Incident Summary
While en route, the pilot reported hearing a clanking noise behind him, immediately followed by a severe vibration of the flight controls. In response, he initiated an autorotative descent from an altitude of 3,000 feet. The helicopter subsequently began to roll to the left before righting itself. The aircraft touched down with a forward speed of approximately 50 miles per hour, then rolled over and was destroyed.
Investigation Findings
An investigation into the accident revealed that the control rotor cuff, part number 36124-3, had failed. The failure was attributed to fatigue. No further details regarding the aircraft type, registration, operator, location, or occupants were specified in the source.
Probable Cause
The probable cause of the accident was the fatigue failure of the control rotor cuff (PN 36124-3), which led to a loss of control during the subsequent autorotation and landing.