oversight

Electronic Warfare: Towed Decoys Could Improve Survivability of Current Navy Aircraft

Published by the Government Accountability Office on 1997-09-04.

Below is a raw (and likely hideous) rendition of the original report. (PDF)

                  United States General Accounting Office

GAO               Report to Congressional Committees




September 1997
                  ELECTRONIC
                  WARFARE
                  Towed Decoys Could
                  Improve Survivability
                  of Current Navy
                  Aircraft




GAO/NSIAD-97-94
                   United States
GAO                General Accounting Office
                   Washington, D.C. 20548

                   National Security and
                   International Affairs Division

                   B-272628

                   September 4, 1997

                   Congressional Committees

                   We have completed our review of the Department of Defense’s (DOD)
                   acquisition plans for the ALE-50 towed decoy system and the Radio
                   Frequency Countermeasures System (RFCM), which includes a more
                   advanced towed decoy. The RFCM is part of the Integrated Defensive
                   Electronics Countermeasures System being developed for some Navy and
                   Air Force aircraft. Our objective was to determine whether towed decoys
                   could improve the survivability of these aircraft. In addition, because
                   Congress has expressed concern for F/A-18C/D survivability, we are
                   issuing this report to bring to your attention the opportunity towed decoy
                   systems offer to potentially enhance survivability of the F/A-18C/D.


                   DOD’s effort to improve the survivability of its aircraft through the use of
Results in Brief   towed decoys has demonstrated positive results. According to test reports
                   and test officials, the ALE-50 has done very well in effectiveness testing
                   and the future RFCM decoy system is expected to be even more capable.
                   The Air Force is actively engaged in efforts to field towed decoy systems
                   on a number of its current aircraft, including the F-15, F-16, and B-1, while
                   the Navy is planning towed decoys only for its future F/A-18E/F.

                   In the year 2010, almost 50 percent of the Navy’s tactical fighter inventory
                   will still be current generation fighter aircraft such as the F/A-18C/D, even
                   if new F/A-18E/Fs are procured at the rates desired by the Navy between
                   now and then. Hence, improving the survivability of the F/A-18C/D, as well
                   as other current Navy and Marine Corps aircraft, potentially offers the
                   opportunity to save additional aircraft and aircrew’s lives in the event of
                   future hostilities and also addresses congressional concerns expressed for
                   F/A-18C/D survivability.


                   Traditionally, DOD’s combat aircraft have used on-board electronic warfare
Background         devices called jammers for self-protection against radar-controlled
                   weapons, including missiles and anti-aircraft artillery. These jammers emit
                   electronic signals from the aircraft to try to impede or deny the threat
                   radar’s ability to locate the aircraft. DOD’s existing self-protection jamming
                   systems for its tactical aircraft have limitations against certain threats, and
                   these threats are expected to be improved. DOD has modified existing
                   systems, such as the Air Force’s ALQ-131 used on the F-16 and the




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                        B-272628




                        ALQ-135 on the F-15, and has developed a newer system, the Navy’s
                        Airborne Self-Protection Jammer (ASPJ), which is being used on some
                        F-14D and F/A-18C/D aircraft. As we have previously reported, however,
                        testing after deployment has shown that the modified jammer systems
                        have had problems,1 while operational testing of ASPJ and other jammers
                        showed they were unable to meet effectiveness criteria against certain
                        classified threats.2

                        In an attempt to overcome the limitations of the on-board jammers, the
                        services are acquiring two new towed decoy systems, the ALE-50 and the
                        RFCM, to enhance survivability against the radar-controlled threats. The
                        ALE-50 towed decoy system is in production, while the future RFCM system
                        is in development. The ALE-50’s towed decoy component generates and
                        emits its own signals that are intended to lure an incoming radar-guided
                        weapon away from the aircraft by presenting a more attractive target. To
                        provide further improvement for selected Air Force and Navy aircraft, the
                        RFCM is to provide more sophisticated techniques than the ALE-50. A
                        jamming device called the techniques generator carried onboard the
                        aircraft produces jamming signals that are transmitted by fiber optic cable
                        to the RFCM decoy for transmission.

                        Both decoys are single use systems. Once deployed from the aircraft, the
                        decoy’s tow line is severed prior to return to base. Each aircraft is to carry
                        multiple decoys, so if one is destroyed by enemy fire or malfunctions,
                        another can be deployed. Therefore, substantial inventories of decoys are
                        required to sustain potential combat operations. The services expect that
                        these decoys will improve survivability of their aircraft against
                        radar-controlled threats compared to the current technique of emitting the
                        jamming signals directly from the aircraft.


