F-35 Joint Strike Fighter: Restructuring Has Improved the Program, but Affordability Challenges and Other Risks Remain
Published: 2013-06-19T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: The F-35 Lightning II, the Joint Strike Fighter, is DODs most costly and ambitious aircraft acquisition. The program is developing and fielding three aircraft variants for the Air Force, Navy, Marine Corps, and eight international partners. The F-35 is critical to long-term recapitalization plans as it is intended to replace hundreds of existing aircraft. This will require a long-term sustained funding commitment. Total U.S. investment is nearing $400 billion to develop and procure 2,457 aircraft through 2037. Fifty-two aircraft have been delivered through 2012. The F-35 program has been extensively restructured over the last 3 years to address prior cost, schedule, and performance problems. DOD approved a new acquisition program baseline in March 2012.
This testimony is largely based on GAOs recently released report, G AO-13-309. This testimony discusses (1) progress the F-35 program made in 2012, and (2) major risks that program faces going forward. GAOs work included analyses of a wide range of program documents and interviews with defense and contractor officials.
section_title: What GAO Found
paragraphs: The new F-35 acquisition baseline reflects positive restructuring actions taken by the Department of Defense (DOD) since 2010, including more time and funding for development and deferred procurement of more than 400 aircraft to future years. Overall, the program progressed on several fronts during 2012 to further improve the current outlook. The program achieved 7 of 10 key management objectives and made substantial progress on one other. Objectives on aircraft deliveries and a corrective management plan were not met. The F-35 development test program substantially met expectations with some revisions to flight test plans and made considerable progress addressing key technical risks. Software management practices and some output measures improved, although deliveries to test continued to lag behind plans. Manufacturing and supply processes also improved--indicators such as factory throughput, labor efficiency, and quality measures were positive. While initial F-35 production overran target costs and delivered aircraft late, the latest data shows labor hours decreasing and deliveries accelerating.
Going forward, the F-35 program still faces considerable challenges and risks. Ensuring that the F-35 is affordable and can be bought in the quantities and time required by the warfighter will be a paramount concern to the Congress, DOD, and international partners. With more austere budgets looming, F-35 acquisition funding requirements average $12.6 billion annually through 2037 (see below). Once fielded, the projected costs of sustaining the F-35 fleet have been deemed unaffordable by DOD officials; efforts to reduce these costs are underway. Software integration and test will be challenging as many complex tasks remain to enable full warfighting capability. The program is also incurring substantial costs for rework-currently projected at $1.7 billion over 10 years of production-to fix problems discovered during testing. With about two-thirds of development testing still to go, additional changes to design and manufacturing are likely. As a result, the program continues to incur financial risk from its plan to procure 289 aircraft for $57.8 billion before completing development flight testing.
section_title: What GAO Recommends
paragraphs: GAOs prior reviews of the F-35 made numerous recommendations to help reduce risk and improve outcomes. DOD has implemented those recommendations to varying degrees.

section_title: Letter
paragraphs: Thank you for the opportunity to discuss our work on the F-35 Lightning II,  also known as the Joint Strike Fighter (JSF). At a cost approaching $400  billion, the F-35 is the Department of Defense’s (DOD) most costly and  ambitious acquisition program. The program is developing and fielding  three aircraft variants for the Air Force, Navy, and Marine Corps and eight  international partners. The F-35 is the linchpin of U.S. and partner plans  to replace existing fighters and support future combat operations. In a  time of austere federal budgets, DOD continues to project significant  long-term sustained funding requirements for the F-35 while, at the same  time, pursuing several other expensive systems. Over the past 3 years,  DOD has extensively restructured the F-35 program to address poor cost,  schedule, and performance outcomes. Most recently, in March 2012,  DOD established a new, more realistic, F-35 acquisition program baseline  that reflects increased costs, longer schedule times, and deferred  procurement of 410 aircraft to the future. Appendix I tracks program  baseline changes since the start of system development in 2001.
