Accident Overview
A helicopter sustained a hard landing after the engine lost power about one minute into flight. The pilot had refueled before departure. Approximately one minute after takeoff, while at about 500 feet above ground level (AGL), the engine lost power. The pilot entered an autorotation and established a glide toward a field ahead.
Autorotation and Landing
As the helicopter approached the field, the pilot raised the collective to clear a house and a ditch. Subsequently, main rotor rpm decreased, and the helicopter touched down hard.
Postcrash Examination
Examination of the helicopter revealed that the engine PC (power control) air line had separated near the attaching nut on the compressor scroll end. Metallurgical analysis showed that the tube had separated due to fatigue cracking, which was induced by installation damage. No other preaccident failure or malfunction of the engine, helicopter structure, or flight controls was found.
Engine Performance
Representatives from Allison Engine Company stated that the engine would go to minimum fuel flow after separation of the PC line.