GAO

United States General Accounting Office

Report to Congressional Committees

June 1999 DEFENSE 

ACQUISITIONS

Progress of the

F/A-18E/F Engineering 

and Manufacturing 

Development Program

GAO/NSIAD-99-127

Page 1 GAO/NSIAD-99-127 Defense Acquisitions

United States General Accounting Office

Washington, D.C. 20548

National Security and

International Affairs Division

B-281419 Letter

June 15, 1999

Congressional Committees

As required by the National Defense Authorization Act for Fiscal Year 1999 

(P.L. 105-261), we reviewed the Navy’s F/A-18E/F developmental and 

operational test program. We presented the results of our review during 

testimony before the Subcommittee on Airland Forces, Senate Committee 

on Armed Services, on March 17, 1999.1

 This report supplements that 

testimony by providing additional data on the aircraft deficiencies 

identified during the test program and discusses our conclusions regarding 

the E/F’s progress toward achieving established performance, schedule, 

and cost goals. Specifically, we (1) determined the extent to which the 

aircraft is meeting performance requirements, (2) identified risks 

associated with proceeding into operational test and evaluation (OPEVAL) 

with unresolved deficiencies, and (3) identified potential cost increases 

and risks associated with approving the Navy’s request for multiyear 

funding for the program. The act also requires that we certify whether we 

had access to sufficient information to make informed judgments on the 

matters covered by this report.

Public Law 105-261 requires us to conduct annual reviews of the F/A-18E/F 

until the aircraft enters full-rate production. This report covers our first 

review under the act. During our next review, we will focus on determining 

whether beginning OPEVAL with a significant number of unresolved 

deficiencies will result in over reliance on modeling and simulation rather 

than actual flight testing. We will also determine whether test restrictions 

on the aircraft configuration or missions flown could invalidate OPEVAL 

results.

Results in Brief According to the Navy, the F/A-18E/F is meeting all performance 

requirements. We do not agree with the Navy’s assessment. The Navy 

based its assessment on the E model’s performance and assumed some 

improvements to the aircraft that have not yet been demonstrated. Without 

that assumption, the F model, which makes up over half of the E/F planned 

1

Defense Acquisitions: Progress of the F-22 and F/A-18E/F Engineering and Manufacturing Programs

(GAO/T-NSIAD-99-113, Mar. 17, 1999).
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buy, is not meeting the interdiction range requirement—a primary 

justification for the program. 

The Navy’s OPEVAL schedule, combined with unresolved aircraft 

deficiencies, could cause the E/F to fail OPEVAL. The Navy maintained its 

original schedule and started OPEVAL on May 27, 1999, even though 

completion of the development effort slipped from November 1998 to April 

1999. Because the Navy is maintaining its original OPEVAL schedule, the 

contractor has insufficient time to correct some critical deficiencies in the 

aircraft that, according to Navy criteria, should be corrected prior to 

OPEVAL. Department of Defense (DOD), Navy, and contractor personnel 

have stated that there is a medium risk that OPEVAL might find the E/F not 

operationally effective and/or suitable. Such a conclusion could result in a 

delay or postponement of the full-rate production decision and the need to 

conduct additional operational testing.

Corrections of some deficiencies have been shifted to later in the program. 

This will help the Navy stay within the congressionally mandated 

developmental cost cap; however, correcting these deficiencies will 

increase the procurement costs of the aircraft. Congress is considering the 

Navy’s request for multiyear procurement of the F/A-18E/F. A key criterion 

for obtaining congressional approval for multiyear procurement is design 

stability. Correction of some E/F deficiencies could result in contract 

modifications and design changes to the aircraft, which increases the risk 

associated with Congress’s approving the Navy’s multiyear procurement 

request for the E/F at this time. We recommend in this report that the 

Secretary of Defense defer multiyear funding for the E/F program until all 

corrections of deficiencies have been incorporated into the aircraft design 

and successfully tested. 

The Navy and the contractors gave us access to sufficient information to 

make informed judgments on the performance of the aircraft. With respect 

to program costs, we requested estimates to correct the deficiencies 

identified during the test program; however, the contractor told us that 

such estimates are not available. We also requested the procurement unit 

cost comparisons that the contractor and the Navy program office had 

prepared of procuring 548 E/Fs to procuring 548 C/D model aircraft. The 

program office declined to provide us those comparisons. 

Background The F/A-18E/F program began in 1992 to increase the operational 

capabilities of the current fleet of F/A-18 aircraft. The objectives of the 
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program are to provide improved capabilities over current F/A-18s in five 

key areas–range, payload, carrier recovery payload, growth capacity, and 

survivability. Congress capped the development effort at $4.88 billion (in 

fiscal year 1990 dollars) and directed that the E/F unit procurement cost 

not exceed 125 percent of current C/D model costs. 

The F/A-18E/F development flight test program began in February 1996. 

The Integrated Test Team, using five single-seat E models and two 2-seat F 

models, is conducting the tests. Two early operational assessments of the 

E/F aircraft, using wind tunnel data and analytical models, were made in 

early 1996 and 1997. Two operational assessments of the E/F aircraft, 

based on data obtained during test flights using the engineering and 

manufacturing development aircraft, were conducted in November 1997 

(OT-IIA) and in June through August 1998 (OT-IIB). The Navy’s Operational 

Test and Evaluation Force (OPTEVFOR) conducted these assessments. 

