Accident Sequence
During cruise flight, the engine suddenly emitted a loud pop sound and began vibrating violently. The pilot initiated a forced landing on a road. However, the intended landing spot had to be overshot because of a car present on the road. After touchdown, the available distance was insufficient to stop before the aircraft collided with a curb.
Engine Examination
Post-accident examination of the engine revealed that the #3 cylinder exhaust valve head had separated from its valve stem. A large hole was observed in the piston. The valve head itself was destroyed. No other anomalies were noted in the report.
Maintenance Records
Review of the maintenance records showed that the engine had accumulated 2,131 hours since the last major overhaul. Lycoming, the engine manufacturer, recommends a time between overhauls (TBO) of 2,000 hours for this engine model.