Accident Details
On July 31, 2012, about 0920 mountain daylight time, a Fairchild Hiller FH-1100 helicopter, registration N5038F, was substantially damaged following the failure of its tail rotor drive shaft and subsequent autorotation to a hard landing near Cody, Wyoming. The commercial pilot and his three passengers were not injured. The helicopter was being operated by the pilot, doing business as Eclipse Helicopter Services, Cody, under the provisions of 14 Code of Federal Regulations Part 91. No flight plan had been filed for the local personal flight, which had originated about 1 hour before the accident. Visual meteorological conditions prevailed.
Pilot Report
According to the pilot, while in cruise flight, a sudden onset of vibration was felt coming from the rear of the helicopter. He immediately performed an autorotation to a field straight ahead. During the landing sequence, the helicopter spun 180 degrees to the right. The landing skids, tail boom, and main transmission mounts were bent. The pilot reported that a tail rotor driveshaft coupling, identified as a Bendix 19E101-1D coupling, had split in half, resulting in a loss of tail rotor drive.
Postaccident Examination
Postaccident examination of the tail rotor driveshaft coupling by the National Transportation Safety Board's Materials Laboratory in Washington, D.C., revealed that the coupling failed due to fatigue cracking. A complete history of the part was not available; therefore, the total time in service of the part could not be determined.