Cessna 172K N46492 accident near Belfast, Maine

Probable cause

The flight instructor’s failure to ensure the radio was set correctly to activate the pilot-controlled lighting, which resulted in poor positioning for a proper landing and a subsequent off-runway forced landing during an attempted go-around. Contributing to the accident was a partial loss of engine power due to carburetor ice.

NTSB analysis

According to the pilots, while in cruise flight at 6,500 feet mean sea level, the engine lost partial power. The flight instructor applied full rich mixture and carburetor heat. Maintaining partial engine power, the flight diverted to a nearby airport. The pilots were unable to activate the pilot-controlled lighting at the airport and elected to utilize the airport's rotating beacon to locate the runway. The runway was located; however, the airplane was not in a position to make a landing, and the flight instructor applied full power in order to perform a go-around. During the go-around the engine experienced a total loss of power, and the flight instructor subsequently executed a forced landing to a nearby road. During the landing, the airplane struck a utility pole and nosed over. A postaccident test run of the engine revealed no evidence of any mechanical anomalies. According to postaccident photographs of the cockpit, the audio control panel was selected to Comm 1; however, Comm 2 was the radio that was set to the airport's common traffic advisory frequency, which was used for the pilot-controlled lighting. The airplane was operating in conditions conducive to serious carburetor icing at cruise power at the time of the accident. The probability existed that the airplane was operated in an area conducive to induction icing, and, although the flight instructor applied carburetor heat, the accumulation of the ice was greater than the application of heat could melt. It is further possible that during the go-around the abrupt throttle movement to the full power setting caused the total loss of engine power.

Text from the NTSB. Open the NTSB docket for ERA12LA241 for the full record.