Incident Overview
A pilot was conducting low-level wildlife surveillance in a helicopter. The atmosphere was reported as humid. During refueling, the pilot noticed condensation accumulating on the carburetor due to the humid air.
Flight and Power Loss
After departing, approximately five minutes into the flight, the pilot observed that the carburetor air temperature gauge was reading in the lower one-third of the yellow caution range. In response, he adjusted the carburetor heat control lever. Subsequently, the engine lost power.
Forced Landing and Damage
The pilot performed an autorotation to an open area. The helicopter landed hard. During the landing, the main rotor blade contacted and severed the tail boom. Additionally, the extended landing gear legs collapsed.
Probable Cause
No probable cause was stated in the source.
Conclusion
The incident highlights a sequence of events involving carburetor ice-related indications and a subsequent power loss following the adjustment of carburetor heat. The hard landing resulted in significant structural damage to the helicopter.