in fiscal year 2018, but these costs were significantly higher in fiscal year 2011 than the
other years in the time period. According to HH-60 program officials, seven major modifications were ongoing during
fiscal year 2011, including a service life extension, a gun replacement, and the operational loss replacement
program to restore the fleet’s aircraft inventory. The $218.45 million spent on the operational loss replacement
program in fiscal year 2011 was likely the primary reason why continuing system improvement costs were higher in
fiscal year 2011, according to these officials. Maintenance costs were almost the same in fiscal years 2011 and
2018, $206.27 million and $205.61 million respectively. The remaining cost categories all increased during the 8-
year period, with unit operations and unit-level manpower increasing the most, by $63.56 million and $29.85 million,
respectively. Program officials noted that higher fuel costs and additional training requirements following significant
Air Force-wide personnel cuts were two of the reasons for the higher unit operations costs.


HH-60G Total Operating and Support Costs




The total O&S costs per aircraft decreased from $9.94 million in fiscal year 2011 to $8.39 million in fiscal year 2018.
Over the 8-year period, the HH-60G fleet size decreased––from 99 to 97 aircraft––and total O&S costs decreased
by about $169.60 million, reducing the total O&S costs per aircraft. However, maintenance costs were almost the
same in fiscal years 2011 and 2018, $206.27 million and $205.61 million, respectively. Therefore, maintenance
costs per aircraft went up slightly, from $2.08 million to $2.12 million, when comparing those two fiscal years.




Page 206                                                                         GAO-21-101SP Weapon System Sustainment
HH-60G Operating and Support Costs per Aircraft and Fleet Size




 Sustainment Challenges and Mitigation Actions
Maintenance: For many years, the HH-60G program has had a higher rate of operational losses than Air Force
officials said were planned, an average of one aircraft every 24 months. The ongoing operational loss replacement
program will replace these aircraft by modifying UH-60L aircraft to the HH-60G configuration and will increase the
fleet’s aircraft availability rate. Air Force officials explained that two test aircraft were delivered in fiscal year 2018, 10
aircraft were delivered between July 2019 and March 2020, and nine aircraft are to be delivered by December 2020
under the operational loss replacement program. Also, functional check flights—the flights required to assess the
airborne function of certain repaired or replaced components—have increased, and the delay in obtaining these
functional flight checks has become leading NMCM driver for the aging HH-60G fleet, according to Air Force
officials. To mitigate this issue, the officials said that they plan to perform an engineering analysis in fiscal year 2020
to determine what can be accomplished on the ground instead of during a flight. Air Force officials also told us that
the HH-60G program faces challenges with downtime for modifications and programmed depot maintenance. To
reduce the number of aircraft that are down for depot maintenance at one time, the officials said that they started to
combine the installation of multiple modifications into blocks and manage the timing of scheduled depot inductions
more effectively in fiscal year 2019. However, they found that depot induction schedule changes have increased
field maintenance requirements with additional inspections and limited the ability of units to accurately plan flying
hour and inspection schedules.

Supply Support: Air Force officials said that the aging fleet, the lack of vendors, and the lack of primary inventory
control authority to manage HH-60G parts are several supply support challenges for the HH-60 fleet. The HH-60G
program office is an active member of the Team Hawk working group, which works to help solve ongoing
sustainment issues and to benefit from the other services’ lessons learned, according to Air Force officials. They
explained that the Team Hawk working group is a collaboration between the Air Force, Army, Coast Guard, Navy,
and the H-60 original equipment manufacturer, to identify and solve sustainment challenges, discuss technical
issues, classify risk areas, discuss and investigate collaboration opportunities, and identify parts obsolescence
among key stakeholders. Further, HH-60 program officials said that they manage engineering services and reliability
and maintainability contracts that give reach-back capabilities to manufacturers and small businesses to identify,
study, and solve sustainment and engineering issues. Finally, they stated that an obsolescence/diminishing
manufacturing sources and material shortages lead is assigned to the HH-60G program office to identify items with
immediate or near-term obsolescence issues, assess the population of problem items, and prioritize the items that
are most at risk for current and future readiness.


