F-35 Sustainment: DOD Needs to Cut Billions in Estimated Costs to Achieve Affordability
Fast Facts
DOD plans to acquire nearly 2,500 F-35 aircraft for about $400 billion. It projects spending another $1.27 trillion to operate and sustain them—an estimate that has steadily increased since 2012.
The military services collectively face tens of billions of dollars in sustainment costs that they project will be unaffordable. For example, the Air Force needs to reduce estimated annual per-plane costs by $3.7 million (47%) by 2036, or costs in that year alone will be $4.4 billion more than it can afford.
We recommended, among other things, that Congress consider making future F-35 acquisitions contingent on progress reducing sustainment costs.
An F-35B Performing a Vertical Landing at Naval Air Station Patuxent in Maryland
Highlights
What GAO Found
F-35 mission capable rates—a measure of the readiness of an aircraft fleet—have recently improved, but still fall short of warfighter requirements. Specifically, from fiscal year 2019 to fiscal year 2020, the U.S. F-35 fleet's average annual (1) mission capable rate—the percentage of time during which the aircraft can fly and perform one of its tasked missions—improved from 59 to 69 percent; and (2) full mission capable rate—the percentage of time during which the aircraft can perform all of its tasked missions—improved from 32 to 39 percent. Both metrics fall below the services' objectives. For example, in fiscal year 2020 the Air Force F-35A full mission capable rate was 54 percent, versus a 72 percent objective.
Since 2012, F-35 estimated sustainment costs over its 66-year life cycle have increased steadily, from $1.11 trillion to $1.27 trillion, despite efforts to reduce costs. The services face a substantial and growing gap between estimated sustainment costs and affordability constraints—i.e., costs per tail (aircraft) per year that the services project they can afford—totaling about $6 billion in 2036 alone (see fig.). The services will collectively be confronted with tens of billions of dollars in sustainment costs that they project as unaffordable during the program.
Gap between F-35 Affordability Constraints and Estimated Sustainment Costs in 2036
Note: Costs are in constant year 2012 dollars, as that was the year when the F-35 program was most recently re-baselined.
aSteady state years for the F-35 program are defined in each respective service's affordability analysis as: US Air Force/F-35A – 2036-2041; US Marine Corps/F-35B – 2033-2037; US Navy/F-35C – 2036-2043. Steady state refers to the program's peak operating point.
The Air Force needs to reduce estimated costs per tail per year by $3.7 million (or 47 percent) by 2036 or it will incur $4.4 billion in costs beyond what it currently projects it could afford in that year alone. Cost reductions become increasingly difficult as the program grows and matures. However, GAO found that there is no agreed upon approach to achieve the constraints. The F-35 program estimates that it will declare Milestone C—a decision point for moving into full-rate production of the aircraft—sometime in the 2021-2023 time frame. Without assessing cost-reduction efforts and program requirements (such as number of planned aircraft), and developing a plan prior to declaring Milestone C, the Department of Defense (DOD) may continue to invest resources in a program it ultimately cannot afford. Congress's requiring DOD to report on its progress in achieving affordability constraints and making F-35 procurements contingent on DOD's demonstrated progress would enhance DOD's accountability for taking the necessary and appropriate actions to afford sustaining the F-35 fleet.
Why GAO Did This Study
The F-35 aircraft, with its advanced capabilities, represents a growing portion of DOD's tactical aviation fleet—with about 400 of the aircraft fielded. DOD plans to procure nearly 2,500 F-35s at an estimated life cycle costs of the program exceeding $1.7 trillion—with $1.3 trillion of those costs being associated with operating and sustaining the aircraft.
A House Report accompanying the National Defense Authorization Act for Fiscal Year 2020 included a provision for GAO to review F-35 sustainment efforts. This report, among other things, assesses the extent to which (1) the F-35 has met warfighter-required mission capable rates; and (2) DOD has reduced the F-35's estimated life cycle sustainment costs and made progress in meeting its affordability constraints. GAO reviewed program documentation, analyzed performance and cost data, collected data from F-35 locations, and interviewed officials.
Recommendations
Congress should consider (1) requiring DOD to report annually on progress in achieving the affordability constraints, and (2) making F-35 aircraft procurement decisions contingent on DOD's progress in achieving these constraints. GAO is making four recommendations to DOD, including assessing cost reduction efforts and F-35 program requirements, and developing a plan to afford to sustain the future F-35 fleet. DOD partially concurred stating it will work to meet the intent of the recommendations in an expeditious manner. GAO continues to believe DOD should address the recommendations prior to declaring Milestone C.
