GAO says deficient maintenance leaves US F-35s well below mission-capa…

Grounded: the US Marine Corps' Lockheed Martin F-35Bs have lower mission-capable rates than their US Air Force counterparts; all types are well below their goals. (Lockheed Martin)

The Lockheed Martin F-35 is available to perform its scheduled missions 55% of the time, according to a US Government Accountability Office (GAO) report released on 21 September. The agency found fault in the Department of Defense's (DoD's) line and depot maintenance practices.

The report measured F-35 mission-capable (MC) rates through March 2023. The GAO attributed low MC rates largely to maintenance issues. Citing a DoD analysis, the GAO wrote that having the full array of maintenance capabilities would allow for a 65% MC rate for the US Marine Corps' F-35B and US Navy's F-35C and a 75% MC rate for the US Air Force's F-35A.

The top 10 culprits behind non-MC rates – including the engine, distributed aperture system sensor, integrated core processor power supply, and power thermal management system controller – cannot yet be repaired by DoD maintenance centres and must be sent back to manufacturers.

Full depot maintenance capabilities are not anticipated to be ready until 2027, the GAO wrote, finding that the DoD has the capability to perform only 44 of the 68 tasks required of depot maintenance centres. In addition, the GAO found a 141-day backlog for repairs, 81 days beyond the DoD's 60-day goal. DoD officials who spoke with the GAO largely attributed the delays to a lack of materials, although access to those materials was expected to improve through the end of 2023. “These officials also told us that they were still years away from achieving the program's [time] goal,” said the GAO.