The Navy has contracted for 62 aircraft under three low-rate initial 

production contracts. The first seven of these aircraft will be used to 

conduct the next operational flight test phase of the program. That phase, 

OPEVAL, is to be conducted during May–November 1999. The OPEVAL 

results will be used to determine whether the E/F program should proceed 

into full-rate production in March 2000.

We reported in June 1996 that current F/A-18s are not as deficient as the 

Navy reported and that the F/A-18E/F would provide only a marginal 

improvement in capability over the older F/A-18s at a significantly greater 

cost.2

 We recommended that DOD reconsider its plan to buy the E/F and 

instead buy additional F/A-18C/Ds. DOD did not concur with our 

recommendation and continued to believe that procuring the E/F was the 

more cost-effective approach to modernizing the Navy’s tactical aviation 

fleet.

In March 1998 we reported that E/F flight test program officials had 

identified numerous deficiencies that if not corrected in time could affect 

the OPEVAL schedule or possibly cause the aircraft to have an 

unsuccessful operational test and evaluation.3

 We recommended that the 

Navy not be allowed to procure any additional E/Fs beyond the 12 initially 

2Navy Aviation: F/A-18E/F Will Provide Marginal Operational Improvement at High Cost

(GAO/NSIAD-96-98, June 18, 1996).

3

Navy Aviation: F/A-18E/F Development and Production Issues (GAO/NSIAD-98-61, Mar. 13, 1998).
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contracted for in March 1997 until the Navy demonstrated, through flight 

testing, that identified deficiencies had been corrected and incorporated 

into OPEVAL aircraft. DOD disagreed with that recommendation and 

stated that testing had not identified any specific deficiencies that would 

prevent the E/F from achieving an operationally effective level of 

performance. 

Extent to Which

F/A-18E/F Is Meeting 

Development 

Performance 

Requirements

The Navy is nearing completion of its F/A-18E/F development program. 

The development flight test program began in February 1996 and was 

completed in April 1999. During this phase of the program, the Navy 

conducted both developmental and some limited operational testing using 

the aircraft produced under the engineering and manufacturing 

development phase of the program. Based on the results of that testing, the 

Navy reports that the E/F is meeting all performance parameters. 

The Navy’s statements about the performance of the E/F reflect the 

performance of the single-seat E model aircraft, not the 2-seat F model. 

The second seat in the F model displaces fuel capacity, thereby reducing its 

range. The Navy’s assessment was also based on estimates of improved 

performance from anticipated changes to the aircraft, not all of which, 

according to the contractor, may come to fruition. If these values are not 

included in the performance estimates, the F model aircraft will be

33 nautical miles short of meeting the development interdiction range 

requirement of 390 nautical miles. This is significant because (1) the F 

model, which was originally planned to be used as a trainer aircraft and 

therefore made up only about 18 percent of the total buy, now will be used 

as an operational aircraft and makes up about 55 percent of the total buy 

and (2) increased range over the current C/D aircraft was critical to 

justifying the decision to buy the F/A-18E/F. The Navy formally reports that 

the F/A-18E/F will have over 40 percent more range than F/A-18Cs. 

However, initial E/F range predictions have declined as actual flight data is 

gathered and incorporated into range prediction models. Test data 

currently projects that the E model will have a range of 434 nautical miles, 

or about 15 percent greater than the 376 nautical mile range demonstrated 

by current F/A-18Cs. If the anticipated but not yet demonstrated range 

improvements are not included in the range estimates, the F/A-18E 

development interdiction range drops to 405 nautical miles, or about an

8-percent greater range than an F/A-18C. 

Also, the Navy’s assessment of the E/F’s performance does not consider the 

potential degradation of performance as a result of modifications to correct 
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unresolved deficiencies identified during the developmental and 

operational flight test programs. These deficiencies and their potential 

negative impacts relate to the aircraft’s combat range, payload, 

survivability, and ability to accommodate new, future systems. All of these 

areas were cited as improvements by the Navy when it justified the E/F 

program. 

Combat Range Potential solutions to problems found during the test program have 

resulted in a reduction in the E/F’s combat range. One of these problems, a 

condition described as “wing drop,” was observed early in 1996 during

F/A-18E/F development tests and was described as an unacceptable, 

uncommanded abrupt lateral roll that randomly occurred at the altitude 

and speed at which air-to-air combat maneuvers are expected to occur. In 

October 1998, the OPEVAL Preparedness Team reported that the 

anticipated fix to the problem, replacing solid wing fold fairings with 

porous fairings, significantly reduced, but did not totally eliminate, the 

frequency and severity of wing drop. However, the porous wing fold fairing 

has caused buffeting of the aircraft. The magnitude of the buffeting was 

described as severe enough to affect the pilots’ voices and could also mask 

an aircraft malfunction, particularly for aircrews not accustomed to the 

sensation. This buffeting was projected to reduce aircraft range. However, 

the actual range decrease is not yet known because resolution of the 

problem is still being worked on and program officials will not have a 

complete understanding of the impact of the wing drop design fix until 

operational testing is completed at the end of 1999. According to program 

officials, the final production fixes to wing drop may involve something 

other than the porous wing fold fairing.

