Sikorsky S-55B N5663 accident near Chelan, Washington

Probable cause

The pilot’s failure to maintain clearance from power lines while maneuvering at a low altitude.

NTSB analysis

The helicopter was contracted to overfly the rural cherry orchard in order to dry the cherries following rain showers. A witness reported that the helicopter was flying over the cherry orchard from south to north, and it had just completed a left turn when it collided with power lines that bordered the orchard. The helicopter impacted terrain, in a nose low attitude, about 45 feet south of the power lines. Power line wires were found wrapped 3 to 4 times around the main rotor mast and striation marks on the leading edge of the main rotor blades were indicative of a wire strike.

Examination of the accident site revealed that four wires were strung between poles with the top three wires about 50 feet agl and the lower wire about 40 feet agl. Postaccident examination of the airframe and engine revealed no evidence of a preimpact mechanical malfunction or failure that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR11FA350 for the full record.