What happened
A commercial pilot with 1,672 flight hours was conducting a routine patrol of the Rio Grande River near the international border. After reaching the edge of the designated search area, the pilot turned back toward the operations base but diverted to investigate two law enforcement airboats located north of the port of entry.
During the outbound leg of the patrol, the pilot had observed two sets of power lines. While attempting to orbit the airboats after crossing the first set of wires, the pilot encountered the second set of power lines. Upon realizing a collision was imminent, the pilot attempted an instinctive cyclic climb to clear the obstacle. This maneuver was initiated too late, and the tail rotor struck the wires.
The impact caused the separation of the vertical fin, the tail rotor assembly, and the tail rotor gearbox. Despite the damage, the pilot maintained controlled flight and decided to perform an autorotation into a clearing. The helicopter completed a successful autorotation and landed upright in the river, approximately 853 feet from the site of the wire strike.
Findings
The aircraft came to rest in approximately 3 feet of water. The pilot performed an emergency engine shutdown and exited the aircraft through the pilot door with help from the crews of the nearby airboats. There were no injuries reported following the incident.