Accident Overview
A helicopter pilot encountered a complete engine failure while patrolling utility lines at an altitude of 700 feet above ground level (AGL). The pilot initiated an autorotative glide toward an open field. During the descent, the pilot maneuvered to avoid trees close to the ground, at which point the main rotor RPM decayed. The helicopter could not be leveled before the tail rotor struck the ground.
Post-Accident Examination
A detailed examination of the helicopter and its components did not reveal any mechanical problems. The engine and attached systems were inspected, and no material or system malfunctions were detected. The helicopter was found to be capable of normal autorotation performance.
Pilot Actions
The investigation determined that the pilot allowed the rotor RPM to decay below the point at which recovery could be achieved without the helicopter sustaining damage. This was the second accident involving the same pilot as pilot-in-command where autorotative procedures were called into question.