What happened
After leveling off at 2,300 feet near the destination airport, the pilot reported that the engine quit. The pilot attempted to restart the engine, but these efforts were unsuccessful. During an emergency descent intended for a forced landing over a wooded area, the airplane collided with trees and then struck the ground.
The investigation
An examination of the engine by an FAA certificated mechanic found that a section of the intake gasket at the no. 3 cylinder assembly was missing. This defect allowed unmetered air to enter the cylinder, creating a lean fuel/air mixture.
Upon removal of the no. 3 cylinder, the top compression ring and oil control ring in the piston land were found to be immobile. The condition of the top of the piston and the cylinder corroborated the presence of a lean mixture.
Records indicated that the pilot had noted high cylinder head temperature (CHT) several months prior; however, it was determined at that time that the CHT probe, which is installed on the no. 3 cylinder, was broken. Additionally, a review of the engine logbook showed that the intake gaskets had been replaced on December 5, 1991.