What happened
On 15 March 2023, during a maintenance ground run at Luke Air Force Base, Arizona, an F-35A, tail number 14-5103, experienced significant engine damage. The maintenance task was being performed by the 62d Aircraft Maintenance Unit to complete a Time Compliance Technical Directive (TCTD), which involved installing a metering plug into an engine fuel line and testing for leaks.
Following the installation, the team conducted an engine run. While the engine showed no initial signs of abnormal operation or health reporting codes during the run, the crew noted an unusual noise as the engine was decelerating. A subsequent inspection revealed that a handheld flashlight had been ingested into the engine, resulting in no injuries but causing damage estimated at approximately $3.9 million.
The investigation
The Accident Investigation Board examined the sequence of events leading to the foreign object damage (FOD). The investigation reviewed the maintenance procedures, the technical data used by the crew, and the environmental conditions present during the shift. Weather delays caused by high winds, rain, and nearby lightning had previously interrupted operations earlier that day.
The board also scrutinized the tool inventory processes and the digital systems used to manage maintenance tasks on the flightline. The investigation focused on why a handheld flashlight remained in the engine inlet area prior to the engine start.