Primary finding
Probable cause
The certified flight instructor did not select an adequate landing site for the practice autorotation.
Investigator assessment
Analysis narrative
The certified flight instructor (CFI) was demonstrating a touchdown autorotation from an altitude of 1,500 feet above ground level to a turf runway. He stated that, during the maneuver, the helicopter's sink rate seemed high, so he continued to pull pitch to arrest the descent rate. The helicopter touched down with a slight forward speed on a downhill slope, and the rear portion of the skids became momentarily stuck in the soft turf. The helicopter pitched forward after breaking loose from the turf, and the main rotor blade contacted the vertical stabilizers and tail rotor drive shaft cover, resulting in substantial damage. The CFI stated that there were no mechanical malfunctions or anomalies with the helicopter.
Source record
Factual narrative
The certificated flight instructor (CFI) was demonstrating a touchdown autorotation from an altitude of 1,500 feet above ground level to a turf runway. He stated that during the maneuver, the helicopter's sink rate seemed high, so he continued to pull pitch to arrest the descent rate. The helicopter touched down on soft turf with a slight forward speed on a downhill slope. The rear portion of the skids became momentarily stuck in the soft turf. The helicopter pitched forward after breaking loose from the turf, and the main rotor blade contacted the vertical stabilizers and tail rotor drive shaft cover, resulting in substantial damage. The pilot stated there were no mechanical malfunctions or anomalies with the helicopter.