Primary finding
Probable cause
The loss of power to the right engine due to a fractured crankshaft while the left engine was secured. Factors were the dual students failure to use carburetor heat while performing maneuvers and the unsuitable terrain.
Investigator assessment
Analysis narrative
The dual student had performed several maneuvers with the left engine windmilling and did not use carburetor heat when carburetor icing conditions prevailed. Upon completing a maneuver and returning to cruise flight, a power loss occurred to the left engine. The instructor took over the flight controls and initiated a normal descent toward a nearby airport. During the descent, he secured the left engine. As the airplane turned base to final approach, the right engine's crankshaft fractured and a forced landing had to be made to unsuitable terrain approximately 1/4 mile from the runway. The left engine was successfully test run after the accident. A teardown of the right engine revealed the fractured crankshaft.
Source record
Factual narrative
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