We have reported annually on F-35 issues since 2005. My testimony  today is largely based on the results of our latest review, and addresses  (1) the progress the F-35 program made in 2012 and (2) the major risks  that the program faces going forward. To conduct our work, we reviewed  program status reports and briefings, management objectives, test plans  and results, and internal DOD analyses with a focus on accomplishments  in calendar year 2012 compared to original plans for that year. We  obtained manufacturing data and cumulative outputs from the start of  production in 2007 through the end of 2012, and discussed development  and production issues and results to date, future expansion plans, and  improvement efforts with DOD, F-35 program, and contractor officials. We  toured the aircraft manufacturing plant, obtained production and supply  performance indicators, identified cumulative and projected engineering  changes, and discussed factory improvements and management controls  with members of the contractor’s work force and DOD plant  representatives. We evaluated DOD’s restructuring actions and impacts  on the program, tracked cost and schedule changes from program start to  the March 2012 baseline, and determined factors driving the changes.  We obtained current projections of acquisition funding needs through  2037 and estimated life cycle sustainment funding requirements. We  conducted this work in accordance with generally accepted government  auditing standards.
subsections: section_title: F-35 Program Performance Improved in 2012
paragraphs: The F-35 program made progress in 2012 on several fronts. The program  met or substantially met most of its key management and development  testing objectives for the year. We also found that the program made  progress in addressing key technical risks, as well as improving software  management, manufacturing, and supply processes.
subsections: section_title: Most Management and Development Testing Objectives Were Achieved
paragraphs: The F-35 program met or substantially met most of its key management  objectives established for calendar year 2012. The program office  annually establishes major management objectives that it wants to  achieve in the upcoming year. The F-35 program achieved 7 of its 10  primary objectives in 2012. Those included, among other things, the  completion of development testing on early increments of software, the  beginning of lab testing for both variations of the helmet mounted display,  the beginning of pilot training for two aircraft variants, and the completion  of negotiations on the restructured development contract. Although the  program did not complete its software block 3 critical design review as  planned in 2012, it did successfully complete its block 3 preliminary  design review in November 2012 and the critical design review in late  January 2013. The program did not meet its objectives to (1) deliver 40  production aircraft in 2012 and (2) receive approval from the Defense  Contract Management Agency of the contractor’s plan for correcting  deficiencies in its system for tracking and reporting cost and schedule  progress.
The F-35 development flight test program also substantially met 2012  expectations with some revisions to original plans. The program  exceeded its planned number of flights by 18 percent, although it fell short  of its plan in terms of test points flown by about 3 percent, suggesting  that the flights flown were not as productive as expected. Test officials  had to make several adjustments to plans during the year due to  operating and performance limitations with aircraft and late releases of  software to test. As a result, none of the three variants completed all of  their planned 2012 baseline points, but the test team was able to add and  complete some test points that had been planned for future years. Testing  accomplished on each of the aircraft variants in 2012 included:
Conventional takeoff and landing variant (F-35A)—accomplished high  angle of attack testing, initial weapons separation, engine air start,  expansion of the airspeed and altitude envelopes, and evaluated  flying qualities with internal and external weapons.
Short takeoff and vertical landing variant (F-35B)—accomplished the  first weapons release, engine air start tests, fuel dump operations,  flight envelope expansion with weapons loaded, radar signature  testing, and tested re-design air inlet doors for vertical lift operations.