Other range-related issues are associated with the Navy’s attempts to 

resolve design problems that had resulted in bombs colliding with each 

other or with the aircraft. To correct this problem, the Navy toed, or 

slanted, the inner wing pylons. However, that fix increased the drag on the 

aircraft and resulted in air loads on the pylons where the 480-gallon tanks 

would be carried that significantly exceed the load limit designed into the 

E/F wings in this area. If uncorrected, this deficiency would preclude the 

E/F from carrying 480-gallon external fuel tanks on each of the two inner 

wing stations specified for the interdiction mission and would prevent the 

aircraft from meeting its required range specification. The Navy is studying 

options for redesigning the pylons and their attachment to the aircraft to 

correct this problem. 
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Aircraft range will also be affected by the extent to which pilots use 

afterburner to compensate for deficiencies in the E/F’s climb, turn, and 

acceleration rates. Using afterburner to overcome these deficiencies will 

significantly increase fuel consumption and reduce mission range. 

Payload and Bringback The F/A-18E/F reportedly carries a 22-percent greater payload than existing 

F/A-18s. This increased payload is the result of the E/F’s two additional 

wing stations. However, development flight tests have revealed that the

E/F experiences noise and vibration under the wings and at the wing tips 

that could damage air-to-air missiles carried by the aircraft. The Navy is 

determining whether a redesign of the missiles will be necessary for them 

to be carried on the E/F. Additionally, excessive loads on the inner wing 

pylons have been caused by the closeness of these pylons to the aircraft 

fuselage and to the toeing of the pylons. Current plans are to restrict what 

can be carried on these pylons during OPEVAL until a fix is designed and 

tested. The restrictions would prohibit the E/F from carrying dual MK-83 

(1,000 pound) bombs on these pylons during OPEVAL, which would reduce 

the payload capacity for the interdiction mission. We were told that the 

aircraft could also have a problem landing on the carrier with unused 

weapons (bringback) because of the significant stress on these pylons. The 

Navy is still studying this issue and has not yet identified a final fix.

Survivability The Navy planned to improve F/A-18E/F survivability relative to existing

F/A-18s by reducing its susceptibility to detection and if detected the 

probability of being destroyed. Initial operational tests cite concerns about 

E/F survivability systems. While the specifics on E/F survivability are 

classified, the unclassified portions of the test reports identify concerns 

with the ALE-50 towed decoy and the ALR-67 radar warning receiver. The 

ALE-50 towed decoy is designed to improve F/A-18E/F survivability by 

attracting enemy missiles to the decoy and away from the aircraft. The line 

that tows the decoy has been burning off when it crosses the heat path of 

the engine when the engine is in afterburner. The problems relative to the 

ALR-67 radar warning receiver involve the receiver’s ability to provide 

accurate information on the direction of arrival of enemy threats. The 

Procurement Executive Officer for Tactical Aircraft identified E/F 

survivability issues as the major challenges facing the E/F program.

Growth Space In justifying the need for the F/A-18E/F, the Navy stated that it needed more 

space than was available on existing F/A-18s to accommodate additional 
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new systems without having to remove existing capability. The Navy 

reports that the F/A-18E/F will have 17 cubic feet of growth space. 

However, program documents show that only 5.46 cubic feet of that space 

will be usable for growth. We reported in 1996 that growth space was 

available within the C/D. The Navy’s F/A-18 upgrade road map shows that 

most of the upgrades planned for the E/F are also planned for installation 

on C/Ds, which demonstrates that the C/Ds have growth space.

Test Schedule and 

Unresolved 

Deficiencies Cause 

Risks to Successful 

OPEVAL

The objective of OPEVAL is to field test the E/F under realistic combat 

conditions to determine the aircraft’s operational effectiveness and 

suitability for use in combat by typical military users against threat forces 

and targets. For OPEVAL tests, the Navy plans to use productionrepresentative aircraft that are being produced under the first low-rate 

initial production contract. The OPEVAL results will be used to determine 

whether to proceed into full-rate production of the F/A-18E/F. Accordingly, 

the primary questions are whether the aircraft is ready to advance into 

OPEVAL and whether successful completion of that evaluation is highly 

probable. Test results indicate that the Navy faces significant challenges 

regarding each of those questions. 

F/A-18E/F development was scheduled to be completed by November 1998, 

with OPEVAL beginning in May 1999. That schedule would have provided 

time to correct deficiencies in the aircraft before their use during OPEVAL. 

However, additional test requirements, caused by the need to test 

corrections of deficiencies such as wing drop, have caused the completion 

of the development flight test program to slip to April 1999. As a result of 

the development program delay and the Navy’s decision to begin OPEVAL 

in May 1999 as originally scheduled, the contractor will not have time to 

correct some aircraft deficiencies that according to the Navy’s criteria 

should be fixed before OPEVAL. In that regard, the OPEVAL Preparedness 

Team, which comprises DOD, Navy, and contractor personnel, meets 

periodically to determine whether the E/F is ready for OPEVAL. On 

February 25, 1999, the team held its final meeting before the scheduled 

start of OPEVAL. At that meeting, the team concluded that 71 E/F 

deficiencies would not be corrected until after OPEVAL. The Navy’s 

criteria indicate that 23 of those deficiencies should be corrected prior to 

OPEVAL. These deficiencies consist of the problems associated with the 

ALE-50 towed decoy, the ALR-67 radar warning receiver, and the wing 

pylon loads. In addition, they include such things as vibration that damages 

ordnance, delamination of the composite surface layers of the horizontal 

tail, and problems with the nose landing gear tires and wheels during 
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catapult testing. The Preparedness Team concluded that there is a medium 

risk that the E/F will not successfully complete OPEVAL without first 

correcting these deficiencies. The Preparedness Team’s agreement to 

proceed into OPEVAL was based on the existence of correction plans to 

address these deficiencies. 

