Incident Overview
During a low-level coyote predation flight at approximately 40 feet altitude and 40 knots airspeed, the pilot of a McDonnell Douglas 369E helicopter (equipped with a Rolls-Royce (Allison) 250-C20B turboshaft engine) heard a loud bang. Simultaneously, both the "Engine Out" and "Auto Relight" warning lights illuminated. The pilot immediately reduced collective pitch and initiated a forced landing. The helicopter touched down hard on uneven terrain, resulting in the separation of the right skid.
Post-Crash Examination
Post-crash examination of the engine revealed that the compressor coupling adapter had fractured circumferentially. This fracture caused a complete disconnection of the compressor from the turbine assembly. The Rolls-Royce (Allison) manufactured compressor adapter coupling had been installed approximately 1,005 hours prior to the incident. The separation was determined to be the result of multiple fatigue fractures in the coupling, which were associated with severe fretting on the adapter's outer diameter where it inserts into the spur adapter gearshaft.
Aircraft and Engine Details
The helicopter was a McDonnell Douglas 369E model, originally designed by Hughes. The engine was a Rolls-Royce (Allison) 250-C20B turboshaft engine. No further details on registration, operator, or location were provided in the source.