Matter for Congressional Consideration
| Matter | Status | Comments |
|---|---|---|
| Congress should consider requiring the Under Secretary of Defense for Acquisition and Sustainment, in consultation with the services and the F-35 Joint Program Office, to report annually on progress in achieving the services' affordability constraints, including the actions taken and planned to reduce sustainment costs. (Matter for Consideration 1) | As of February 2025, Congress has not required the Department of Defense to report annually on the progress in achieving the service's affordability constraints. | |
| Congress should consider making future F-35 aircraft procurement decisions contingent on DOD's progress in achieving F-35 sustainment affordability constraints. (Matter for Consideration 2) | In Section 141 of the National Defense Authorization Act for Fiscal Year 2022, Congress took steps to limit the quantity of F-35s procured by the military services beginning in fiscal year 2029 based on their ability to achieve affordability cost targets. These steps meet the intent of our matter for consideration; therefore, we are closing this action. |
Recommendations for Executive Action
| Agency Affected | Recommendation | Status |
|---|---|---|
| Department of Defense | The Secretary of Defense should ensure that, prior to the Milestone C decision, the Under Secretary of Defense for Acquisition and Sustainment, in consultation with the services and the F-35 Joint Program Office, assess and document DOD's ability to meet the services' affordability constraints with existing or planned cost-reduction efforts. (Recommendation 1) |
DOD agreed with the substance of the recommendation. Prior to declaring Milestone C in March 2024, the military services provided their affordability assessments in support of Milestone C to the F-35 Joint Program Office, according to documentation we reviewed. Subsequently, in December 2024, the F-35 Joint Program Office used these assessments to produce an Affordability Position for Milestone C document that provided updates in development, production, and sustainment for the program. Specifically, the document highlighted the military services' affordability constraints and discussed other potential cost savings measures that were being tracked by the F-35 Joint Program Office's War on Cost. The focus was to ensure cost reduction initiatives are being executed to achieve the military services' affordability constraints. According to DOD officials, the information provided in this document, including the Department's ability to meet the military services' affordability constraints, was reviewed by the Under Secretary of Defense prior to making a Milestone C/Full Rate Production decision. Considering these collective efforts taken by the Department, the intent of our recommendation was met.
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| Department of Defense | The Secretary of Defense should ensure that, prior to the Milestone C decision, the Under Secretary of Defense for Acquisition and Sustainment, in consultation with the services and the F-35 Joint Program Office, assess and document changes in service-related program requirements (e.g., the number of aircraft purchases and flying hours) to achieve cost-reductions. (Recommendation 2) |
DOD agreed with the substance of the recommendation. In February 2024, DOD officials told us that as part of their respective fiscal year 2023 budget submissions, the Department of the Air Force and Department of the Navy conducted detailed reviews of their planned future F-35 aircraft purchases and flying hours. These reviews were also reflected in the military services' updated F-35 beddown plans and subsequent budget submissions. In April 2024, we reported that, as a result of these reviews, the military services had made progress meeting their affordability targets. In the annual F-35 program cost estimate in 2023, the military services reassessed programs requirements, including the beddown of the aircraft and the number of hours each aircraft is estimated to fly. This analysis and additional analysis conducted prior to Milestone C contributed to the conclusion that the services' affordability targets could be met or were very close to being met. The F-35 program's assessment and documentation of program requirements in conjunction with its planned activities to meet affordability constraints in preparation for Milestone C met the intent of our recommendation.
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| Department of Defense | The Secretary of Defense should ensure that, prior to the Milestone C decision, the Under Secretary of Defense for Acquisition and Sustainment, in consultation with the services and the F-35 Joint Program Office, develop and document a program-wide plan for achieving affordability constraints with detailed actions tied to milestones and resources. (Recommendation 3) |
DOD agreed with the substance of the recommendation. According to DOD officials, the F-35 Joint Program Office's War on Cost is being used as the mechanism to ensure that cost reduction initiatives are being executed to achieve the military services' affordability constraints. Furthermore, F-35 Joint Program Office's War on Cost effort was restructured prior to Milestone C to represent program-wide activities and governance mechanisms. According to War on Cost documentation dated prior to the program declaring Milestone C, the War on Cost effort intends to develop and document cost savings initiatives to, among other things, improve cost estimates and reduce overall costs. As part of this effort, designated team leads are responsible for tracking an affordability plan that includes reporting on the plans to achieve targets, any changes in those plans, risks, and necessary resources. According to DOD officials, new cost savings initiatives will continue to be identified within the War on Cost effort and tracked as part of the overall affordability plan. Considering the efforts taken by the F-35 Joint Program Office's War on Cost in support of Milestone C, the intent of our recommendation has been met.
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| Department of Defense | The Secretary of Defense should ensure that, prior to the Milestone C decision, the Under Secretary of Defense for Acquisition and Sustainment, in consultation with the services and the F-35 Joint Program Office, develop and document a risk-management approach for addressing potential challenges or making adjustments in order to achieve affordability objectives. (Recommendation 4) |
DOD agreed with the substance of the recommendation. According to DOD officials, the F-35 Joint Program Office's War on Cost includes a risk-based approach to achieving affordability. The F-35 Joint Program Office's War on Cost initiative is set up so those responsible for carrying out the program's affordability plan must highlight risks to meeting that plan, as well as identify the resources need to overcome those risks. For example, according to documentation dated prior to the program declaring Milestone C, each cost savings opportunity under considerations required estimated cost savings, progress status (identifying potential risk), the stage of maturity, and required resources. According to DOD officials, resources are prioritized to address cost savings opportunities based on the probability of success. In addition, Congress has imposed requirements on DOD and the F-35 Joint Program Office to reach its affordability targets by fiscal year 2029. If the F-35 Program Office does not meet its affordability targets, then the number of purchased requirement will be reduced, according to the statute. As a result, DOD and the F-35 Joint Program Office are monitoring its progress achieving the affordability constraints closely according to officials. Considering these efforts taken by the F-35 Joint Program Office, the intent of our recommendation was met.
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