What happened
The pilot was conducting a downwind takeoff with two passengers on board. At the time of departure, reported wind conditions included gusts reaching 25 knots. The aircraft was loaded approximately 130 pounds below its maximum gross weight limit.
Shortly after becoming airborne, the pilot reported a sudden loss of power. In response to this emergency, the pilot initiated an autorotation procedure. However, during the descent, directional control could not be maintained. Consequently, the helicopter's tail rotor struck a moving vehicle on the ground, followed by a collision with the terrain.
The investigation
Examination and testing of the engine revealed normal operation with no mechanical malfunctions detected. Further inspection identified that a fuel nozzle in the aircraft's system was installed without its required restrictor. To compensate for this missing component, the fuel servo idle mixture had been adjusted to a very lean setting.
Findings
Despite the non-standard fuel system configuration, the improper installation of the fuel nozzle and the resulting lean mixture setting were determined not to be a factor in the accident. The loss of power occurred despite the aircraft being under gross weight limits.