Hiller UH-12E N703WA accident near Fobes Hill, Washington

Probable cause

The pilot’s abrupt maneuver to avoid a powerline during an aerial application flight, which resulted in the helicopter’s impact with terrain.

NTSB analysis

The pilot reported that he was conducting an aerial application flight in a field that was crossed by three sets of powerlines. The pilot had previously flown the helicopter under the powerlines, but as the helicopter once again approached them, the pilot perceived they were too low to fly under. The pilot began a hard turn to the right to avoid the wires, and the helicopter “lost lift due to excessive turn and bank.” As a result, the spray boom and main rotor contacted the ground, and the helicopter subsequently rolled over, resulting in substantial damage to the fuselage and tail boom.

The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR25LA246 for the full record.