Page 207                                                                              GAO-21-101SP Weapon System Sustainment
 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.




Page 208                                                                    GAO-21-101SP Weapon System Sustainment
                                        UH-1N Iroquois Aircraft Sustainment Quick Look
                                        Common Name: UH-1N
                                        Lead Service: Air Force

                                        Background
Program Essentials                      The UH-1N Iroquois is a light-lift utility aircraft that was first manufactured in
Manufacturer: Bell                      1956 and last produced in 1974. The aircraft has a crew of three and is
Helicopter/Textron, Inc.                capable of flight in inclement weather and nighttime conditions. The UH-1N
                                        supports combatant command missions and enables Air Force aircrews to
Sustainment: Depot maintenance          conduct airlifts of emergency security forces and distinguished visitors, and to
conducted at Navy Fleet                 conduct security and surveillance of off-base nuclear weapons convoys.
Readiness Center – East and field
maintenance conducted by                Life Cycle of the UH-1N
contractors
Program Office: Air Force Life
Cycle Management Center,
Robins Air Force Base, Georgia
Fiscal Year 2019 Data
Average age: 47 years
Average lifetime flying hours:          Overview
14,900 hours per aircraft               The UH-1N fleet exceeded its mission capable goal in each year from fiscal
Depot maintenance activity              year 2011 to fiscal year 2019, and exceeded its aircraft availability goal in
and squadron locations:                 three years during that same time period. In fiscal year 2019, the UH-1N fleet
                                        did not meet its aircraft availability goal, but exceeded its mission capable
                                        rate goal. Operating and support (O&S) costs per aircraft increased from
                                        about $3.89 million in fiscal year 2011 to about $4.67 million in fiscal year
                                        2018 as a result of an increase in UH-1N maintenance costs.

                                        UH-1N Sustainment Status




 Sustainment Challenges
 and Mitigation Actions
The UH-1N is experiencing many
challenges related to its age.
Officials told us plans to retire the
aircraft beginning in 2022 will
mitigate aging issues, with full
retirement expected by 2032.




Page 209                                                                          GAO-21-101SP Weapon System Sustainment
 Sustainment Strategy
• The UH-1N Replacement Life-Cycle Sustainment Plan (2018) provides the overall framework for the
   sustainment of the UH-1N system and its replacement, the MH-139A. This plan documents the UN-1N
   program’s product support and total life cycle support management strategies, and provides plans to sustain the
   UH-1N while it is being replaced— from 2022 through 2032.

•   The program office extended its engineering services support contract with Bell Helicopter Textron, Inc. in
    December 2018 for the UH-1N fleet to provide engineering assistance with repair questions and modifications.

•   The Navy Fleet Readiness Center – East conducts depot maintenance, and the Army is responsible for
    conducting depot-level maintenance on reparable components. Contractor field maintainers provide
    organizational and intermediate maintenance for the UH-1N at the squadron level. Army, Navy, Air Force, and
    Defense Logistics Agency item managers provide supply support.


 Availability and Condition
The UH-1N fleet exceeded its mission capable goal in each year from fiscal year 2011 to fiscal year 2019, and
exceeded its aircraft availability goal in three years during that same time period.

From fiscal year 2011 through fiscal year 2019, the rates for not mission capable supply (NMCS) and both
maintenance and supply (NMCB) stayed fairly constant, while the not mission capable maintenance (NMCM) rate
slightly increased. According to officials, the NMCM rate increased due to increased times to remove and re-install
components on aircraft due to the age of the aircraft. Specific details on mission capable and not mission capable
rates were omitted because the information was deemed by DOD to be sensitive.

