In-Flight Engine Failure During Visual Approach (N3074F)

Incident Overview and Flight Progression A pilot was conducting a visual personal flight when the aircraft received vectors for the runway 19 final approach course. Approximately two miles from the runway threshold, the pilot applied additional throttle. The engine initially responded but then continued to misfire. The pilot reported hearing a muffled explosion and observing a small puff of white and blue smoke from the right side of the engine cowling. The engine quit when the aircraft was about 1.5 miles from the threshold at 2,500 feet mean sea level. Because the altitude was insufficient to return to the airport, the pilot elected to land in an open vacant lot. The aircraft burst into flames after coming to rest. ## Maintenance Findings Examination of the engine revealed that during a recent top overhaul, mechanics installed the wrong connecting rod bolts that were improperly torqued. Additionally, the oil drain plug came loose while in flight, causing the engine to sustain a catastrophic failure. The investigation determined that the mechanics failed to safety the oil drain plug.