Accident Sequence
The airplane was maneuvering at low altitude when the engine lost power. The pilot executed a forced landing onto a rough, uneven road. During the landing roll, the right main tire exited the road surface and entered a muddy ditch. The airplane subsequently nosed over in the adjacent soft field.
Investigation Findings
Postaccident examination revealed that the #1 cylinder intake valve rocker assembly stud bolt had backed out of its hole by four turns. This condition rendered the intake valve inoperative. The investigation noted that Lycoming Service Bulletin 412B, issued March 1978, called for replacement of all rocker arm retaining studs with oversized studs. That bulletin had been complied with at the factory before engine serial number L-7296-76 was shipped to Cessna in 1979.
Maintenance History
The airplane's original logbooks were reported lost, preventing verification of the engine's complete history. However, a review of reconstructed logbooks revealed that on February 12, 1998, the engine had accumulated between 200 and 300 hours since its last major overhaul. A 100-hour inspection entry dated September 24, 1998, noted that the #1 cylinder had been removed, honed, and fitted with new rings. A compression check at ground run showed 68/80, and the engine was determined to be in an airworthy condition at that time.