Primary finding
Probable cause
The pilot's inadequate preflight inspection in which he failed to remove the tail rotor covers, which resulted in the failure of the tail rotor drive shaft during engine start.
Investigator assessment
Analysis narrative
According to the pilot, while conducting a preflight inspection, he overlooked the removal of the tail rotor covers. He started the helicopter and shortly thereafter he heard a "snap", and the helicopter began to "shake". The helicopter was immediately shutdown and a visual inspection revealed substantial damage to the tail rotor drive shaft. The pilot reported no other preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.
Source record
Factual narrative
According to the pilot, while conducting a preflight inspection, he overlooked the removal of the tail rotor covers. He started the helicopter and shortly thereafter he heard a "snap", and the helicopter began to "shake". The helicopter was immediately shutdown and a visual inspection revealed substantial damage to the tail rotor drive shaft. The pilot reported no other preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.