What happened
On October 10, 2003, a Cessna 210L, registration PT-IKM, was performing a flight from Belém to Limoeiro do Ajuru, Brazil. Approximately 17 minutes into the flight, while cruising at 2,500 feet, the pilot noticed engine oscillations accompanied by a drop in oil pressure and an increase in engine temperature. Shortly thereafter, the engine ceased operation.
The pilot executed emergency procedures according to the aircraft's checklists and performed a controlled emergency landing on a small sandbar within the Pará River. The aircraft's landing gear was retracted during the maneuver. While the aircraft sustained severe damage to the engine and right wing, the pilot and the three passengers were uninjured.
The investigation
CENIPA's investigation focused on the mechanical failure of the engine. An inspection of the engine revealed that the failure was caused by a lack of lubrication in the crankshaft main bearing area. The lack of lubrication led to excessive temperatures, which caused metal fusion that obstructed the oil flow passages.
Investigators found that the engine had very little residual oil in the crankcase and no traces of oil leakage on the engine casing. Although the engine had over 500 hours of useful life remaining, the investigation noted that this engine type tends to increase oil consumption as it ages. The investigation also found that there were no records of oil replenishment in the aircraft's logbook outside of scheduled maintenance, and it could not be confirmed if the pilot had checked the oil level during the pre-flight inspection.
Findings
- Lack of lubrication in the engine bearings was the primary cause of the engine failure.
- Failure to monitor and record oil consumption/replenishment prevented the identification of a low oil level.
- Management oversight allowed a culture where discrepancies and corrections were not being recorded in the aircraft logbook.
- The pilot's failure to verify the oil level during pre-flight preparations was a contributing factor.