Summary
On 15 March 2023 at 2138 local time, an F-35A Lightning II aircraft, tail number 14-5103, assigned to the 56th Fighter Wing at Luke Air Force Base, Arizona, sustained foreign object damage (FOD) during a maintenance ground run. The mishap occurred while the aircraft was undergoing a Time Compliance Technical Directive (TCTD) to install a metering plug in an engine fuel line. No personnel were injured during the incident. The foreign object, a handheld flashlight, caused damage to the engine valued at $14 million, which was deemed beyond local repair capabilities.
Sequence of Events
The mishap team (MT) arrived for the maintenance swing shift at 1430 local time. All team members were current and qualified for their assigned tasks. Weather conditions, including high winds, rain, and thunderstorms within five nautical miles of the airfield, caused maintenance operations to be suspended for approximately one hour. After the weather delay, the MT was tasked with completing a TCTD on the mishap aircraft. To perform the TCTD, the team removed a panel and inserted a metering plug into an engine fuel line. The aircraft was then prepared for an engine run to test for fuel leaks. The engine run was completed without any visual indications or health reporting codes suggesting an abnormal condition. After engine shutdown, the MT reported hearing a noise from the decelerating engine. A post-engine run inspection by mishap member 1 revealed significant damage to the engine.
Maintenance Findings
The investigation found that an incomplete tool kit inventory and failure to comply with Joint-Service Technical Data guidance prior to engine start resulted in the foreign object damage. The Board President identified contributing factors, including F-35 Autonomic Logistics Information System (ALIS) checklist complacency and a disconnect between Department of the Air Force Instruction 21-101 tool inventory guidance and unofficial local procedures.
Board Opinion
The Board President determined by a preponderance of evidence that a handheld flashlight caused the damage to the aircraft. The mishap was attributed to procedural lapses: an incomplete tool inventory and noncompliance with technical data guidance. The board noted that the checklist complacency and local procedural deviations were contributing factors.