Robinson Helicopter R44 N97UP accident near Westby, Wisconsin

Probable cause

The pilot's failure to see and avoid power lines while maneuvering at low altitude.

NTSB analysis

The helicopter pilot reported that, during an agricultural application flight, he performed a "high…[reconnaissance]" pass over the field and observed houses, tree lines, and power lines surrounding the field. He added that he descended for the first pass, about 70 mph and 100 to 150 ft above ground level, and as he approached the end of the field, he "suddenly became aware of two [additional] large power lines stretched out in front of [him] at eye level and closing fast." He further added that he "instinctively pulled up on the collective and back on the cyclic," and the fuselage cleared the wire, but suddenly there was a "violent lurch" when the tail rotor contacted the wire. Subsequently, the helicopter started to "spin out of control," the pilot braced for impact, and the helicopter impacted the terrain.

The fuselage, tailboom, and main rotor sustained substantial damage.

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

Text from the NTSB. Open the NTSB docket for GAA17CA491 for the full record.