Fast Facts

DOD is getting closer to completing the F-35 program, but DOD's plan to move into full-rate production without fixing key deficiencies brings into question the reliability and affordability of the aircraft.

DOD has already requested $9.8 billion for 2019 and will ask for about $10.4 billion more per year over the next two decades.

Congress should consider withholding funding from the next increment of F-35 development until DOD provides an independent cost estimate, a technology assessment, and takes other actions. In addition, we recommended that DOD resolve critical aircraft deficiencies before moving to full-rate production.

An F-35B, the short takeoff and vertical landing variant for the Marine Corps, is shown landing on USS America.

Photo of an F-35 surrounded by white smoke landing.

Photo of an F-35 surrounded by white smoke landing.

Skip to Highlights

What GAO Found

The Department of Defense (DOD) has made progress in completing the F-35 baseline development program, but plans to finish testing later than expected.

F-35 Testing Schedule Is Delayed

F-35 Testing Schedule Is Delayed

DOD plans to defer resolving some critical deficiencies found in testing until after its full-rate production decision in October 2019, even though DOD's policy states that critical deficiencies generally will be resolved before then. Program officials stated it is reasonable to resolve some deficiencies while in production. Any associated rework could result in additional costs to the government.

DOD plans to spend billions of dollars to modernize the F-35 with new capabilities and is requesting $278 million to begin that process before establishing a sound business case—a baseline cost and schedule estimate.

Funding Request for F-35 Modernization, Known as Block 4, Is Premature

F-35 Testing Schedule Is Delayed

This timing could prompt Congress to make a funding decision before DOD can provide its business case. With these funds, DOD can award a contract, making a long-term commitment to Block 4, the costs of which are not fully understood.

Why GAO Did This Study

In 2019, DOD will decide whether to enter full-rate production for the F-35 aircraft, the most expensive and ambitious weapon acquisition program in U.S. military history. DOD has already requested the $9.8 billion it will need for 2019, and it will continue to request more over the next two decades—about $10.4 billion annually. However, the F-35 is just one program in DOD's vast acquisition portfolio, raising questions about its long-term affordability.

The National Defense Authorization Act for Fiscal Year 2015 included a provision for GAO to review the F-35 acquisition program until it reaches full-rate production. This is GAO's third report under this provision. It assesses progress of development and testing, including remaining deficiencies, and plans for spending on new capabilities.

To conduct this work, GAO reviewed and analyzed management reports and historical test data; discussed key aspects of F-35 development with program management and contractor officials; and compared acquisition plans to DOD policies and GAO acquisition best practices.

Reissued with Revisions Jun. 13, 2018

This report was revised June 13, 2018 to correct four figures in table 1 on page 4.
Skip to Recommendations


Congress should consider providing in future appropriations that no funds shall be available for obligation for F-35 Block 4 until DOD provides a sound business case for the effort. GAO is making two recommendations to DOD, including that it resolve all critical deficiencies before full-rate production. DOD concurred with both recommendations and cited that it would resolve all critical deficiencies before its full-rate production decision.

Matter for Congressional Consideration

Matter Status Comments
Congress should consider providing in future appropriations that no funds shall be available for obligation for F-35 Block 4 until DOD provides a report setting forth its complete acquisition program baseline for the Block 4 effort to the congressional defense committees. Such a report must reflect findings from (1) an independent cost estimate, (2) technology readiness assessments, (3) a test and evaluation master plan, (4) a system engineering plan, (5) a preliminary design review, and (6) an approved acquisition strategy.
Closed - Implemented
In August 2018, Congress passed the National Defense Authorization Act (NDAA) for Fiscal Year 2019 (Public Law No: 115-232), which limited the program from obligating or expending more than 75 percent of funds authorized for the F-35 Continuous Capability Development and Delivery effort. This limitation would be in effect until 15 days after the Secretary of Defense submitted a detailed cost and schedule baseline for the program. The program submitted its F-35 Block 4 report to Congress in May 2019 which contained cost and schedule information, responding to this provision.

Recommendations for Executive Action

Agency Affected Recommendation Status
Department of Defense 1. The Secretary of Defense should direct the F-35 program office to resolve all critical deficiencies before making a full-rate production decision. (Recommendation 1)
DOD concurred with our recommendation and stated that critical deficiencies would be resolved before full-rate production, due in December 2019. In May 2020, we reported that DOD delayed its full-rate production decision from December 2019 to between September 2020 and March 2021.
Department of Defense
Priority Rec.
This is a priority recommendation.
2. The Secretary of Defense should direct the F-35 program office to identify what steps are needed to ensure the F-35 meets reliability and maintainability requirements before each variant reaches maturity and update the Reliability and Maintainability Improvement Program with these steps. (Recommendation 2)
DOD concurred with our recommendation. According to a DOD official, as of March 2021, the F-35 program office is in the process of revising its plan for improving the F-35's reliability and maintainability (R&M) performance, but has not revised R&M requirements, which the program office considers to be unachievable. Specifically, the program (1) updated the F-35 Life-Cycle Sustainment Plan (LCSP) to identify the program's R&M performance goals; (2) revised the Reliability and Maintainability Improvement Plan (RMIP) to more clearly, identify how R&M improvements projects will drive increased F-35 reliability, availability and maintainability; and (3) established the 5th Generation Maintenance Performance to Plan to outline the specific steps the program is taking to achieve the LSCP goals through those projects identified in the RMIP. The official noted that the R&M requirements, as defined in the Operational Requirements Document at the start of the development effort, are not achievable and that the DOD is evaluating what actions it will take to revise those R&M requirements. Until it does so, we consider this recommendation to remain open.

Full Report

GAO Contacts