Misplaced flashlight leads to $4 million in damages to F-35 engine

 21. 01. 2024      Category: Air force

In a startling incident at Luke Air Force Base in Arizona, early 2023 witnessed an unusual yet costly mishap involving one of the most advanced fighter jets in the world - the F-35. A seemingly minor oversight, the misplacement of a handheld flashlight, led to nearly $4 million in damages to the aircraft's engine, as revealed by a recent Air Force accident investigation report.

Picture: Pratt Whitney F135 afterburning turbofan engine used on F35 Lightning | Shutterstock

The incident

On the night of March 15, during a maintenance procedure on an F-35 belonging to the 56th Fighter Wing, a routine check quickly turned problematic. The maintenance team, comprising three maintainers, initiated an engine ground run without any initial complications. This procedure included a five-minute idling process to monitor fuel leaks.

However, it was during the engine shutdown that one maintainer detected abnormal noises, a sign of the impending discovery of damage. Fortunately, no injuries were reported among the airmen involved.

The cause

The root cause of this incident, as identified in the investigation, was traced back to a handheld flashlight. This flashlight had been inadvertently sucked into the engine’s air intake during the ground run. The sequence of events leading to this mishap began when one of the maintainers completed a tool inventory check after installing a metering plug into an engine fuel line. Subsequently, another maintainer used the flashlight for a “Before Operations Servicing” inspection but failed to retrieve it.

Contributing factors

The investigation highlighted multiple factors contributing to this oversight. Primarily, it was a deviation from the standard cautionary measures outlined in the Joint Technical Data checklist. This negligence was a significant factor in leaving the flashlight behind.

Furthermore, the report noted a degree of "complacency" related to the F-35's Autonomic Logistics Information System (ALIS). Investigators pointed out the overwhelming number of checklists and the difficulty in accessing the correct ones, leading to a lax attitude towards adhering to required maintenance procedures.

Extent of damage

The forgotten flashlight wreaked havoc on the aircraft's engine. The mishap damaged various critical components, including the second, third, fifth, and sixth stage rotors, fuel nozzle, bypass duct, high-pressure compressor, high-pressure turbine, and fan inlet variable vane. The total estimated cost of the damages amounted to a staggering $3,933,106.


The incident concluded with a clear indication of human error. The inspecting maintainer failed to clear the inlet of foreign objects after completing the required inspections. This failure to adhere to checklist tasks resulted in the expensive oversight of leaving a flashlight inside the engine inlet, emphasizing the importance of rigorous adherence to maintenance protocols in aviation, particularly with advanced and sensitive aircraft like the F-35.

 Author: Michal Fencl