What happened
The incident occurred while the aircraft was in flight over the ocean. The pilot observed that the engine was operating abnormally, noting unusual sounds and a complete loss of oil pressure indicated by the gauge dropping to zero. Shortly after these initial signs appeared, the engine began to vibrate violently before seizing completely.
With no power available, the pilot assessed the situation for a forced landing. Although highways were present in the area, traffic concerns led the pilot to choose an open field instead. The decision was made to execute an intentional wheels-up landing on upsloping terrain. This maneuver resulted in a hard impact with the ground.
The investigation
Post-accident examination of the engine revealed significant internal damage. Approximately two handfuls of metal flakes were discovered in the oil sump. The oil pump pickup screen was found to be clogged by these metal fragments. Notably, no metal flakes were present in the engine oil filter, suggesting the debris bypassed filtration or accumulated rapidly.
Further inspection identified that the number six connecting rod had failed and penetrated the engine case. Analysis of the evidence indicated that the failure sequence began with the breakdown of a connecting rod bearing. This initial bearing failure led to the subsequent connecting rod fracture and eventual engine seizure.
Findings
The engine had been operated for 23 hours since its most recent annual inspection at the time of the failure. The mechanical evidence points directly to an internal lubrication or bearing failure as the primary cause of the loss of power.