What happened
On June 28, 1999, a Cessna 210L, registration PT-KST, was conducting a cargo flight transporting pupunha seeds from Aeroxingu to Gurupi. Approximately 45 minutes into the flight, at an altitude of 5,500 feet, the pilot detected a strong smell of burning oil followed by a significant drop in engine oil pressure.
Recognizing the imminent danger, the pilot prepared for an emergency landing in the forest canopy. Before the engine ceased operation, the pilot successfully contacted another aircraft, PT-EZI, providing GPS coordinates to assist in future rescue efforts. The aircraft subsequently performed a forced landing into the treetops. While the aircraft was a total loss, the pilot survived the impact uninjured.
The investigation
The investigation focused on the cause of the engine failure and the discrepancies found in the aircraft's maintenance records. Because the wreckage was located in a remote area, it could not be recovered until the river levels dropped four months later. The physical condition of the engine, damaged by extreme overheating and the impact, prevented a definitive conclusion regarding the exact origin of the oil leak.
However, an inspection of the engine revealed that the oil pan was empty and the exhaust port of cylinder number 6 showed heavy oil contamination and carbonization. There was also evidence of a groove inside cylinder number 6. Investigators also discovered that the aircraft's logbooks were inaccurate; flight hour records in the engine and propeller logs did not match the movement records at Altamira airport, suggesting that periodic inspections may have been delayed.
Findings
- The engine failure was caused by overheating due to a loss of lubricating oil.
- The primary cause of the oil loss is suspected to be a rupture of the oil ring in cylinder number 6, though a manufacturing defect or improper maintenance during a recent top overhaul cannot be ruled out.
- There was evidence of deficient supervision regarding the aircraft's maintenance records, as flight hours were not being recorded accurately, potentially masking the need for scheduled inspections.
- The pilot's emergency management was effective in communicating position, though the decision to land with the landing gear extended was technically incorrect for an unprepared surface.
- The pilot's decision to move far away from the crash site during survival efforts initially hindered the rescue team's ability to locate him.