Carrier suitable variant (F-35C)—conducted speed and altitude range  verification and flights with external weapons, prepared for simulated  carrier landings, and conducted shore-based tests of a redesigned  arresting hook.
section_title: Progress Made in Addressing Key Technical Risks
paragraphs: In 2012, the F-35 program also made considerable progress in  addressing four areas of technical risk that if left unaddressed could  substantially degrade the F-35’s capabilities and mission effectiveness.  However, additional work remains to fully address those risks. These risk  areas and the actions taken in 2012 are discussed below:  1.  Helmet mounted display (HMD)—DOD continued to address technical  issues with the HMD system. The original helmet mounted display,  integral to mission systems, encountered significant technical  deficiencies and did not meet warfighter requirements. The program is  pursuing a dual path by developing a second, less capable helmet  while working to fix the first helmet design. In 2012, DOD began  dedicated ground and flight testing to address these issues. Both  variations of the helmet mounted display are being evaluated and  program and contractor officials told us that they have increased  confidence that the helmet deficiencies will be fixed. DOD may make  a decision in 2013 as to which helmet to procure.  2.  Autonomic Logistics Information System (ALIS)—ALIS is an important  tool to predict and diagnose aircraft maintenance and supply issues.  ALIS systems with limited capability are in use at training and testing  locations. More capable versions of ALIS are being developed and  program and contractor officials believe that the program is on track to  fix previously identified shortcomings and field the fully capable  system in 2015. Limited progress was made in 2012 on developing a  smaller, transportable version needed to support unit level  deployments to operating locations.  3.  Arresting hook system—The carrier variant arresting hook system  was redesigned after the original hook was found to be deficient,  which prevented active carrier trials. The program accomplished risk  reduction testing of a redesigned hook point to inform this new design.  The preliminary design review was conducted in August 2012 and the  critical design review in February 2013. Flight testing of the  redesigned system is slated for late 2013.  4.  Structural durability—Over time, testing has discovered bulkhead and  rib cracks on the aircraft. Structural and durability testing to verify that  all three variants can achieve their expected life and identify life- limited parts was completed in 2012. The program is testing some  redesigned structures and planning other modifications. Officials plan  to retrofit and test a production aircraft already built and make  changes to the production line for subsequent aircraft. Current  projections show the aircraft and modifications remain within weight  targets.
section_title: Software Management and Output Improved
paragraphs: In 2012, the F-35 aircraft contractor and program office took steps to  improve the program’s software management and output. The program  began the process of establishing a second system integration laboratory,   adding substantial testing and development capacity. The program also  began prioritizing and focusing its resources on incremental software  development as opposed to the much riskier concurrent development  approach. In addition, the program began implementing improvement  initiatives recommended by an independent software review, and  evaluated the possible deferral of some of the aircraft’s capabilities to  later blocks or moving them outside of the current F-35 program  altogether. At the same time, program data regarding software output  showed improvement. For example, program officials reported that the  time it took to fix software defects decreased from180 days to 55 days,  and the time it took to build and release software for testing decreased  from 187 hours to 30 hours.
section_title: Manufacturing Process Metrics Improved
paragraphs: Key manufacturing metrics and discussions with defense and contracting  officials indicate that F-35 manufacturing and supply processes improved  during 2012. While initial F-35 production overran target costs and  delivered aircraft late, the latest data through the end of 2012 shows labor  hours decreasing and deliveries accelerating. The aircraft contractor’s  work force has gained important experience and processes have matured  as more aircraft are built. We found that the labor hours needed to  complete aircraft at the prime contractor’s plant decreased, labor  efficiency since the first production aircraft improved, time to manufacture  aircraft in the final assembly area declined, factory throughput increased,  and the amount of traveled work declined. In addition, program data  showed that the reliability and predictability of the manufacturing  processes increased while at the same time aircraft delivery rates  improved considerably. Figure 1 illustrates the improvement in production  aircraft delivery time frames by comparing actual delivery dates against  the dates specified in the contracts.
section_title: F-35 Program Still Faces Risks
paragraphs: Ensuring that the F-35 is affordable and can be bought in the quantities  and time frames required by the warfighter will be of paramount concern  to the Congress, U.S. military and international partners. As we recently  reported, the acquisition funding requirements for the United States alone  are currently expected to average $12.6 billion per year through 2037,  and the projected costs of operating and sustaining the F-35 fleet, once  fielded, have been deemed unaffordable by DOD officials. In addition, the  program faces challenges with software development and continues to  incur substantial costs for rework to fix deficiencies discovered during  testing. As testing continues additional changes to design and  manufacturing processes will likely be required, while production rates  continue to increase.
