Incident Overview
During a dual instructional lesson, a certified flight instructor (CFI) initiated a practice autorotation from 1,000 feet above ground level (agl) while operating in the traffic pattern. According to the CFI, as the helicopter descended through 800 feet agl, all engine power was suddenly lost, converting the planned maneuver into a forced landing. Prior to the power loss, all engine and flight instruments had been indicating within normal ranges ("in the green").
Sequence of Events
The CFI reported that the helicopter touched down softly at the approach end of the runway, with a forward ground speed estimated between 2 and 3 miles per hour. After touchdown, the helicopter pitched forward, shook violently, and the main rotor blade struck the airframe. This impact caused substantial damage to the helicopter.
Damage
The accident resulted in substantial damage to the helicopter due to the main rotor blade contacting the airframe. No other damage details were provided.
Investigation
No probable cause was determined from the information provided.