The Navy began OPEVAL on May 27, 1999. However, it plans to impose 

some operational limits on the aircraft during OPEVAL as a result of 

deficiencies that cannot be corrected prior to OPEVAL. For example, as 

previously discussed, the E/F will not be permitted to carry dual MK-83 

bombs because of the excessive air loads they put on the inner wing 

pylons. 

The E/F operational test team has completed two operational assessments, 

using aircraft produced during the EMD phase of the program, that relate 

to the potential for a successful OPEVAL. Those assessments, referred to 

as OT-IIA and OT-IIB, were conducted in November 1997 and from June 

through August 1998, respectively. Based on these assessments, the 

operational testers assigned a level of risk relative to a successful OPEVAL 

to each critical operational issue tested. Table 1 shows that the testers 

identified two operational effectiveness issues with significant risk

(air-to-air weapons and survivability) and six with moderate risk. 

Table 1: Critical Operational Issues

Source: Navy operational test reports.

The operational testers’ OT-IIB assessment identified 29 major deficiencies 

in the E/F. The deficiencies related to such things as the E/F’s ability to 

accelerate, turn, climb, and roll. Essentially, the E/F does not do as well in 

these areas as the F/A-18C aircraft. Additionally, the testers identified 

Critical operational issue OT-IIA risk OT-IIB risk

Air-to-air weapons Not assessed Significant

Survivability Significant Significant

Fighter escort Moderate Moderate

Combat air patrol Little or no risk Moderate

Air combat maneuvering Not assessed Moderate

Air-to-ground sensor performance Moderate Moderate

Air-to-ground weapons Moderate Moderate

Air-to-air sensor performance Moderate Moderate
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buffeting and lateral instability, or drift, as flying quality deficiencies. They 

also listed as major problems the ALE-50 towed decoy and the capability of 

the radar warning receiver to indicate the direction of oncoming threats. 

The specific deficiencies identified by the operational testers4

 are as 

follows:

• poor climb performance above 30,000 feet;

• low acceleration;

• airframe buffet;

• high angle of attack and agility and controllability;

• slow response to control inputs, slow loaded energy addition rate, and 

excessive speed loss during air combat maneuvering;

• tactically ineffective sustained turn rate;

• insufficient cooling capacity for seekers on air-to-air weapons;

• improper indication of direction of arrival of oncoming threat systems;

• damage to AIM-9 missile assemblies caused by wing tip environment;

• ALE-50 tow line burn-off in afterburner;

• difficulty maintaining lateral trim;

• under-wing environment damages aircraft stores;

• unsafe delivery of Rockeye bomb;

• aircraft radar deficiency;

• leading edge extension difficulties;

• inconsistent brake effectiveness;

• inadequate cooling capability of the fuel thermal management system; 

and

• Targeting Forward Looking Infrared Radar resolution and 

magnification. 

Appendix I describes each of these deficiencies and discusses their 

potential impact on the E/F’s ability to perform its missions.

The operational testers recommended that the E/F continue to be 

developed. They stated, however, that they based their recommendation 

on continued improvements in the E/F’s current maneuvering performance 

and the development of follow-on systems that they considered essential to 

get the operational effectiveness projected for the E/F. These 

improvements include such things as the Active Electronic Scanned Array 

radar, the Joint Helmet Mounted Cueing System, the AIM-9X missile, and 

the Integrated Defensive Electronic Countermeasure System.

4

Our list does not total 29 deficiencies because we combined closely related deficiencies. 
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In addition to the risks to OPEVAL identified by the operational testers and 

the OPEVAL Preparedness Team, the Program Risk Advisory Board, 

comprising Navy and contractor personnel, in its January 1999 assessment 

stated that there is a medium risk that OPEVAL might find the E/F not 

operationally effective and/or suitable, even if all development 

specification requirements are met. The Board stated that the consequence 

of this type of conclusion from OPEVAL could result in a delay or 

postponement of the full-rate production decision and the need to conduct 

additional operational testing. 

F/A-18E/F Costs and 

Request for Multiyear 

Funding 

The Navy reports that the F/A-18E/F development effort will be completed 

within the $4.88 billion (in fiscal year 1990 dollars) development cost 

ceiling established by Congress. However, as of the end of February 1999, 

71 identified deficiencies had not been corrected. Correction of these 

deficiencies will be accounted for as procurement, not development, costs. 

The contractor said that estimates of the costs of correcting these 71 

deficiencies are not available. In addition, Boeing has identified 99 

deficiencies in the aircraft that it believes it is not required to correct under 

the development contract. Estimates of the cost of correcting these 

deficiencies are also not available.

The Navy’s unit procurement cost estimate for the E/F assumes that it will 

accrue $1.3 billion of savings if Congress approves the Navy’s request for 

multiyear funding as part of the fiscal year 2000 authorization and 

appropriation process. Approval of such funding has historically depended 

on the ability to obtain significant savings, a stable system design, an 

adequately validated requirement, and a commitment to stable funding 

over the life of the contract. The concerns raised within DOD about the 

uncertainty that the E/F will successfully complete OPEVAL and the 

number of unresolved issues, like the final solution to wing drop and 

buffeting and the inner wing pylon load concerns that could require design 

changes to the aircraft, increase the risk associated with congressional 

approval of the E/F multiyear funding request at this time.

