US Government Accountability Office (GAO) - F-35 Reports
¶ B1. US Government Accountability Office (GAO) -- F-35 Reports
¶ Update through 6 September 2026
GAO, 11 June 2026: US fleet mission-capable time (at least one mission) fell from 67% in fiscal 2021 to 44% in 2025; fully mission-capable time (all missions) fell from 38% to 25%. These are US fleet measures, not Swiss readiness figures. The GSS Reset needs an estimated additional USD 13.7 billion through fiscal 2031. Parts capacity and contract incentives remain risks. GAO-26-108113 · GAO PDF
Modernisation, GAO follow-up in July 2026: The Block 4 cost-transparency recommendation remains open. Technology-readiness and engine-upgrade reviews are planned for December 2026, not completed. This updates recommendations from a 2023 report. GAO-23-106047
¶ Historical archive
The GAO has issued over 50 recommendations on the F-35 programme since 2001. The Department of Defense has implemented only about half of them.
| Date | Report | Title | Key Finding |
|---|---|---|---|
| 2023 | GAO-23-106047 | F-35 JSF: More Actions Needed to Explain Cost Growth | Cost growth insufficiently explained, transparency lacking |
| 2023 | GAO-23-105341 | F-35: DOD Needs to Reassess Sustainment Strategy | Sustainment strategy requires fundamental overhaul |
| Apr 2024 | GAO-24-106703 | F-35 Sustainment: Costs Continue to Rise | Sustainment costs: USD 1.58 trillion lifecycle; availability declining |
| May 2024 | GAO-24-106909 | F-35 JSF: Production Issues and Modernization Delays | Block 4 costs: from 10.6 to 16.5 billion USD (+56%); TR-3 problems |
| Sep 2025 | GAO-25-107632 | F-35 JSF: Actions Needed to Address Late Deliveries | Deliveries 238 days late (2024); Block 4 earliest in 2031 |
| 2025 | GAO-25-108104 | Military Readiness: Persistent Challenges | F-35 sustainment as a challenge with 700+ jets in service |
| 2025 | GAO Blog | F-35 Will Now Exceed $2 Trillion | Total programme costs exceed 2 trillion USD |