NTSB Identification: WPR12LA341
14 CFR Part 91: General Aviation
Accident occurred Tuesday, July 31, 2012 in Cody, WY
Probable Cause Approval Date: 04/10/2014
Aircraft: FAIRCHILD HILLER FH-1100, registration: N5038F
Injuries: 4 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The pilot reported that while in cruise flight, the rear of the helicopter suddenly began to vibrate. He performed an autorotation to a field, and the helicopter landed hard. The tailboom and main transmission mounts were substantially damaged. The pilot reported that a tail rotor driveshaft coupling had split in half, which resulted in a loss of tail rotor drive. Postaccident examination of the tail rotor driveshaft coupling revealed that the coupling failure was initiated by fatigue cracking. A complete history of the part was not available; therefore, the total time in service of the part could not be determined.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The failure of a tail rotor driveshaft coupling due to fatigue.

Full narrative available

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