                        Classified test results show that the ALE-50 towed decoy offers improved
Towed Decoys Can        effectiveness against radar-controlled threats, including some threat
Enhance Survivability   systems against which self-protection jammers have shown little to no
                        effectiveness.3 Moreover, the future RFCM decoy system is expected to
                        further improve survivability due to its more sophisticated jamming
                        techniques.


                        1
                         Electronic Warfare: Need to Strengthen Controls Over Air Force Jammer Programs
                        (GAO/NSIAD-90-168, July 11, 1990) and Electronic Warfare: Most Air Force ALQ-135 Jammers
                        Procured Without Operational Testing (GAO/NSIAD-95-47, Nov. 22, 1994).
                        2
                         Airborne Self-Protection Jammer (GAO/NSIAD-97-46R, Jan. 29, 1997.)
                        3
                         Performance against specific threat systems is considered classified.


                        Page 2                              GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
                        B-272628




                        Recognizing the potential offered by these towed decoy systems to
                        overcome the limitations of using just on-board jammers, such as the ASPJ,
                        the Air Force is actively pursuing the use of towed decoys for its current
                        aircraft. It has done the necessary modifications to add the ALE-50 to the
                        F-16, an aircraft slightly smaller than the Navy’s F/A-18C/D, and to the B-1,
                        a much larger aircraft. The Air Force is also considering use of the RFCM
                        decoy system on the F-15, which will use its existing on-board jammer
                        instead of the techniques generator, and on the B-1, as well as several
                        other aircraft. The Navy plans to equip only its future F/A-18E/F aircraft
                        with a decoy system.

                        The ALE-50 decoy system is to be used by the Air Force on 437 F-16 and
                        95 B-1 aircraft. In addition to the ALE-50 components such as the launcher
                        and controller installed on the aircraft, the Air Force plans to procure
                        17,306 ALE-50 decoys to meet operational requirements. The Navy plans to
                        buy 466 ALE-50 decoys. These will be used for F/A-18E/F testing and
                        contingencies after the aircraft’s deployment until the RFCM decoy is
                        available. The ALE-50 program cost is estimated at about $1.2 billion.

                        The Navy’s estimated RFCM cost for its F/A-18E/F aircraft is about
                        $2.6 billion. The Navy’s plan is to procure enough RFCM systems and spares
                        to equip and support 600 of its planned buy of 1,000 F/A-18E/F aircraft. For
                        600 F/A-18E/F aircraft, the number of decoys to be procured to meet
                        operational needs is 18,000. (These estimates predate the May 1997
                        decision of the Quadrennial Defense Review (QDR) to recommend a
                        reduction in the number of F/A-18E/Fs.)

                        The future RFCM decoy system is also being considered by the Air Force for
                        its B-1 aircraft, part of its F-15 fleet, and several other Air Force manned
                        and unmanned aircraft. If the Air Force buys the RFCM system for the B-1
                        and the F-15, which would use its existing onboard jammer instead of the
                        RFCM techniques generator, the estimated cost, including 9,107 decoys, is
                        about $574 million.


                        In contrast with the Air Force, which intends to use decoys to improve the
Current Navy Aircraft   survivability of its current aircraft, current Navy combat aircraft will be at
Will Not Be Provided    a comparative survivability disadvantage since they will not be provided
With Towed Decoys       with a decoy system. In particular, because F/A-18E/Fs will not be
                        replacing all of the C/D models in the Navy/Marine Corps inventory in the
                        foreseeable future, adding a towed decoy system to the F/A-18C/D




                        Page 3                     GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
B-272628




potentially offers the opportunity to save additional aircraft and aircrew’s
lives in the event of hostilities.

In the year 2010, more than 600 of the Navy’s tactical fighter inventory
objective of 1,263 aircraft will still be current generation fighters such as
the F/A-18C/D. This will be true even if F/A-18E/Fs are procured at the
Navy’s desired rates of as high as 60 per year. At the post-QDR suggested
rate of 48 per year, almost 50 percent of the current generation aircraft will
still be in the fleet in the year 2012.

