What happened
The pilot reported that while the aircraft was operating in cruise flight, a loud pop was heard emanating from the rear section of the helicopter. Immediately following this noise, the turbine engine began to spool down rapidly. In response to the loss of power, the pilot initiated an emergency autorotation with the intention of running onto the landing area.
During the descent and flare phase of the maneuver, the tail rotor struck the ground. This impact caused the aircraft to roll over. The post-accident physical examination of the wreckage confirmed that the failure originated from a broken number two turbine shaft bearing.
The investigation
Examination of the helicopter after the accident revealed mechanical evidence pointing to the source of the in-flight failure. Investigators identified that the number two turbine shaft bearing had failed, which led to the subsequent loss of turbine function and the forced landing sequence.