Primary finding
Probable cause
The pilot's failure to maintain clearance from a tree while conducting an external load operation.
Investigator assessment
Analysis narrative
The commercial pilot reported that, while hovering the helicopter and maneuvering aft about 60 ft above ground level during an external load operation, the tail rotor impacted a tree. He immediately lost yaw control, and the helicopter began to rapidly turn right. The main rotor then impacted trees, and the helicopter spun to the ground. The helicopter was destroyed by a postcrash fire. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.