Incident Summary
A helicopter accident occurred while a certified flight instructor (CFI) and a student were performing simulated power-off autorotations with power recovery. During the maneuver, the main rotor rpm began to decay.
Sequence of Events
At an altitude of approximately 150 to 200 feet above ground level (agl), the CFI took control of the helicopter. About 50 feet agl, the CFI executed a flare. Realizing that the helicopter was going to settle, the CFI attempted a run-on landing. However, the helicopter landed hard, causing the skid landing gear to spread.
After the hard landing, the helicopter slid approximately 75 feet down the runway. It then departed the runway surface and rolled four times before coming to rest on its left side. The CFI stated that there were no mechanical problems with the helicopter.
Investigation
The accident investigation focused on the training maneuver and pilot actions. The helicopter's main rotor rpm decay during the autorotation was a key aspect. The CFI's flare and subsequent run-on landing attempt did not prevent the hard landing. The helicopter's skid landing gear spread upon impact, and the subsequent slide and roll resulted in the aircraft coming to rest on its left side.
No other details about the aircraft, occupants, or environmental conditions were provided in the source. The CFI's statement that no mechanical issues were present suggests that the accident was not due to a mechanical failure.