Primary finding
Probable cause
The pilot’s improper landing flare during a practice autorotation.
Investigator assessment
Analysis narrative
The pilot said that while practicing an autorotation, the helicopter did not slide forward on the landing as he had expected, and instead came to a quick stop. The pilot rated passenger said the helicopter did not slide forward like a typical run-on landing, but “bucked” forward as it came to a quick stop just after it touched down. The pilot subsequently felt a vibration in the anti-torque pedals and shut the helicopter down. Postaccident examination of the helicopter revealed that the tail rotor drive shaft was bent and the cowling around the area of the bend had ruptured. Given that the helicopter was operating normally prior to the landing, it is likely that the forces imparted by (or were the result of) the pilot’s control inputs during the landing resulted in the damage to the tail rotor drive shaft.