Incident
A helicopter conducting a wildlife survey at approximately 50 feet above ground level (AGL) in mountainous terrain experienced a power loss while cruising at a slow airspeed of 35-40 knots. The aircraft's automatic systems momentarily restored power, but a complete loss of power then occurred. The pilot executed an emergency autorotation, which resulted in the helicopter contacting trees on sloping terrain.
Investigation
Post-accident examination of the helicopter revealed that the fuel system was intact, the automatic ignition system functioned properly, and the engine air intake was clear of obstructions. Subsequent functional testing of the engine demonstrated that it performed to manufacturer specifications. No component failures or malfunctions were identified that could account for the power loss.
Conclusion
The investigation did not determine a definitive cause for the power loss. The engine and related systems were found to be operational and within normal parameters.