DOD  and the Navy have done studies to determine whether towed decoys
could improve the survivability of the F/A-18C/D. DOD’s Joint Tactical
Electronic Warfare Study and an analysis conducted by the Center for
Naval Analyses concluded that the addition of a towed decoy system to the
F/A-18C/D would provide a greater increase in survivability for that
aircraft than any jammer, including the ASPJ.

In limited flight testing on the F/A-18C/D, the Navy demonstrated the
ALE-50 decoy could be deployed from either a wing station or the
centerline station of the aircraft. While the Navy acknowledges that towed
decoys can enhance aircraft survivability, it does not consider these flight
tests to have been successful because of the following suitability concerns.
According to the Navy (1) the tow line can come too close to the
horizontal tail or the trailing edge flap when deployed from a wing station,
making it unsafe or (2) the tow line can be burned off by the engine
exhaust or separated by abrasion if deployed from the centerline station.

The Navy’s report on the wing station testing stated that tow line
oscillation led to lines breaking on several flights, but did not state that the
decoy system was a flight safety risk nor that there was any contact with
the horizontal tail or flaps. Concerning the centerline station tests, several
tow lines were burned off or otherwise separated from the aircraft by
abrasion during maneuvering flights. A reinforced tow line later solved
these problems and the Navy is continuing testing on the F/A-18C/D from
the centerline station. Based on these test results, the Navy now intends to
deploy the ALE-50 decoy from the centerline of the fuselage of the
F/A-18E/F.

The Navy also maintains that even if the decoy could be successfully
deployed from the F/A-18C/D wing or centerline station, for actual
operations, it could not afford to trade a weapon or fuel tank on a wing or
centerline station for a towed decoy system. Further, the Navy considers



Page 4                      GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
                          B-272628




                          modification of the C/D model’s fuselage for internal carriage of the decoy
                          to be unaffordable due to volume, weight, power, and cooling constraints
                          that would have to be addressed.

                          The Air Force has modified a wing pylon to successfully deploy towed
                          decoys from the F-16’s wing while avoiding major aircraft modifications
                          and without sacrificing a weapons station or a fuel tank. The Navy,
                          however, has not done the technical engineering analyses to determine the
                          specific modifications necessary to accommodate a towed decoy on the
                          F/A-18C/D either from the wing or the centerline without affecting the
                          carriage capability unacceptably.


                          Congress has expressed concerns regarding F/A-18C/D survivability. The
Survivability of F/A-18   Report of the Senate Appropriations Committee on the National Defense
Aircraft Has Been a       Appropriations Act for Fiscal Year 1997 directed the Navy to report on the
Congressional             advantages and disadvantages of using various electronic warfare systems
                          to improve F/A-18C/D survivability. In addition, Congress provided
Concern                   $47.9 million in fiscal year 1997 funding not requested by DOD to buy 36
                          additional ASPJs for 3 carrier-deployed squadrons to meet contingency
                          needs.

                          The Navy could have addressed the congressional concern for C/D
                          survivability in the required report by including analysis of the
                          improvement offered by incorporating the ALE-50 and RFCM towed decoy
                          systems. In completing the required report, however, the Navy did not
                          include any analysis of survivability benefits from using towed decoys
                          because it maintains, as described above, that there are unacceptable
                          impacts associated with towed decoys on the F/A-18C/D.


                          In commenting on a draft of this report, DOD agreed that towed decoy
Agency Comments           systems could enhance aircraft survivability, but stated the Navy had
and Our Evaluation        conducted an engineering analysis that concluded any installation option
                          of a towed decoy on the F/A-18C/D has unacceptable operational and/or
                          safety of flight impacts. In response to our request for this analysis, the
                          Navy provided us with a paper discussing the feasibility of installing a
                          towed system on the F/A-18C/D. This paper concluded that the options
                          considered had risks or created operational concerns but did not conclude
                          that these options were unacceptable. Furthermore, the paper did not
                          consider all possible options.




                          Page 5                    GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
                 B-272628




                 With regard to the safety of flight issue, the Navy stated that the decoy or
                 towline might contact aircraft control surfaces such as the flaps or the
                 horizontal stabilizers if deployed from a wing station. The Navy’s summary
                 of wing station test results, however, does not show any evidence of such
                 contact. The Navy has expressed no concern about a safety of flight issue
                 when deploying the decoy along the aircraft’s centerline and continues to
                 fly test missions with the towed decoy, deploying it from a pod on the
                 centerline of an F/A-18D aircraft. Furthermore, the Navy intends to install
                 the system in the fuselage and deploy towed decoys from the centerline of
                 the E/F model aircraft. In addition, the Air Force incorporated the ALE-50
                 on to the F-16 without loss of a weapon station or fuel tank and without
                 having to undertake major aircraft modifications, demonstrating that it is
                 possible to adapt a towed decoy system to an existing aircraft without
                 creating unacceptable tactical impacts.

