Primary finding
Probable cause
The pilot's failure to see and avoid a powerline while flying at low altitude over a river.
Investigator assessment
Analysis narrative
The pilot reported that, while flying low along the river, the helicopter collided with an unseen wire. The pilot subsequently accomplished a landing in the shallow water of the river without further incident. A main rotor blade was substantially damaged. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.