What happened
During an instructional flight, a helicopter was performing a practice autorotation when the engine ceased operation. The pilot reported that immediately after reducing the throttle and lowering the collective, the engine stopped. This loss of power was confirmed by split needles, zero engine RPM, and manifold pressure rising to atmospheric pressure.
The situation transitioned from a planned practice maneuver into an unplanned autorotation to touchdown. Upon impacting the terrain, the main rotor blade flexed downward and struck the tail boom section, which caused the tail rotor to separate. The aircraft sustained substantial damage during the event.
At the time of the accident, the weather consisted of winds from 220 degrees at 13 knots, gusting to 19 knots.
The investigation
An examination of the wreckage revealed no anomalies prior to the impact. Additionally, a subsequent test run demonstrated that the engine was operational.