Incident Overview
An experimental certificated helicopter sustained damage during a test flight conducted as part of the height-velocity diagram development for the 206L4 certification program. The test pilot was performing aborted takeoffs when, at an altitude of 30 feet and an airspeed of 50 knots, he initiated an autorotation.
Sequence of Events
During the autorotation, the collective pitch control was lowered slightly, leading to a high rate of descent. As the helicopter descended, main rotor RPM decreased. The pilot applied collective pitch before touchdown, but this action did not arrest the descent rate. The helicopter subsequently landed hard, resulting in buckling of the tailboom and separation of the tail rotor drive shaft.
Damage and Findings
The hard landing caused structural damage to the tailboom and the tail rotor drive shaft. The investigation did not specify any injuries to the pilot or other individuals. The event occurred during a routine test flight aimed at expanding the flight envelope for the helicopter model.