subsections: section_title: Long-Term Affordability Remains a Concern
paragraphs: We recently concluded that while the March 2012 acquisition program  baseline places the F-35 program on firmer footing, the aircraft are  expected to cost more and deliveries to warfighters will take longer than  previously projected. The new baseline projects the need for a total of  $316 billion in development and procurement funding from 2013 through  2037, or an average of $12.6 billion annually over that period (see figure  2). Maintaining this level of sustained funding will be difficult in a period of  declining or flat defense budgets and competition with other “big ticket  items” such as the KC-46 tanker and a new bomber program. In addition,  the funding projections assume the financial benefits of the international  partners purchasing at least 697 aircraft. If fewer aircraft are procured in  total or in smaller annual quantities—by the international partners or the  United States—unit costs will likely rise according to analysis done by the  Office of the Secretary of Defense (OSD) Cost Assessment and Program  Evaluation (CAPE) office.
In addition to the costs for acquiring aircraft, we found that significant  concerns and questions persist regarding the cost to operate and sustain  the F-35 fleet over the coming decades. The current sustainment cost  projection by CAPE for all U.S. aircraft, based on an estimated 30-year  service life, exceeds $1 trillion. Using current program assumptions of  aircraft inventory and flight hours, CAPE recently estimated annual  operating and support costs of $18.2 billion for all F-35 variants compared  to $11.1 billion spent on legacy aircraft in 2010. DOD officials have  declared that operating and support costs of this magnitude are  unaffordable and the department is actively engaged in evaluating  opportunities to reduce those costs, such as basing and infrastructure  reductions, competitive sourcing, and reliability improvements.
Because of F-35 delays and uncertainties, the military services have   made investments to extend the service lives of legacy F-16 and F-18  aircraft at a cost of $5 billion (in 2013 dollars). The Navy is also buying  new F/A-18E/F Super Hornets at a cost of $3.1 billion (in then-year  dollars) to bridge the gap in F-35 deliveries and mitigate projected  shortfalls in fighter aircraft force requirements. As a result, the services  will incur additional future sustainment costs to support these new and  extended-life aircraft, and will have a difficult time establishing and  implementing retirement schedules for existing fleets.
section_title: Software Development Challenges Remain
paragraphs: Our report found that over time, F-35 software requirements have grown  in size and complexity and the contractor has taken more time and effort  than expected to write computer code, integrate it on aircraft and  subsystems, conduct lab and flight tests to verify it works, and to correct  defects found in testing. Although recent management actions to refocus  software development activities and implement improvement initiatives  appeared to be yielding benefits, software continued to be a very  challenging and high-risk undertaking, especially for mission systems.  While most of the aircraft’s software code has been developed, a  substantial amount of integration and test work remain before the  program can demonstrate full warfighting capability. About 12 percent of  mission systems capabilities have now been validated, up from 4 percent  about a year ago. However, progress on mission systems was limited in  2012 by contractor delays in software delivery, limited capability in the  software when delivered, and the need to fix problems and retest multiple  software versions. Further development and integration of the most  complex elements—sensor fusion and helmet mounted display—lie  ahead.
F-35 software capabilities are being developed, tested and delivered in  three major blocks and two increments—initial and final—within each  block. The testing and delivery status of the three blocks is described  below:
Block 1.0, providing initial training capability, was largely completed in  2012, although some final development and testing will continue.  Also, the capability delivered did not fully meet expected requirements  relating to the helmet, ALIS, and instrument landing capabilities.
Block 2.0, providing initial warfighting capabilities and limited  weapons, fell behind due to integration challenges and the  reallocation of resources to fix block 1.0 defects. The initial increment,  block 2A, delivered late and was incomplete. Full release of the final  increment, block 2B, has been delayed until November 2013 and will  not be complete until late 2015.
