F-35 stealth fighter jets are only capable of flying missions a little over half the time, watchdog finds

"Maintenance challenges negatively affect F-35 aircraft readiness," the Government Accountability Office wrote in a new report.

• A new government watchdog report reveals that the F-35 program is plagued by maintenance issues.
• Because of these problems, the stealth fighters can only fly a mission just over half the time.
• "Maintenance challenges negatively affect F-35 aircraft readiness," the report noted. 

The US military's F-35 fighters are only capable of flying missions just over half the time due to serious maintenance issues, according to a watchdog review of the Pentagon's long-term procurement plans for the stealth aircraft.  

The new findings, included in a lengthy report published on Thursday by the Government Accountability Office (GAO), come just days after a F-35B Lightning II Joint Strike Fighter crashed over South Carolina during a training mishap, leading the US Marines Corps to issue a two-day pause to all flights over ongoing safety concerns. 

The F-35, a highly advanced fifth-generation aircraft, represents a "growing portion" of the Pentagon's tactical aviation fleet, the GAO report said, but it determined in the report, which was delivered to lawmakers, that the expensive F-35 program is plagued by maintenance issues and the jet's future sustainment strategy must be evaluated.

"Maintenance challenges negatively affect F-35 aircraft readiness," the GAO report said. "The F-35 fleet mission capable rate — the percentage of time the aircraft can perform one of its tasked missions — was about 55 percent in March 2023, far below program goals." Mission capable rates are for aircraft possessed by a squadron.

"The program was behind schedule in establishing depot maintenance activities to conduct repairs," the GAO found, and "as a result, component repair times remained slow with over 10,000 waiting to be repaired — above desired levels. At the same time, organizational-level maintenance has been affected by a number of issues, including a lack of technical data and training."

There are several specific issues that the GAO cited in its report, among them being that the US government relies heavily on contractors — thus limiting its decision-making abilities — and there being inadequate maintenance-related training. Additionally, there is a lack of spare parts, support equipment, and technical data, all of which can cause maintenance delays at military installations.

There have also been delays in setting up service facilities, where complex repairs are handled, the GAO said. 

In a bid to remedy the situation, the GAO said it has made several recommendations to the Pentagon, "including reassessing F-35 sustainment elements to determine government and contractor responsibility and any required technical data, and making final decisions on changes to F-35 sustainment to address performance and affordability." It noted that the Pentagon has agreed with the GAO's recommendations.

The US military currently fields around 450 F-35s, and the Pentagon plans to procure around 2,500 more as part of a decades-long program with an estimated life cycle cost of over $1.7 trillion. The GAO said most of this funding will go to operating, maintaining, and repairing the fighter jets.

There are three variants of the Lockheed Martin F-35. The F-35A is used by the Air Force and brings in capabilities beyond what aging F-16s and A-10s can provide while the F-35C represents an improvement over other Navy carrier-based fighters like the F/A-18. And the F-35B is a short-takeoff/vertical landing variant able to be used by the Marine Corps aboard amphibious assault ships and smaller airfields.

The B variant, which costs around $100 million, made headlines earlier this week when a Marine Corps pilot was forced to eject from the fighter due to a malfunction that occurred during a Sunday training mission over South Carolina.

While the unidentified pilot managed to safely eject, parachuting into a residential backyard, it was not immediately clear what happened to the jet — prompting the military to ask for the public's help in finding it. Officials said the next day that they had located a field of debris belonging to the aircraft. 

Shortly after the incident was made public, the Marine Corps announced a two-day pause to all flights, citing what it said was a string of "aviation mishaps" in recent weeks, which, in addition to the the F-35 crash, included two separate crashes involving a F/A-18 fighter jet and a MV-22B Osprey — leaving four Marines dead and over 20 more injured.