Conclusions and 

Recommendation

The F/A-18F model is not meeting its interdiction range requirement–a 

primary justification for the program. The aircraft has some critical 

deficiencies that, notwithstanding Navy criteria to the contrary, will not be 

corrected until after OPEVAL. Correcting these deficiencies later in the 

program will enable the Navy to remain within the development cost cap 
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but will increase the unit procurement cost of the aircraft. The impact of 

correcting these deficiencies on the cost and final design of the aircraft are 

factors critical to Congress’ decision on whether to approve the Navy’s 

pending request for multiyear procurement of the E/F aircraft.

Given the uncertainty surrounding the F/A-18E/F’s final design and the 

Navy’s intention not to correct all deficiencies and test those corrections as 

part of OPEVAL, we recommend that the Secretary of Defense defer 

multiyear funding for the E/F program until all corrections of deficiencies 

have been incorporated into the aircraft design and successfully tested.

Agency Comments and 

Our Evaluation

In its written comments on our draft report DOD did not agree with our 

recommendation. DOD stated that no deficiencies have been identified 

that would require a major redesign of the aircraft or are serious enough to 

warrant not awarding a multiyear contract. To take this position, DOD is 

assuming that all major deficiencies will be corrected with minimum 

impact on aircraft design, cost, or schedule. Specifically, DOD stated that 

although the aircraft will have 84 major deficiencies when it enters 

OPEVAL, 50 of them have a road map for solutions and funding. This 

indicates that the Navy has a plan in place to correct the deficiencies, but 

the Navy did not specify the dates for incorporating and testing the 

corrections. We continue to believe that the deficiencies should be 

corrected and validated through flight testing before the program is 

approved for multiyear funding. Therefore, we reaffirm our 

recommendation.

DOD also took issue with our statement that the F/A-18F is not meeting its 

interdiction range requirement. DOD stated that someone unfamiliar with 

the E/F program might assume this represents a serious deficiency in the 

program, which DOD said is not the case. The purpose of our statement 

was to put into perspective Navy statements that the E/F program is 

meeting all performance requirements. DOD’s comments affirm that the F 

model is not meeting the interdiction range requirement, but by a tactically 

insignificant amount. Thus, the issue has evolved into differing 

perspectives on the magnitude of the F model’s range deficiency.

We reported that the range of the two-seat F model aircraft is 33 nautical 

miles short of the interdiction range requirement, and DOD stated that the 

deficiency is only 3 nautical miles. The essence of the difference between 

our conclusion and the Navy’s relates to (1) whether projected but not yet 

demonstrated and approved range improvements are included in the 
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projections and (2) what development engine is used to make the 

projections. The interdiction range deficiency that we reported reflects 

data that Boeing provided us. The data identified various planned range 

improvement efforts. The planned improvements included reducing 

aircraft weight, increasing the amount of internal fuel, and using a more 

efficient engine. Boeing officials stated that since these planned 

improvements had not yet been demonstrated and approved, they were not 

included in their range calculations. For the same reason, the planned 

improvements and their potential effect on E/F range were not included in 

our reported range figures.

The Navy range projections include the projected improvements and are 

based on a better performing engine than the one used in the contractor’s 

estimates. In its comments, DOD stated that while Boeing is required by 

the development contract to use minimum new engine performance in its 

calculations, the Navy elected to use the Full Performance Qualification 

(FPQ) engine in its projections. The FPQ engine is a better performing, 

more efficient engine that will get greater range than the one used in 

Boeing’s range calculations. Using the FPQ engine, the Navy estimates the 

interdiction range shortfall of the F model aircraft to be 3 nautical miles. 

Our concerns about the Navy’s use of the FPQ engine in its range 

projections stem from the fact that while Navy officials said that the engine 

had successfully completed all demonstration, analysis, and testing 

required for full qualification, the FPQ report, dated December 28, 1998, 

identified a number of exceptions to full performance qualifications. 

Specifically, the report stated that a number of engine parts have not yet 

met life limits and redesign efforts are underway. Other engine redesign 

efforts identified in the report include addressing the fact that the engine 

exceeds specified weight limits, is experiencing engine stalls, and has not 

demonstrated required reliability. We did not attempt to update the status 

of the engine redesign efforts and their impact on the E/F’s range to further 

reconcile the difference between our and the Navy’s E/F range projections 

because such a reconciliation is not warranted at this stage of the E/F 

program. OPEVAL of the F/A-18E/F began on May 27, 1999. The flight 

demonstrated range of the E/F under realistic combat conditions will 

provide a more meaningful assessment of the aircraft’s range than any 

mathematical calculations that either we or the Navy might make outside 

of OPEVAL. 

DOD disagreed with statements in our report that the number and type of 

F/A-18E/F deficiencies that testing has identified pose a significant risk to 

passing OPEVAL. DOD stated that the 84 unresolved major deficiencies 
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that the E/F will have when it enters OPEVAL are significantly fewer than 

the number of unresolved deficiencies that the earlier F/A-18A/B model had 

when it entered OPEVAL and pose an acceptable level of risk to 

successfully completing OPEVAL. We did not compare the number of 

unresolved F/A-18A/B deficiencies with unresolved E/F deficiencies 

because the F/A-18A/B aircraft was a new aircraft development program 

and the E/F is a modification program. Given that distinction, it is 

understandable that the A/B aircraft program would have had more 

deficiencies. However, the readiness of the aircraft to begin and 

successfully complete OPEVAL is not exclusively dependent upon the 

number of deficiencies, but rather on the significance of the deficiencies 

and the status of their resolution.

