Hughes 269C N9490F accident near Asotin, Washington

Probable cause

The pilot's failure to maintain adequate clearance from power lines while maneuvering in a canyon.

NTSB analysis

**This report was modified on September 30, 2016. Please refer to the public docket for this accident to view the original report.**

The private pilot and passenger were on a local area flight. While maneuvering in a canyon, the helicopter impacted power lines and descended to the canyon's wall. A fire ensued and burned the surrounding area. The power lines were located 350 ft south of the wreckage with two 35-ft support structures (wood poles) on either side of the canyon about 1,452 ft apart. The two 5/16-inch diameter power lines were oriented east-west and ran horizontally parallel to one another.

Ground scar analysis and wreckage fragmentation revealed that the helicopter contacted the power lines in the area of the swashplate. According to the helicopter manufacturer, if the helicopter were in level flight at cruise speed, 0.11 seconds would transpire between the contact with the first wire (canopy) and the second wire (slat and mast). Given the damage and rub marks, it is likely that, after the second wire impact, the helicopter pitched up and yawed left. Examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.

The private pilot had about 55 hours total time, most of which was accumulated around the accident area.

Text from the NTSB. Open the NTSB docket for WPR15FA204 for the full record.