Accident Sequence
The 1,672-hour commercial pilot departed the operations base near the border for a routine patrol of the Rio Grande River dividing the two countries. Upon reaching the limits of his search area, he reversed course to return to home base. On the return leg, he decided to search an area where he had noticed two law enforcement airboats operating north of the port of entry. According to the pilot's statement on the NTSB Form 6120.1/2, he recalled seeing two sets of power lines on the outbound leg of his patrol. After crossing the first set of power lines and locating the airboats, he began a turn to orbit the boats. The pilot added that when he looked up and saw that he was about to hit the second set of wires, he instinctively initiated a cyclic climb to clear the wires. However, the maneuver was initiated too late, and the tail rotor impacted the wires, resulting in the separation of the tail rotor gear box, tail rotor assembly, and vertical fin.
Post-Impact Actions
The pilot managed to keep the helicopter in controlled flight and elected to execute an autorotation to a clearing. The helicopter made a successful autorotation and landed upright in the middle of the river, 853 feet from the point of the wire strike. The helicopter came to rest in about 3 feet of water, and the pilot performed an emergency engine shutdown and egressed through the pilot door with assistance from the crews of the airboats.