Regarding the significance and status of the deficiencies, DOD stated that 

the Navy is following the deficiency resolution process defined in 

SECNAVINST 5000.2. This Navy instruction provides the criteria that must 

be met for an aircraft to be certified as being ready for OPEVAL. One of the 

criteria states that “for aircraft programs, there are no unresolved Board of 

Inspection and Survey Part I (*) or Part I (**) deficiencies.5

” Further 

elaboration of this point is contained in the Board of Inspection and 

Survey’s implementing instruction (INSURVINST 13100.1E), which states 

that “in general, systems with Part I (**) and Part I (*) deficiencies will not 

be recommended for OPEVAL.” We conservatively applied these criteria 

and included only those deficiencies identified as Part I (**) in our report. 

DOD’s comments on our draft report did not segregate the 84 E/F major 

deficiencies into these deficiency categories. In addition, the Navy 

considers 50 of the 84 deficiencies to be resolved based on the existence of 

a correction plan. The remaining 34 major deficiencies apparently have not 

yet been resolved to that point. We believe DOD’s comments validate the 

OPEVAL Preparedness Team’s conclusion stated in our report that 

beginning OPEVAL without correcting these deficiencies results in a 

medium risk that the E/F will not successfully complete OPEVAL. 

Separate from DOD’s comments, the Navy provided information on its 

efforts to correct some of the major unresolved deficiencies identified 

during testing of the E/F aircraft. Essentially, the Navy commented on its 

plans to incorporate corrections of these unresolved deficiencies. 

5

Part I (**) deficiencies are defined as those where there is a high probability that the deficiency will 

cause aircraft control loss, equipment destruction, or injury. Part I (*) deficiencies are defined as those 

that would cause excessive operator compensation to accomplish the primary or alternate mission.
B-281419

Page 14 GAO/NSIAD-99-127 Defense Acquisitions

However, those plans do not alter our position that multiyear funding 

should not be approved for the F/A-18E/F program until these corrections 

of deficiencies have been incorporated into the aircraft and successfully 

tested. 

We conducted our review from September 1998 through June 1999 in 

accordance with generally accepted auditing standards. Our objectives, 

scope, and methodology are included in appendix II. DOD’s comments are 

reprinted in appendix III.

We are sending copies of this report to the Honorable William Cohen, 

Secretary of Defense; the Honorable Richard Danzig, Secretary of the Navy; 

and the Honorable Jacob Lew, Director, Office of Management and Budget. 

Copies will also be made available to others on request. 

Please contact me at (202) 512-4841 if you or your staff have any questions 

concerning this report. The major contributors to this report were Steven 

Kuhta, Jerry Clark, Stacy Edwards, and Charles Burgess.

Louis J. Rodrigues

Director, Defense Acquisitions Issues
B-281419

Page 15 GAO/NSIAD-99-127 Defense Acquisitions

List of Congressional Committees

The Honorable John W. Warner

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 Ike Skelton

Ranking Minority Member

Committee on Armed Services

House of Representatives

The Honorable Jerry Lewis

Chairman

The Honorable John P. Murtha

Ranking Minority Member

Subcommittee on Defense

Committee on Appropriations

House of Representatives
Page 16 GAO/NSIAD-99-127 Defense Acquisitions

Contents

Letter 1

Appendix I

Major F/A-18E/F 

Deficiencies Identified 

During OT-IIB

18

Appendix II

Objectives, Scope, and 

Methodology

22

Appendix III

Comments From the 

Department of Defense

24

Tables Table 1: Critical Operational Issues 8

Abbreviations

DOD Department of Defense

FPQ Full Performance Qualification

OPEVAL operational test and evaluation

OPTEVFOR Operational Test and Evaluation Force
Page 17 GAO/NSIAD-99-127 Defense Acquisitions
Page 18 GAO/NSIAD-99-127 Defense Acquisitions

Appendix I

Major F/A-18E/F Deficiencies Identified 

During OT-IIB ApenIdxi

The OT-IIB report listed 29 major deficiencies in the F/A-18E/F. The 

following discusses the deficiencies and their impact on the aircraft’s 

ability to perform its missions. Our list does not total 29 deficiencies 

because we combined closely related deficiencies. We extracted the 

information from unclassified deficiency reports prepared by the 

Integrated Test Team. 

Poor climb performance above 30,000 feet. The F/A-18E/F’s best climb 

performance was in the low 30,000-foot range, with intermediate power. 

Although higher altitudes may have been possible, the climb rate was too 

slow to be useful in most tactical scenarios. Performance predictions 

indicate that combat and tactical ceilings for the newer F/A-18Cs (Lot XIX) 

are greater than that of the F/A-18Es when the aircraft are similarly loaded 

with weapons and fuel tanks. The E/Fs low tactical ceiling reduced the 

mission effectiveness of the aircraft when in the fighter escort 

configuration against high, fast-flying enemy aircraft by limiting the regions 

where the E/F could effectively launch its air-to-air missiles.

Low acceleration. The E/F’s maximum level flight airspeed was 

determined to be less than both the F/A-18C and other threat aircraft in 

similar fighter configurations at all investigated altitudes. This deficiency 

reduced the E/F’s effectiveness against high, fast-flying aircraft and 

provided insufficient airspeed when the E/F was attempting to exit a 

combat situation.

