Bell 206B N770HP accident near Whiteside, Tennessee

Probable cause

The pilot’s failure to maintain clearance from the powerlines.

NTSB analysis

The pilot and the passenger/observer, who were both law enforcement personnel, were flying in a helicopter on a law enforcement mission when it struck a marked, 1-inch diameter, energized (161K volt) aluminum high-tension powerline cable. The high-tension powerlines were about 430 ft tall and about 3,800 ft long. A witness was driving on a nearby interstate when he observed the helicopter flying low and close to the powerlines. The witness reported that he was concerned the helicopter was going to hit the lines. He described the helicopter as hovering, and it did not appear to be in distress. The witness then saw the helicopter strike the powerlines and observed an “arc.” The helicopter spun a few times as it descended and went out of view.

The helicopter came to rest in heavily wooded and steep mountainous terrain, which resulted in substantial damage to the fuselage, main rotor, and tail rotor. A postaccident examination of the airframe and engine revealed no evidence of any preimpact mechanical malfunctions and failures that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for ERA22FA383 for the full record.