Bell UH1 N75140 accident near Enterprise, Alabama

Probable cause

The in-flight separation of a turn lock fastener stud, which resulted in substantial damage to one tail rotor blade.

NTSB analysis

The operator reported that following an uneventful flight, the pilot-in-command conducted a postflight inspection of the helicopter and noted a missing turn lock fastener stud on the tail rotor driveshaft cover of the vertical stabilizer. Additionally, the leading edge of one tail rotor blade near the blade tip was substantially damaged. The missing fastener was not located. The pilot reported that the fastener had been in place prior to the accident flight and that the tail rotor blade was not damaged. Thus, the fastener likely separated in-flight and contacted the tail rotor blade. The helicopter’s most recent inspection was completed about 2 months and 77 flight hours before the accident flight.

Text from the NTSB. Open the NTSB docket for ERA26LA193 for the full record.