GAO says deficient maintenance leaves US F-35s well below mission-capable rate goal

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.