Approach and Loss of Control
According to the investigation, the helicopter was approaching a mountainous landing zone situated at an elevation of approximately 8,600 feet. As the pilot applied full collective control input, the helicopter entered an uncontrolled spin and descending trajectory, subsequently impacting the terrain.
Pilot Actions and Witness Account
The pilot later reported that he was unable to arrest a rightward turning motion despite applying full left antitorque pedal. He communicated to a ground witness that the helicopter had “lost tail rotor” effectiveness. The investigation found no evidence of preimpact failure of the airframe, drive train, or flight controls.
Investigation Findings
Examination of the wreckage revealed no preimpact anomalies in the airframe, drive train, or flight control systems. The helicopter’s loss of directional control occurred during a critical phase of approach in high-altitude mountainous conditions.