 Operating and Support Costs
From fiscal year 2011 through fiscal year 2014, the UH-1N’s total O&S costs decreased and then increased from
fiscal year 2015 through fiscal year 2017, before slightly dropping again in fiscal year 2018. The increase in costs
from fiscal year 2014 to fiscal year 2018 was primarily due to an increase in maintenance costs, from $47.65 million
in fiscal year 2014 to $111.65 million in fiscal year 2018. According to officials, increases in costs also occurred due
to errors in the Air Force Total Ownership Cost database that included TH-1H—an Iroquois training aircraft—engine
repair contract costs, and other support costs with the UH-1N.




Page 210                                                                          GAO-21-101SP Weapon System Sustainment
UH-1N Total Operating and Support Costs




The UH-1N’s total O&S costs per aircraft increased from $3.89 million in fiscal year 2011 to $4.67 million in fiscal
year 2018. Specifically, O&S costs per aircraft decreased from $3.89 million in fiscal year 2011 to $3.12 million in
fiscal year 2014. Since fiscal year 2014, O&S costs per aircraft increased to a high of $5.01 million in fiscal year
2017 before decreasing slightly to $4.67 million in fiscal year 2018. This increase was largely attributable to an
increase in maintenance costs, specifically contractor logistics support, depot-level reparables, and depot
maintenance. Maintenance costs per aircraft were generally stable from fiscal year 2011 through fiscal year 2015,
averaging about $0.81 million per year before increasing to an average of $1.7 million from fiscal year 2016 through
fiscal year 2018. As previously discussed, according to officials, increases in costs occurred because of errors in the
Air Force Total Ownership Cost database that included TH-1H—an Iroquois training aircraft—engine repair contract
costs and other support costs with the UH-1N. Additionally, the number of aircraft decreased from 78 aircraft in fiscal
year 2011 to 63 aircraft in fiscal year 2018, as the aircraft approaches its phased retirement beginning in 2022 and
concluding in 2032. However, according to officials, TH-1H aircraft may have been captured in the number of
aircraft, erroneously inflating the number of aircraft between fiscal years 2011 and 2013.




Page 211                                                                        GAO-21-101SP Weapon System Sustainment
UH-1N Operating and Support Costs per Aircraft and Fleet Size




Sustainment Challenges and Mitigation Actions
Aging: According to officials, the age of aircraft components and high number of usage hours has created additional
maintenance to remove or reinstall components, which has led to an increase to NMCM time. Further, the Air Force
is currently buying over 150 new main rotor blades due to the aging-related high failure rate on the repair line, which
negatively impacts the mission capable and aircraft availability rates, according to officials.

Maintenance: According to officials, the aging fleet and lack of repair of UH-1N components has led to maintenance
sustainment challenges and unpredictable aircraft schedules. This has prevented units from being able to accurately
plan flying hour and inspection schedules, which has resulted in last-minute changes and an increase in unit
maintenance. Additionally, officials stated that the main rotor blade replacements have increased NMCM time due to
the requirement for a functional check flight prior to returning aircraft to mission capable status.

Supply Support: According to officials, Defense Logistics Agency parts shortages and tester issues have not
allowed the Air Force to keep up with transmission parts demands for the UH-1N. Further, there have also been
transmission supply shortage issues—which are repaired by the Army—for the Air Force.

To address sustainment challenges, the UH-1N program office continues to proactively work with the other services
to improve the sustainment program across the common H-1 platform. According to officials, they monitor both
internal and external sustainment providers to ensure issues are resolved as quickly as possible for minimal impact
to overall aircraft availability. For example, one of the supply partners was unable to deliver enough rotor blades. As
a result, the services authorized pulling blades from the aircraft in storage to prevent a gap in support until the new
blades were delivered. Officials also said that the program office is executing an obsolescence program to minimize
costs and offset detrimental sustainment impact, which includes meetings to discuss sustainment issues as they
arise.


 Program Office Comments
In commenting on a draft of this assessment, the program office provided technical comments, which we
incorporated where appropriate.