                 DOD  did not concur with the recommendations that were set forth in a
                 draft of this report. In the draft, we had suggested that (1) in preparing its
                 congressionally required report, DOD consider F/A-18C/D aircraft upgraded
                 with RFCM and ALE-50 towed decoy systems and (2) the Navy do the
                 necessary engineering analyses of the modifications needed to integrate
                 towed decoys into F/A-18C/D and other current Navy aircraft. DOD
                 completed the congressionally required report without implementing our
                 first draft recommendation. We continue to believe, however, that the
                 Navy needs to explore ways to improve the survivability of its current
                 aircraft and, therefore, should do a detailed engineering analysis of the
                 modifications needed to adapt the towed decoy to the F/A-18C/D. DOD’s
                 comments are reprinted as appendix I in this report.


                 We recommend that the Secretary of Defense direct the Secretary of the
Recommendation   Navy to make a detailed engineering analysis of the modifications needed
                 to adapt the towed decoy to the F/A-18C/D.


                 In light of the demonstrated improvement in survivability that analyses
Matters for      and test results indicate towed decoy systems can provide, and
Congressional    recognizing that in the year 2010 almost 50 percent of the Navy’s tactical
Consideration    fighter inventory will still be current generation fighter aircraft such as the
                 F/A-18C/D, Congress may wish to direct the Navy to find, as it has done for
                 its F/A-18E/F and the Air Force has done for the F-16, cost-effective ways
                 to improve the survivability of its current aircraft.




                 Page 6                     GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
              B-272628




              To accomplish our objective of determining whether towed decoys could
Scope and     improve survivability of Air Force and Navy aircraft, we examined DOD and
Methodology   contractor analyses of adding towed decoy systems and reviewed Air
              Force and Navy ALE-50 test results from testing on a variety of aircraft.
              We interviewed officials from the Office of the Secretary of Defense, the
              Navy, and the Air Force involved in the acquisition and testing processes
              of towed decoy systems. We also interviewed contractor personnel
              involved in the development, integration, and/or production of towed
              decoy systems.

              We performed our work at the Offices of the Secretaries of Defense, the
              Navy, and the Air Force; F-15, F-16, and B-1 System Program Offices at the
              Air Force Material Command, Wright-Patterson Air Force Base, Ohio;
              F/A-18 and Tactical Air Electronic Warfare Program Offices at the Program
              Executive Office for Naval Tactical Aviation, Naval Air Systems Command,
              Washington, D. C.; the 53rd Wing and Air Force Operational Test and
              Evaluation Detachment, Eglin Air Force Base, Florida; and selected
              contractor locations, including McDonnell-Douglas Aircraft,
              Lockheed-Martin, and Rockwell International.

              We performed our review from February 1996 to July 1997 in accordance
              with generally accepted government auditing standards.


              We are sending copies of this report to the Secretaries of Defense, the
              Navy, and the Air Force; the Director, Office of Management and Budget;
              and other congressional committees. We will make copies available to
              others upon request.

              Please contact me on (202) 512-2841, if you or your staff have any
              questions concerning this report. Major contributors to this report are
              listed in appendix II.




              Louis J. Rodrigues
              Director, Defense Acquisitions Issues



              Page 7                    GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
B-272628




Congressional Addressees

The Honorable Strom Thurmond
Chairman
The Honorable Carl Levin
Ranking Minority Member
Committee on Armed Services
United States Senate

The Honorable Ted Stevens
Chairman
The Honorable Daniel K. Inouye
Ranking Minority Member
Subcommittee on Defense
Committee on Appropriations
United States Senate

The Honorable Floyd D. Spence
Chairman
The Honorable Ronald V. Dellums
Ranking Minority Member
Committee on National Security
House of Representatives

The Honorable C.W. Bill Young
Chairman
The Honorable John P. Murtha
Ranking Minority Member
Subcommittee on National Security
Committee on Appropriations
House of Representatives

The Honorable Richard C. Shelby
Chairman
The Honorable J. Robert Kerrey
Vice Chairman
Select Committee on Intelligence
United States Senate




Page 8                     GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
B-272628




The Honorable Porter J. Goss
Chairman
The Honorable Norman D. Dicks
Ranking Minority Member
Permanent Select Committee on Intelligence
House of Representatives




Page 9                  GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
Appendix I

Comments From the Department of Defense


Note: GAO comments
supplementing those in the
report text appear at the
end of this appendix.




