Primary finding
Probable cause
The pilot’s failure to maintain clearance from static power lines.
Investigator assessment
Analysis narrative
The pilot said that he positioned the helicopter behind a moving truck as it was traveling down the highway to film the contents in the truck's bed. Unaware that terrain was rising, he observed a static power line across the helicopter's path at the last second. He attempted to avoid the power line by flying underneath it; however, the main rotor mast impacted a wire. He performed a successful autorotation to the ground. The helicopter's tail boom, tail rotor, vertical stabilizer, and main rotor control linkages sustained substantial damage. The pilot reported no preimpact mechanical malfunctions or failures with the helicopter that would have precluded normal operation.
Source record
Factual narrative
While flying a film director and camera man, the pilot positioned the helicopter behind a moving truck to film the contents in the truck's bed. Unaware that terrain was rising, the pilot observed a static power line across the helicopter's path at the last second. The pilot attempted to avoid the power line by flying underneath it; however, the main rotor mast impacted a wire. The pilot was able to perform a successful autorotation to the ground. The helicopter's tail boom, tail rotor, vertical stabilizer, and main rotor control linkages sustained substantial damage. The pilot reported no preimpact mechanical malfunctions or failures with the helicopter that would have precluded normal operation.