Page 212                                                                         GAO-21-101SP Weapon System Sustainment
                  We provided a draft of the sensitive report to DOD for review and
Agency Comments   comment. DOD provided technical comments which we incorporated
                  where appropriate.

                  We are sending copes of this report to the appropriate congressional
                  committees, the Secretary of Defense, the Under Secretary of Defense
                  for Acquisition and Sustainment, the Assistant Secretary of Defense for
                  Sustainment, and the Secretaries of the Army, the Navy, and the Air
                  Force. In addition, the report is available at no charge on the GAO
                  website at https://www.gao.gov.

                  If you or your staff have any questions about this report, please contact
                  me at (202) 512-9627 or maurerd@gao.gov. Contact points for our
                  Offices of Congressional Relations and Public Affairs may be found on
                  the last page of this report. GAO staff who made key contributions to this
                  report are listed in appendix III.




                  Diana Maurer
                  Director, Defense Capabilities and Management




                  Page 213                               GAO-21-101SP Weapon System Sustainment
List of Requesters

The Honorable James M. Inhofe
Chairman
Committee on Armed Services
United States Senate

The Honorable Dan Sullivan
Chairman
The Honorable Tim Kaine
Ranking Member
Subcommittee on Readiness and Management Support
Committee on Armed Services
United States Senate

The Honorable John Garamendi
Chairman
The Honorable Doug Lamborn
Ranking Member
Subcommittee on Readiness
Committee on Armed Services
House of Representatives




Page 214                         GAO-21-101SP Weapon System Sustainment
Appendix I: Objectives, Scope, and
              Appendix I: Objectives, Scope, and
              Methodology


Methodology

              This report provides observations on (1) the extent to which the military
              departments met mission capable goals for 46 fixed- and rotary-wing
              types of aircraft, including trends since fiscal year 2011 in mission
              capable rates and any sustainment challenges for those aircraft; and (2)
              the costs to operate and support these aircraft since fiscal year 2011.

              This is a public version of a sensitive report that we issued in August
              2020. 1 DOD deemed some of the information in our August report to be
              sensitive (i.e., For Official Use Only), which must be protected from public
              disclosure. Therefore, this report omits sensitive information about
              mission capable and aircraft availability rates. Although the information
              provided in this report is more limited, the report addresses the same
              objectives as the sensitive report and uses the same methodology.

              Our observations are based on 46 manned fixed- and rotary-wing types of
              aircraft that support combat-related missions in the Departments of the
              Army, Navy, and Air Force. 2 In selecting these aircraft, we considered a
              number of factors, such as the mission of the aircraft (e.g., fighters,
              bombers, or cargo) and the size and age of the inventory for each aircraft.
              For example, we did not select aircraft that are used solely for training or
              are used to meet the operational airlift support mission (i.e., the
              movement of a limited number of high-priority passengers and cargo with
              time, place, or mission-sensitive requirements). 3

              Figure 4 below lists the aircraft reviewed, by type and military department.




              1GAO, Weapon System Sustainment: Aircraft Mission Capable Rates Generally Did Not
              Meet Goals and Cost of Sustaining Selected Weapon Systems Varied Widely,
              GAO-20-67SPSU (Washington, D.C.: August 27, 2020).
              2Aircraft   flown by the Marine Corps are included in the data on the Department of the
              Navy.
              3We    reported on operational support airlift in June 2017. See GAO, Operational Support
              Airlift: Fleet Sufficiency Is Assessed Annually, GAO-17-582 (Washington, D.C.: June 28,
              2017).