Block 3.0 providing full warfighting capability, to include sensor fusion  and additional weapons, is the capability required by the Navy and Air  Force for declaring their respective initial operational capability dates.  Thus far, the program has made little progress on block 3.0 software.  The program intends initial block 3.0 to enter flight test in 2013. This is  rated as one of the program’s highest risks because of its complexity.
section_title: Design Changes and Rework Continue to Add Cost and Risk
paragraphs: Although our recent review found that F-35 manufacturing, cost, and  schedule metrics have shown improvement, the aircraft contractor  continues to make major design and tooling changes and alter  manufacturing processes while development testing continues.  Engineering design changes from discoveries in manufacturing and  testing are declining in number, but are still substantial and higher than  expected from a program this far along in production. Further, the critical  work to test and verify aircraft design and operational performance is far  from complete. Cumulatively, since the start of developmental flight  testing, the program has accomplished 34 percent of its planned flights  and test points. For development testing as a whole, the program verified  11.3 percent of the development contract specifications through  November 2012. As indicated in table 1, DOD continues to incur financial  risk from its plan to procure 289 aircraft for $57.8 billion before completing  development flight testing.
This highly concurrent approach to procurement and testing increases the  risk that the government will incur substantial costs to retrofit (rework)  already produced aircraft to fix deficiencies discovered in testing. In fact,  the F-35 program office projects rework costs of about $900 million to fix  the aircraft procured on the first four annual procurement contracts.  Substantial rework costs are also forecasted to continue through the 10th  annual contract (fiscal year 2016 procurement), but at decreasing  amounts annually and on each aircraft. The program office projects about  $827 million more to rework aircraft procured under the next 6 annual  contracts.
section_title: DOD Actions On GAO Recommendations Have Varied, but F-35 Restructuring Was A Positive Step
paragraphs: We have reported on F-35 issues for over a decade and have found that  the magnitude and persistence of the program’s cost and schedule  problems can be largely traced to (1) decisions at key junctures made  without adequate product knowledge; and (2) a highly concurrent  acquisition strategy that significantly overlapped development, testing,  and manufacturing activities. Over that time, our reports included  numerous recommendations aimed at reducing risk in these areas and  improving the chances for successful outcomes.
DOD has implemented our recommendations to varying degrees. For  example, in 2001 we recommended that DOD delay the start of system  development until the F-35’s critical technologies were fully mature. DOD  disagreed with that recommendation and chose to begin the program with  limited knowledge about critical technologies. Several years later, we  recommended that DOD delay the production decision until flight testing  had shown that the F-35 would perform as expected, and although DOD  partially concurred with our recommendation, it chose to initiate  production before sufficient flight testing had been done. Citing concerns  about the overlap—or concurrency—among development, testing, and  production, we have recommended that DOD limit annual production  quantities until F-35 flying qualities could be demonstrated. Although  DOD disagreed with our recommendation at the time, it has since  restructured the F-35 program and, among other things, deferred the  production of hundreds of aircraft into the future, thus addressing the  intent of our recommendation and reducing program risk. Appendix ll lists  these and other key recommendations we have made over time, and  identifies the actions DOD has taken in response.
In conclusion, while the recent restructuring of the F-35 program placed it  on a firmer footing, tremendous challenges still remain. The program  must fully validate the F-35’s design and operational performance against  warfighter requirements, while at the same time make the system  affordable so that the United States and partners can acquire new  capabilities in the quantity needed and can then sustain the force over its  life cycle. Ensuring overall affordability will be a challenge as more  austere budgets are looming.
