Accident Overview
A commercial pilot and a pilot-rated passenger were conducting a training exercise involving a pinnacle approach, culminating in a hover over a gravel pile situated within a rock quarry. According to the commercial pilot, during the transition to a hover, the helicopter continued to descend and the left skid made contact with the top of the gravel pile. In response, the pilot applied full collective pitch and left cyclic control inputs, but these actions did not produce a noticeable change in the helicopter's attitude.
Sequence of Events
Following the impact, the helicopter began to roll to the right and subsequently descended down the embankment of the gravel pile. After the accident, the pilot reported that a dynamic roll over had occurred. The helicopter was examined, along with its associated system components. No evidence of a mechanical malfunction or failure was found during this examination.
Investigation Findings
The investigation did not identify any pre-existing mechanical issues that could have contributed to the accident. The pilot's account of the dynamic roll over was consistent with the observed damage and flight path. No additional causal factors were determined.