A flashlight left inside an F-35’s engine during maintenance work destroyed the $14 million engine at Luke Air Force Base in Arizona, according to Air Force officials. 

The mistake by a team of three maintainers damaged the F-35’s engine “beyond local repair,” according to a Ground Accident Investigation Board report released Thursday.

The mistake was made, the report found, by a maintenance team that did not properly account for every piece of their tool kit after performing maintenance on the jet, a bedrock principle of aircraft repair. The report also found that the team did not follow an established Air Force directive to check an engine before it is run and to not wear loose items on their person while working on an engine.

No one was injured in the mishap. The flashlight caused $3,933,106 in damage, the report said. 

The maintenance was done by the 56th Aircraft Maintenance Squadron within the 56th Fighter Wing at Luke Air Force Base. 

Luke is a primary training base for pilots and crews in the Air Force and the 56th wing trains and qualifies personnel on the F-35. According to an Air Force release, since 1941, Luke has graduated over 61,000 pilots and turns out 105 F-35 pilots, every year.

The mishap came just one month before Luke graduated its 2,000th F-35 pilot in April.

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On March 15, 2023, a maintenance team installed a metering plug into an engine fuel line, a relatively routine task, on one of the base’s otherwise healthy F-35As. The addition of the plug was mandated across the Air Force’s F-35 fleet to fix an issue discovered after a mishap with the fuel system in December 2022. The F-35 was “one of the last aircraft that needed to be completed,” according to the report.

After the plug was installed, the final step of the repair was to check for leaks with the engine running. Though the report concluded that the flashlight was ingested during the engine test, the plane’s sensors did not indicate pickup any “foreign object ingestion.”

But as the crew finished the job, their ears told them something was off.

“During the shutdown, the [mishap team] reported hearing abnormal noises as the engine was spinning down,” the report said.

After shutdown, a maintainer found damage to the engine’s blades.

Luke officials would not say if any of the maintainers involved had faced punishment for the mishap.

“Any administrative actions taken regarding the F-35 incident on 15 March are not releasable,” Capt. Scarlett Trujillo, spokesperson for the Air Education and Training Command, told Task & Purpose.

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