Chairman Durbin, Ranking Member Cochran and members of the  subcommittee, this completes my prepared statement. I would be pleased  to respond to any questions you may have.
section_title: GAO Contact and Acknowledgments
paragraphs: For further information on this statement, please contact Michael Sullivan  at (202) 512-4841 or sullivanm@gao.gov. Contact points for our Office of  Congressional Relations and Public Affairs may be found on the last page  of this statement. Individuals making key contributions to this statement  are Bruce Fairbairn, Travis Masters, Marvin Bonner, W. Kendal Roberts,  Megan Porter, Erin Stockdale, and Abby Volk.
section_title: Appendix I: Changes in Reported F-35 Program Quantity, Cost, and Deliveries, 2001- 2012
paragraphs: October 2001  (system  development start) baseline)
March 2007  (approved  baseline)
June 2010  (Nunn- McCurdy)
March 2012  (approved  baseline)
section_title: Appendix II: Prior GAO Reports and DOD Responses
paragraphs: Start of system development  and demonstration approved.
Primary GAO message  Critical technologies needed for  key aircraft performance  elements not mature. Program  should delay start of system  development until critical  technologies mature to  acceptable levels.
DOD response and actions  DOD did not delay start of  system development and  demonstration stating  technologies were at acceptable  maturity levels and will manage  risks in development.
The program undergoes re- plan to address higher than  expected design weight,  which added $7 billion and 18  months to development  schedule.
We recommended that the  program reduce risks and  establish executable business  case that is knowledge-based  with an evolutionary acquisition  strategy.
DOD partially concurred but did  not adjust strategy, believing  that its approach is balanced  between cost, schedule and  technical risk.
Program sets in motion plan  to enter production in 2007  shortly after first flight of the  non-production representative  aircraft.
The program planned to enter  production with less than 1  percent of testing complete. We  recommended program delay  investing in production until  flight testing shows that JSF  performs as expected.
DOD partially concurred but did  not delay start of production  because it believed the risk  level was appropriate.
Congress reduced funding for  first two low-rate production  buys thereby slowing the  ramp up of production.
Progress was being made but  concerns remained about  undue overlap in testing and  production. We recommended  limits to annual production  quantities to 24 a year until  flying quantities are  demonstrated.
DOD non-concurred and felt  that the program had an  acceptable level of concurrency  and an appropriate acquisition  strategy.
DOD implemented a Mid- Course Risk Reduction Plan  to replenish management  reserves from about $400  million to about $1 billion by  reducing test resources.
We believed new plan  increased risks and DOD  should revise it to address  testing, management reserves,  and manufacturing concerns.  We determined that the cost  estimate was not reliable and  that a new cost estimate and  schedule risk assessment is  needed.
DOD did not revise risk plan or  restore testing resources,  stating that it will monitor the  new plan and adjust it if  necessary. Consistent with a  report recommendation, a new  cost estimate was eventually  prepared, but DOD refused to  do a risk and uncertainty  analysis.
subsections: section_title: Est. dev. costs dev. length aircraft unit cost Key program event $44.4 Billion 13 years $104 Million
paragraphs: The program increased the  cost estimate and adds a year  to development but  accelerated the production  ramp up. Independent DOD  cost estimate (JET I) projects  even higher costs and further  delays.
Primary GAO message  Moving forward with an  accelerated procurement plan  and use of cost reimbursement  contracts is very risky. We  recommended the program  report on the risks and  mitigation strategy for this  approach.
DOD response and actions  DOD agreed to report its  contracting strategy and plans  to Congress and conduct a  schedule risk analysis. The  program completed the first  schedule risk assessment with  plans to update semi-annually.  The Department announced a  major restructuring reducing  procurement and moving to  fixed-price contracts.
The program was restructured  to reflect findings of recent  independent cost team (JET  II) and independent  manufacturing review team.  As a result, development  funds increased, test aircraft  were added, the schedule  was extended, and the early  production rate decreased.
Costs and schedule delays  inhibit the program’s ability to  meet needs on time. We  recommended the program  complete a full comprehensive  cost estimate and assess  warfighter and IOC  requirements. We suggest that  Congress require DOD to tie  annual procurement requests to  demonstrated progress.
DOD continued restructuring,  increasing test resources and  lowering the production rate.  Independent review teams  evaluated aircraft and engine  manufacturing processes. Cost  increases later resulted in a  Nunn-McCurdy breach. Military  services are currently reviewing  capability requirements as we  recommended.
