Accident Sequence
A helicopter operating as a public-use instructional flight sustained substantial damage following a practice autorotation that turned into a real loss of engine power. The pilot reported that after turning off the throttle and lowering the collective, the engine stopped. This was indicated by split needles and an engine RPM gauge reading zero, along with a manifold pressure gauge rising to atmospheric pressure. The practice maneuver became an actual autorotation to touchdown.
On touchdown, the main rotor blade flexed downward and contacted the tail boom, leading to the separation of the tail rotor. The wind at the time was from 220 degrees at 13 knots, gusting to 19 knots.
Examination Findings
An examination of the wreckage revealed no preimpact anomalies. The engine was subsequently test run and found to be operational. No malfunctions or failures were identified in the examination.