Airframe buffet. The magnitude of buffet has been described as moderate 

to heavy. At higher levels, the aircraft shakes to the extent that the headsup displays appear to vibrate. The displays remain readable but are blurred 

slightly and legibility is somewhat degraded. During some turns at subsonic 

speed and low altitude, buffet forces the pilot to divert significant attention 

to maintaining the desired flight path, and combat effectiveness decreases 

as a result. During some landings, buffet has been heavy enough to be 

interpreted as an aircraft malfunction. Heavy airframe buffet during 

catapult launches would result in dramatic increases in the required windover-deck for high gross weights, thereby restricting operational capability.

Inadequate high angle of attack agility and controllability. The time 

required to reverse the aircraft from a nose high to a nose low position took 

significantly longer than desired and prevented the aircraft from 

dominating aggressive positions during fights. The aircraft frequently 

gained the offensive advantage but lost the advantage during the reversal 
Appendix I

Major F/A-18E/F Deficiencies Identified 

During OT-IIB

Page 19 GAO/NSIAD-99-127 Defense Acquisitions

from nose high to nose low. As a result, mission effectiveness would be 

reduced and aircraft loss is possible.

Slow response to control inputs, slow loaded energy addition rate, and 

excessive speed loss during air combat maneuvering. Air combat 

maneuvering placed the aircraft in the high angle of attack/low airspeed 

flight regime. To maintain a tactical advantage, the pilots tried to increase 

the airspeed by reducing the angle of attack. Pilots noted that reducing the 

angle of attack to the desired level took an unacceptable amount of time in 

regaining airspeed. As a result of the loss of airspeed, the pilots would lose 

the advantage during air combat maneuvering, resulting in reduced tactical 

utility and possible loss of aircraft and aircrew during actual air combat.

Tactically ineffective sustained turn rate. The current performance data 

indicate that the aircraft might not meet the F/A-18E specification 

requirement in this area. This would result in a potential reduction in 

performance during combat turns.

Insufficient cooling capacity for seekers on air-to-air weapons. The current 

nitrogen bottle will not cool the seekers on air-to-air weapons for the 

duration of a combat air patrol mission. It is possible to delay cooling the 

missiles until the aircraft enters a threat area, but this is operationally 

unacceptable. The bottles will have to be changed after every flight 

because of their short life. However, changing the bottles requires the E/F’s 

wings to be unfolded on the carrier deck. This would delay deck 

operations and the availability of the aircraft to conduct its next flight 

(carrier cycle time).

Improper indication of direction of arrival of oncoming threat systems. 

The ALR-67 (V)3 radar warning receiver’s left/right discrimination is 

inadequate. While evaluating air-to-air tactics during one-on-one 

intercepts, the radar warning receiver angle of arrival at times significantly 

disagreed with actual target locations. On a number of occasions, the 

actual target location was on one side of the aircraft nose, and the 

displayed direction of arrival was on the other side. The difference was, at 

times, substantial. Poor radar warning receiver direction of arrival 

information would result in degradation of situational awareness and poor 

aircrew defensive reaction. This would lead to loss of tactical advantage 

and might result in loss of aircraft and aircrew.

Damage to AIM-9 missile assemblies caused by wing tip environment. 

Structural failure of AIM-9 Sidewinder hanger on the wing tip stations 
Appendix I

Major F/A-18E/F Deficiencies Identified 

During OT-IIB

Page 20 GAO/NSIAD-99-127 Defense Acquisitions

could result in damage to the missile and launcher or an increase in 

required aircraft maintenance. If undetected, the missile damage would 

result in hazardous separation and/or decreased missile effectiveness. 

AIM-9 missile hanger failure might be the result of the F/A-18E/F’s severe 

wing tip environment. 

ALE-50 tow line burn-off in afterburner. During in-flight evaluation of the 

ALE-50, decoys and associated towlines were severed when engine 

afterburners were engaged. Towlines typically failed within seconds of 

afterburner initiation, which will occur during missile defense and air 

combat maneuvering. This deficiency would result in the loss of active 

electronic countermeasures protection and would directly increase the 

threat to aircraft and crew during enemy missile attacks.

Difficulty in maintaining lateral trim. The aircraft did not readily maintain 

lateral trim without frequent pilot inputs. The failure of the airplane to 

maintain lateral trim was not associated with any particular maneuver but 

rather a variety of maneuvers throughout the flight envelope. This 

condition would significantly increase the pilot’s workload, distracting him/

her and severely degrading the performance of more critical mission tasks.

Under-wing environment damages aircraft stores. Damage has been 

discovered on numerous stores (attachments and ordnance) carried 

beneath the aircraft’s wings. The damage is the result of the noise and 

vibration beneath the wings. Failure of items carried underneath the wings 

could result in loss of or damage to the aircraft and/or loss of mission 

capability.

Unsafe delivery of Rockeye bomb. Clearance was insufficient when the 

Rockeye bomb was carried on the inboard wing station and the Tactical 

Forward Looking Infrared Radar was carried on the aircraft’s fuselage 

station. This close proximity is not compatible with safe separation 

requirements.

Aircraft radar deficiency. The APG-73 radar, new to the aircraft, was slow 

to lock onto a target during air combat maneuvering. Delayed and 

unreliable radar acquisitions would result in lost first-shot opportunities 

and in delayed time to kill, which reduces tactical performance and 

survivability.

