Key facts
- A military investigation determined engine failure caused a fatal Army helicopter crash in February.
- Two soldiers died in the crash of an AH-1S Cobra helicopter during emergency landing training.
- The crash was attributed to a misaligned internal cylinder in the engine, causing shaft whirling and component failure.
- The Army is considering accelerating the retirement of the AH-1S Cobra helicopter.
- Aviation safety management functions will be transferred to Army Headquarters by April next year.
A military investigation has concluded that a sudden engine failure was the primary cause of a fatal helicopter crash in February that resulted in the deaths of two soldiers. The AH-1S Cobra helicopter, belonging to an Army aviation unit, crashed on February 9 during an emergency landing familiarization training in Gapyeong County, located approximately 55 kilometers northeast of Seoul.
According to the official findings released by Army officials on Thursday, the crash was attributed to a physical defect within the engine. Specifically, a slight misalignment of an internal cylinder caused the engine's central drive shaft to wobble. This wobble led to violent vibrations, a phenomenon known as "shaft whirling," where the spinning shaft moves erratically. When the pilot attempted to increase power to climb, the spinning power shaft collided with a second spinning shaft, generating extreme heat that melted critical components and led to the engine's shutdown.
An Army official stated in a press briefing that the accident was caused by an engine flameout resulting from a fault in the exhaust diffuser's internal cylinder, ruling out environmental or human errors. The Army is now considering accelerating the retirement of the AH-1S model, which was first introduced in 1988 and deployed in 1991, with retirement initially planned to begin in 2028. The military also plans to coordinate with the Defense Acquisition Program Administration to adjust the deployment schedule for its replacement, the LAH-1 Miron, to ensure its smooth introduction.
To enhance oversight and safety, the Army announced it will transfer aviation safety management functions and personnel from the Army Aviation Command to the Army Headquarters Combat Readiness and Safety Group by April of the following year. For airfields that operate both helicopters and drones, the Army intends to improve the safety management system by implementing integrated inspections for manned and unmanned platforms, moving away from individual checks.