Restructuring continued with  additional development cost  increases; schedule growth;  further reduction in near-term  procurement quantities; and  decreased the rate of  increase for future production.  The Secretary of Defense  placed the STOVL variant on  a 2 year probation; decoupled  STOVL from the other  variants; and reduced STOVL  production plans for fiscal  years 2011 to 2013.
The restructuring actions are  positive and if implemented  properly, should lead to more  achievable and predictable  outcomes. Concurrency of  development, test, and  production is substantial and  provides risk to the program.  We recommended the program  maintain funding levels as  budgeted; establish criteria for  STOVL probation; and conduct  an independent review of  software development,  integration, and test processes.
DOD concurred with all three of  the recommendations. DOD  lifted STOVL probation, citing  improved performance.  Subsequently, DOD further  reduced procurement  quantities, decreasing funding  requirements through 2016. The  initial independent software  assessment began in and  ongoing reviews are planned  through 2012.
section_title: Est. dev. costs dev. length aircraft unit cost Key program event $55.2 Billion 18 years
paragraphs: The program established a  new acquisition program  baseline and approved the  continuation of system  development, increasing costs  for development and  procurements and extending  the period of planned  procurements by 2 years.
Primary GAO message  Extensive restructuring places  the program on a more  achievable course. Most of the  program’s instability continues  to be concurrency of  development, test, and  production. We recommend the  Cost Assessment Program  Evaluation office conduct an  analysis on the impact of lower  annual funding levels; JSF  program office conducts an  assessment of the supply chain  and transportation network.
DOD response and actions  DOD partially concurred with  conducting an analysis on the  impact of lower annual funding  levels and concurred with  assessing the supply chain and  transportation network. .
section_title: Related GAO Products
paragraphs: F-35 Joint Strike Fighter: Current Outlook Is Improved, but Long-Term  Affordability Is a Major Concern. GAO-13-309. Washington, D.C.: March  11, 2013.
Defense Acquisitions: Assessments of Selected Weapon Programs.  GAO-13-294SP. Washington, D.C.: March 28, 2013.
Joint Strike Fighter: DOD Actions Needed to Further Enhance  Restructuring and Address Affordability Risks.  GAO-12-437.   Washington, D.C.: June 14, 2012.
Joint Strike Fighter: Restructuring Added Resources and Reduced Risk,  but Concurrency Is Still a Major Concern. GAO-12-525T. Washington,  D.C.: March 20, 2012.
Joint Strike Fighter: Implications of Program Restructuring and Other  Recent Developments on Key Aspects of DOD’s Prior Alternate Engine  Analyses. GAO-11-903R. Washington, D.C.: September 14, 2011.
Joint Strike Fighter: Restructuring Places Program on Firmer Footing, but  Progress Still Lags. GAO-11-325. Washington, D.C.: April 7, 2011.
Joint Strike Fighter: Additional Costs and Delays Risk Not Meeting  Warfighter Requirements on Time. GAO-10-382. Washington, D.C.:  March 19, 2010.
Joint Strike Fighter: Accelerating Procurement before Completing  Development Increases the Government’s Financial Risk. GAO-09-303.  Washington D.C.: March 12, 2009.
Joint Strike Fighter: Recent Decisions by DOD Add to Program Risks.  GAO-08-388. Washington, D.C.: March 11, 2008.
Joint Strike Fighter: Progress Made and Challenges Remain.   GAO-07-360. Washington, D.C.: March 15, 2007.
Joint Strike Fighter: DOD Plans to Enter Production before Testing  Demonstrates Acceptable Performance. GAO-06-356. Washington, D.C.:  March 15, 2006.
Tactical Aircraft: Opportunity to Reduce Risks in the Joint Strike Fighter  Program with Different Acquisition Strategy. GAO-05-271. Washington,  D.C.: March 15, 2005.
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