Incident Overview
A certificated flight instructor was conducting a normal practice autorotation in a helicopter. During the maneuver, he observed the rotor RPM in the green, an indicated airspeed of 55 knots, and the aircraft in trim. At an altitude estimated to be between 50 and 100 feet above ground level, just prior to where he would have initiated a deceleration, the airspeed had bled off to approximately 20 knots, and the aircraft developed a high rate of descent.
Power Recovery Attempt
The instructor attempted a power recovery to arrest the descent, but the aircraft continued to descend and landed hard. The impact caused the tail rotor to separate from the airframe. The helicopter then bounced back into the air, landed hard a second time, and subsequently rolled over.
Relevant Handbook Information
According to the pilot's operating handbook (POH), the combination of altitude and airspeed at which the instructor attempted the recovery fell within a designated flight avoidance area. This condition prevented the pilot from performing remedial action effectively.
Investigation Findings
No probable cause was explicitly stated in the available information. The incident highlights the importance of understanding flight avoidance areas as defined in the aircraft's operating handbook.