What happened
During a night flight intended for training a student pilot on dark night takeoff procedures, the helicopter's engine lost power shortly after climbing through 100 feet. In response to the loss of power, the flight instructor initiated an autorotation procedure.
As the aircraft reached the touchdown phase of the autorotation, it collided with the ground. The impact caused the helicopter to undergo landing gyrations, during which a main rotor blade severed the tail boom and the aircraft rolled over.
The investigation
A post-impact examination of the helicopter revealed no mechanical problems with the aircraft. To further investigate the power loss, the engine assembly was removed from the airframe and placed into an engine test cell. During a functional test run, the engine operated smoothly across all power ranges.