Accident Sequence
The helicopter was operating in mountainous terrain at an elevation of 10,000 feet. The pilot landed the helicopter in an open area at the bottom of a canyon, where passengers boarded. After boarding, the helicopter was in a hover. The pilot observed that the torque gauge indicated 85–89 percent, the turbine outlet gas temperature was within the green range, and all other parameters were normal.
The pilot then turned the helicopter to the left to align with the takeoff area. During the turn, the torque gauge reading increased to 92 percent and stabilized. Subsequently, the torque gauge dropped to about 50 percent, and the helicopter began a rapid, uncontrolled left turn and descended. When the pilot applied collective pitch, the low rotor RPM audio warning activated, and the helicopter started a rapid, uncontrolled right turn.
The helicopter then impacted on a hill, rolled to the left, and came to rest in snow. The reason for the reported loss of engine power was not determined.
Post-Impact
The helicopter came to rest in snow after impacting a hill and rolling left. No further details about the aircraft condition or occupants were provided.