              Page 215                                         GAO-21-101SP Weapon System Sustainment
Appendix I: Objectives, Scope, and
Methodology




Figure 4: Aircraft Selected for Review by GAO




For objective one, we collected and analyzed data from the Army, Navy,
and Air Force as well as the F-35 Joint Program Office on key




Page 216                                  GAO-21-101SP Weapon System Sustainment
Appendix I: Objectives, Scope, and
Methodology




sustainment metrics for each of the 46 aircraft. 4 These metrics included
mission capable rates and goals and not mission capable rates for
maintenance, supply, and both for fiscal years 2011 through 2019, the
last fiscal year for which complete data were available at the time of our
work. For Air Force aircraft and the F-35, we also collected and analyzed
data on aircraft availability rates and goals for fiscal years 2011 through
2019. 5 We selected this time frame so that we could identify and obtain
insight on mission capable rate trends. In addition, we obtained
information from program office officials regarding the reasons for
changes in mission capable rates and aircraft availability rates as well as
any challenges in sustaining these aircraft. We also discussed with
program office officials any ongoing and planned actions to address those
challenges. We reviewed those challenges and summarized them in three
broad categories: aging aircraft, maintenance, and supply support. We
further summarized these challenges with several sub-categories and
presented these challenges in a summary figure. Further, we obtained
and reviewed documents, including life-cycle sustainment plans and
aircraft availability improvement plans.

For objective two, we collected and analyzed operating and support
(O&S) cost data from the Departments of the Army, Navy, and Air Force
cost reporting systems. 6 Specifically, we collected O&S cost data for
fiscal years 2011 through 2018, the last fiscal year for which complete
data were available at the time of our work. 7 We selected this time frame
so that we could identify and obtain insight on the historical data trends


4Mission capability data were pulled from the Logistics Information Warehouse Readiness
Integrated Data Base for the Army; the Decision Knowledge Programming for Logistics
and Technical Evaluation (DECKPLATE) and the Aviation Maintenance Supply Readiness
Reporting (AMSRR) information systems for the Navy; Logistics, the Installations and
Mission Support – Enterprise View system for the Air Force; and the Sustainment
Performance Management System via the Autonomic Logistics Information System for the
F-35.
5The   Air Force refers to the aircraft availability goals as the aircraft availability standard.
6Specifically,
            we obtained information from the Army’s Operating and Support
Management Information System (OSMIS), the Navy Visibility and Management of
Operating and Support Costs system (VAMOSC), and the Air Force Total Ownership Cost
system (AFTOC).
7We  report on Army O&S trends through fiscal year 2017. We obtained fiscal year 2018
O&S cost data from the Army, but we learned from the Army that the data were
inaccurate. Thus, the costs presented for the Army are based on fiscal year 2017 O&S
data.




Page 217                                            GAO-21-101SP Weapon System Sustainment
Appendix I: Objectives, Scope, and
Methodology




regarding O&S costs. 8 We also obtained information from program office
officials about the reasons for changes and trends in O&S costs.

We conducted data reliability assessments for the data provided by the
military departments and the F-35 Joint Program Office. To do this, we
reviewed related documentation; held interviews with knowledgeable
agency officials; and performed electronic data testing for missing data,
outliers, and obvious errors. Additionally, we shared the mission capable
rate and O&S cost data with the program offices that manage each
individual type of aircraft for review and comment, to ensure the accuracy
of the data presented. Lastly, the Army, Navy, and Air Force, as well as
the F-35 Joint Program Office, use these data to manage the sustainment
of aircraft. As a result, we determined these data to be sufficiently reliable
for the purposes of summarizing trends in mission capable rates and O&S
costs since fiscal year 2011. 9

To develop the Sustainment Quick Looks on each aircraft, we obtained
historical and current information, including background on aircraft
capabilities, manufacturers, sustainment strategies, depot maintenance
and squadron locations, and key dates in the life cycle of each aircraft
(e.g., first manufactured, initial and full operational capability, last
production, and planned sunset year). We used this information, as well
as the information collected for objectives one and two on readiness and
O&S costs, in each Sustainment Quick Look. In the Quick Looks, we
compared mission capable and aircraft availability rates to goals set by
the military departments. We analyzed O&S costs, including maintenance
sub-categories, and compared the costs to readiness trends. We also
obtained and reviewed sustainment documentation on each aircraft, such
as life-cycle sustainment plans and aircraft availability plans, and we
discussed sustainment plans and activities with knowledgeable program
officials. Through interviews with knowledgeable officials and reviewing
documentation, we identified sustainment challenges and mitigation
actions to address these challenges.

