Accident Details
A helicopter equipped with a reciprocating engine experienced a loss of engine power while in cruise flight. The pilot, a student with 115 hours of flight experience, reported sensing a change in torque or an unusual indication. In response, the pilot activated the carburetor heat, but engine power continued to decay gradually.
Emergency Maneuver
The pilot performed an autorotation to a marsh area. During the forced landing, the main rotor blade contacted the tailboom assembly, resulting in the separation of the tailboom from the rest of the airframe.
Post-Accident Examination
A post-accident examination of both the airframe and the engine revealed no evidence of any pre-impact anomalies. The carburetor heat control was found in the automatic mode, the engine sparkplugs appeared normal, and the fuel cell contained approximately a half-tank of fuel. Investigators were unable to determine the reason for the reported loss of engine power.