Primary finding
Probable cause
A reported stuck throttle for reasons that could not be determined during postaccident examinations and subsequent loss of control during hover.
Investigator assessment
Analysis narrative
According to the pilot, he was performing the first flight after a condition inspection. He put the helicopter into a hover, noted the “throttle locked up and [the helicopter] got away” from him. The helicopter rolled onto its side and impacted the ground, which resulted in substantial damage to the fuselage and tailboom. Furthermore, he reported an overspeed and “hard vibration” prior to the rollover. A post-accident examination of the helicopter revealed no evidence of any pre-accident mechanical malfunctions or failures that would have precluded normal operation. In addition, the throttle governor was bench tested with no anomalies noted.