We conducted this performance audit from August 2018 to July 2020 in
accordance with generally accepted government auditing standards.
Those standards require that we plan and perform the audit to obtain
sufficient, appropriate evidence to provide a reasonable basis for our

8O&S   costs are adjusted for inflation and presented in fiscal year 2018 constant dollars.
9Aspreviously noted, we did not report fiscal year 2018 O&S cost data from the Army
because we learned from the Army that the data provided to us were inaccurate.




Page 218                                         GAO-21-101SP Weapon System Sustainment
Appendix I: Objectives, Scope, and
Methodology




findings and conclusions based on our audit objectives. We believe that
the evidence obtained provides a reasonable basis for our findings and
conclusions based on our audit objectives. We subsequently worked with
DOD from August 2020 to November 2020 to prepare this unclassified
version of the original sensitive report for public release. This public
version was also prepared in accordance with these standards.




Page 219                             GAO-21-101SP Weapon System Sustainment
Appendix II: Additional Information on Navy
              Appendix II: Additional Information on Navy
              Aircraft Mission Capable Rates


Aircraft Mission Capable Rates

              The Navy uses mission capable rate data from its Aviation Maintenance
              Supply Readiness Reporting (AMSRR) information technology system to
              evaluate its progress against the Secretary of Defense’s 80 percent
              mission capable rate goal as it measures mission capability at a point in
              time on each day. 1 The Navy also maintains mission capable rate data as
              well as other sustainment data in its Decision Knowledge Programming
              for Logistics Analysis and Technical Evaluation (DECKPLATE)
              information technology system, which Navy officials acknowledge
              provides a more comprehensive measure of the health of aircraft,
              systems, and components. DECKPLATE measures mission capability
              based on a percentage of the total time the aircraft is available and
              provides additional insight into the reasons for an aircraft not being
              mission capable, such as not mission capable maintenance and supply
              rates.

              For each of the 19 Navy and Marine Corps aircraft, AMSRR mission
              capable rates are higher than DECKPLATE mission capable rates.
              Additionally, while only one aircraft met the mission capable goal during
              fiscal year 2019 using DECKPLATE mission capable rates, three
              aircraft—EP-3E Aries II, E-6B Mercury, and F/A-18A-D Hornet—met the
              goals using AMSRR mission capable rate data.

              Comparing AMSRR mission capable rates from fiscal year 2018 to fiscal
              year 2019 for the selected aircraft shows that twelve of the 19 aircraft
              showed an improvement, one aircraft was constant, and six showed a
              decline in mission capable rates.




              1Secretary of Defense Memorandum, NDS Implementation—Mission Capability of Critical
              Aviation Platforms (Sept. 17, 2018).




              Page 220                                      GAO-21-101SP Weapon System Sustainment
Appendix III: GAO Contact and Staff
                  Appendix III: GAO Contact and Staff
                  Acknowledgments


Acknowledgments

                  Diana Maurer, (202) 512-9627 or maurerd@gao.gov.
GAO Contact
                  In addition to the contact named above, John Bumgarner (Assistant
Staff             Director), Clarine Allen, Leslie Bharadwaja, Vincent Buquicchio, Amy
Acknowledgments   Bush, Christopher Gezon, Chad Hinsch, James Lackey, Amie Lesser,
                  Edward Malone, Jacqueline McColl, Richard Powelson, Janine Prybyla,
                  Cheryl Weissman, Melissa Wohlgemuth, and Lillian Yob made key
                  contributions to this report.




(104507)
                  Page 221                              GAO-21-101SP Weapon System Sustainment
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