Primary finding
Probable cause
The pilot’s failure to maintain clearance from power lines during power line maintenance.
Investigator assessment
Analysis narrative
The pilot reported that while hovering near power lines, for the purpose of installing bird diverters, a gust of wind pushed the helicopter “into the OPGW wire.” The pilot repositioned the helicopter away from the wire and then saw it fly up and into the rotor system. He immediately started a controlled landing and safely landed the helicopter. The helicopter sustained substantial damage to all five rotor blades. The pilot reported that there were no mechanical anomalies with the helicopter before the wire strike that would have precluded normal operation. The pilot reported that the helicopter operator is adding local weather stations to augment reported weather when the flight crews are working in remote areas. Additionally, for skid operations, the operator has restricted the steady state wind and gust spreads by zone for the helicopter.