Leading edge extension difficulties. Footing on the leading edge extension 

was not secure during cockpit ingress/egress. As a result of the small 
Appendix I

Major F/A-18E/F Deficiencies Identified 

During OT-IIB

Page 21 GAO/NSIAD-99-127 Defense Acquisitions

walkway and steep slope of the leading edge extension and inadequate 

traction, the aircrew or maintenance personnel could slip off the aircraft 

during cockpit ingress/egress and experience serious injury. 

Inconsistent brake effectiveness. Braking performance was noticeably 

inadequate during landings by aircraft returning to the carrier without 

weapons. The primary turnoff was missed and the secondary turnoff was 

narrowly made. Poor, degraded, or unpredictable braking performance 

would result in longer landing rollout, turnoff overshoot, and decreased 

braking sensitivity for ground handling/positioning. Inability to stop the 

aircraft reliably could result in an aborted landing attempt or injury to 

ground personnel during aircraft positioning on the flight line or flight 

deck.

Inadequate cooling capability of the fuel thermal management system. 

During several missions flown on hot days, test aircraft experienced “FUEL 

HOT” cautions either shortly after takeoff or prior to mission completion. 

The “FUEL HOT” conditions resulted in the inability of the fuel to cool the 

aircraft’s fluids that cool the radar and other aircraft systems. In-flight 

“FUEL HOT” cautions could result in premature mission abort, degraded 

cooling of accessories such as the radar and hydraulics, and reduced 

reliability/life of engine management systems. 

Targeting Forward Looking Infrared Radar deficiencies. Aircrew 

determined that as a result of resolution and magnification deficiencies 

with the aircraft’s Targeting Forward Looking Infrared Radar, they could 

not classify air-to-air and air-to-ground targets. Aircrew would have 

difficulty quickly and accurately designating a discrete target. Additionally, 

target identification would require excessive head-down time, during 

which the weapon system operator would be unable to scan the electronic 

warfare display and look outside the aircraft for potential threats.
Page 22 GAO/NSIAD-99-127 Defense Acquisitions

Appendix II

Objectives, Scope, and Methodology ApendxIi

Our objectives were to (1) determine the extent to which the F/A-18E/F is 

meeting performance requirements, (2) identify risks associated with 

proceeding into operational test and evaluation (OPEVAL) with unresolved 

deficiencies, and (3) identify potential cost increases and risks associated 

with approving the Navy’s request for multiyear funding for the program.

To determine whether the program was meeting performance 

requirements, we compared contractor and program management 

performance measurements and projections with the five key performance 

improvements over current F/A-18s that the F/A-18E/F was intended to 

provide. We also reviewed contractor and Navy comparisons of the 

aircraft’s current performance relative to the development contract 

specifications and to key performance parameters established in the Navy’s 

F/A-18E/F Operational Requirements Document. Additionally, we 

reviewed reports on the limited operational assessments conducted in 

November 1997 (OT-IIA) and from June through August 1998 (OT-IIB) to 

identify the measured performance of the F/A-18E/F relative to numerous 

critical operational issues and to existing F/A-18s. 

We also interviewed officials in the Navy’s Operational Test and Evaluation 

Force responsible for conducting the operational assessments, including 

the test pilots who flew the operational tests, to obtain their assessment of 

the aircraft’s current and potential performance as well as its performance 

compared to current F/A-18s. 

To identify risks associated with proceeding into OPEVAL with unresolved 

deficiencies, we reviewed documents prepared by the Program Risk 

Advisory Board and the OPEVAL Preparedness Team. These documents 

and interviews identified operational performance deficiencies that the 

operational testers, the Advisory Board, and the OPEVAL Preparedness 

Team concluded could adversely affect the F/A-18E/F’s probability of 

successfully completing OPEVAL, which is to be conducted from May 

through November 1999. 

To identify potential cost increases and risks associated with approving the 

Navy’s request for multiyear funding for the program, we analyzed reports 

and other program documents prepared by contractor and Navy officials 

responsible for tracking program costs. Regarding the multiyear funding 

request, we analyzed the Navy and the contractor lists of aircraft 

deficiencies and assessed their impact relative to the criteria that must be 

met to obtain multiyear funding—significant savings, a stable system 
Appendix II

Objectives, Scope, and Methodology

Page 23 GAO/NSIAD-99-127 Defense Acquisitions

design, an adequately validated requirement, and a commitment to stable 

funding over the life of the contract. 
Page 24 GAO/NSIAD-99-127 Defense Acquisitions

Appendix III

Comments From the Department of Defense ApenIdxi

Note: GAO’s comment 

supplementing those in the 

report text appear at the end 

of this appendix.

See comment 1.
Appendix III

Comments From the Department of Defense

Page 25 GAO/NSIAD-99-127 Defense Acquisitions
Appendix III

Comments From the Department of Defense

Page 26 GAO/NSIAD-99-127 Defense Acquisitions
Appendix III

Comments From the Department of Defense

Page 27 GAO/NSIAD-99-127 Defense Acquisitions

The following is our comment on the Department of Defense’s (DOD) letter 

dated May 12, 1999.

GAO Comments 1. DOD’s statement that a separate interdiction range requirement for the 

F/A-18F was never included in the Operational Requirements Document is 

not accurate. An interdiction range requirement of 390 nautical miles for 

both the E and F model aircraft was included in the final Operational 

Requirements Document dated April 1, 1997.

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