Accident Overview
During an instructional flight, the aircraft experienced a partial loss of engine power while on a visual approach to the runway. The flight instructor reported that the engine was operating normally before the rpm abruptly decreased from 2,200 to approximately 1,300. The carburetor heat was in the OFF position during the approach. Efforts to regain engine power were unsuccessful, and the instructor executed a forced landing to a field.
Landing and Damage
The airplane touched down short of the airport, nosed over, and came to rest inverted. Postaccident examination revealed that the vertical stabilizer and rudder were bent. No mechanical anomalies that would have precluded normal operation were identified.
Engine Examination
The engine was test run at various power settings with no anomalies noted. Although a carburetor icing probability chart indicated that the ambient temperature and dew point at the time of the accident favored serious carburetor icing at glide power, the pilot reported that the engine was not at glide power when the power loss occurred.
Investigation Outcome
Based on the available evidence, the investigation was not able to identify the reason for the power loss.