Incident Overview
While en route to Birmingham, the pilot of a single-engine aircraft experienced a complete loss of engine power when the No. 2 cylinder separated from the engine assembly. The pilot attempted an emergency landing on Interstate 65 near Hanceville, Alabama. During the landing, the aircraft collided with an embankment adjacent to the southbound lanes.
Previous Maintenance Issues
The investigation revealed that the aircraft had experienced severe engine vibrations twice within the three months preceding the accident. On both occasions, the cylinders were overhauled and the aircraft was returned to service. The maintenance personnel who performed the repairs stated that they did not follow the procedures outlined in the engine service manual.
Investigation Findings
The failure to retorque and inspect the engine assembly caused the other cylinder studs to loosen, leading to the eventual failure of the No. 2 cylinder. The investigation determined that the improper maintenance practices directly contributed to the cylinder separation and subsequent power loss.