Descent and Power Loss
During a descent from 21,000 feet to 2,500 feet, the pilot reduced power to idle. He believed he had set the mixture to rich for the descent, as recommended by the aircraft handbook. When he added power to intercept the glideslope, the propeller sounded as if it ran away. The pilot concluded an engine failure had occurred.
Restart Attempt and Forced Landing
The pilot turned the electric boost pump to the high position and attempted to restart the engine. The engine fired several times but did not start. A forced landing was made in a tree farm, during which the aircraft nosed over.
Post-Accident Examination
After the accident, fuel stains were found on the top of each wing near the fuel caps. Large areas of dirt under the wings smelled of fuel. After recovery, a fuel supply was connected and the engine was started; it operated with no evidence of failure or malfunction. The propeller and propeller governor were inspected with no abnormalities found.
Handbook Guidance
The aircraft handbook stated that the mixture should be placed to rich for all idle power descents. It also stated that while restarting the engine in flight, the electric boost pump should be operated on high for 2-3 seconds, then switched to low. If left on high, the engine would flood, which would be indicated by the engine firing several times but not starting.