Accident Sequence
A flight instructor and a student pilot were conducting a training flight in a helicopter. With both pilots on the controls, at an altitude of about 10 feet above the ground, the instructor initiated a simulated engine failure autorotation with a power recovery. As they rolled the engine throttle up to recover, the alternator light illuminated and "the engine quit."
At approximately two feet above the ground, the flight instructor raised the collective fully and leveled the helicopter. The low rotor rpm light then illuminated and the low rotor rpm horn sounded. The helicopter landed hard, bounced, and settled back onto the runway. During the landing sequence, the main rotor blade struck the tailboom. The pilot reported that the alternator light turned off during the accident sequence.
Damage
The helicopter sustained substantial damage to the tailboom.
Post-Accident Findings
A Federal Aviation Administration inspector interviewed the flight instructor, who stated that the engine might have had a low idle setting and that during the accident flight, he had applied full carburetor heat. The inspector noted that because the accident occurred more than three years before it was reported by an anonymous person, he was unable to determine the reason for the reported power loss.
The instructor further reported that during a post-accident engine run, the engine started and ran without any issues.