Accident Sequence
During the climb after takeoff, the aircraft's engine began surging and producing loud noises. The power output steadily decreased while the noise from the engine compartment increased. Unable to maintain the assigned attitude, the pilot descended in instrument meteorological conditions until breaking out of clouds approximately 800 to 1,000 feet above ground level.
Recognizing that he could not reach the airport, the pilot attempted a power-out forced landing on a nearby road. As the aircraft descended to about 20 feet above the road surface, a car pulled onto the roadway. During the landing sequence, the aircraft impacted the rear of the car.
Engine Examination
Subsequent investigation determined that the loss of engine power resulted from the fracture of the number seven crankshaft cheek. This fracture occurred due to the propagation of a fatigue crack initiation point. Materials laboratory examination of the crankshaft did not reveal any clear reason for the creation of that initiation point.
Other Circumstances
The pilot flew in instrument conditions before the forced landing. The aircraft's exact type, registration, and operator were not specified in the report. No information was provided regarding injuries or damage beyond the collision with the car.