See comment 1.




See comment 2.



See comment 1.



See comment 3.




                             Page 10   GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
Appendix I
Comments From the Department of Defense




Page 11                     GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
                 Appendix I
                 Comments From the Department of Defense




See comment 1.




                 Page 12                     GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
                 Appendix I
                 Comments From the Department of Defense




See comment 2.




See comment 2.




See comment 2.


See comment 4.

See comment 3.




                 Page 13                     GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
               Appendix I
               Comments From the Department of Defense




               Following are our comments on the Department of Defense’s (DOD) letter
GAO Comments   dated May 5, 1997.

               1. Our draft report included references to the comparability of F/A-18E/F
               and C/D survivability, and it was provided to DOD for comment prior to the
               decision to produce the F/A-18E/F. As DOD states, this decision has now
               been made. Consequently, we have deleted references to the comparability
               of the F/A-18E/F and C/D models. The issue of F/A-18C/D survivability
               remains important, however, because E/F models will not replace all of
               the current C/D models in the inventory in the foreseeable future.

               2. Test results for towed decoys on the F/A-18C/D and other information
               provided by DOD and the Navy do not support DOD’s statements. The safety
               of flight issue, according to the Navy, arises from the concern that the
               decoy or towline might contact aircraft control surfaces such as the flaps
               or the horizontal stabilizers if deployed from a wing station. The Navy’s
               summary of wing station test results does not show any evidence of such
               contact. According to the test report, the Navy did find that aircraft
               vortices behind the wing created aerodynamic instability in the towline,
               but the report does not conclude that this potentially jeopardized aircraft
               flight safety. Additionally, the Navy has expressed no concern about a
               safety of flight issue when deploying the decoy along the aircraft’s
               centerline, and use of a reinforced towline appears to have eliminated the
               burnoff/abrasion problem. Thus, the Navy continues to fly test missions
               with the towed decoy, deploying it from a pod on the centerline of an
               F/A-18D aircraft, and intends to install the system in the fuselage and
               deploy towed decoys from the centerline of the E/F model aircraft. This
               evidence indicates that Navy concerns about a high degree of difficulty,
               and severe volume, weight, power, cooling, and aircraft aerodynamics
               issues associated with installing towed decoys may not be insurmountable.

               As for unacceptable tactical impacts associated with towed decoy
               installation, the Air Force has overcome this problem on the F-16, and we
               presume that the Navy may also be able to find an integration solution for
               the F/A-18C/D that avoids unacceptable tactical impacts if it continues to
               pursue alternatives. The Navy did not abandon towed decoy installation
               for the F/A-18E/F because of early problems with abrasion and heat
               breaking the towline. Instead, it pursued alternatives. The solutions for the
               F-16 and F/A-18E/F do not have to be the only alternatives considered for
               the F/A-18C/D.




               Page 14                     GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
Appendix I
Comments From the Department of Defense




3. The Navy and DOD did provide us with additional information intended
to bolster its broad assertion of unsuitability. However, the information
provided was not an “engineering analysis” (implying a technical
document of some depth), but is instead a rather superficial “installation
feasibility study” that while identifying risk areas associated with installing
the towed decoy on the F/A-18C/D does not conclude that all installation
options have unacceptable operational and/or safety of flight impacts.

4. According to the Navy’s feasibility study, 220 pounds is the weight of the
towed decoy system mounted in a pod. According to the same study, if the
system’s launch controller is mounted in the aircraft’s fuselage, the
bring-back weight is reduced by only 140 pounds. In any case, since
studies and test results indicate the ALE-50 system can provide significant
improvements in survivability, the Navy needs to determine whether loss
of a relatively small amount of bring-back weight is worth the increased
risk of losing aircraft to radar-guided missiles.




Page 15                     GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
Appendix II

Major Contributors to This Report


                        Michael Aiken
National Security and   Terrell Bishop
International Affairs   Paul Latta
Division, Washington,   Terry Parker
                        Charles Ward
D.C.




(707143)                Page 16          GAO/NSIAD-97-94 Electronic Warfare/Towed Decoy Systems
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