What happened
On September 21, 2012, an EMB-720D Neiva, registration PT-VIB, departed from Redenção, PA, en route to Macapá, AP. The aircraft was operated for private purposes with the pilot alone on board. Approximately forty minutes into the flight, while communicating with Carajás Radio, the pilot noted unusual engine noise and observed that the oil pressure had dropped into the red zone.
Shortly after notifying the radio that an emergency landing at Caraj．as Aerodrome was being attempted, the engine ceased operation. Unable to reach the intended airfield, the pilot performed a forced landing in a cleared area belonging to the mining company Vale do Rio Doce, located approximately 7.4 NM from Carajás Aerodrome. The pilot escaped the aircraft without injury, though the engine sustained internal damage.
The investigation
CENIPA investigators examined the Lycoming IO-540K1G5 engine at an approved workshop. Upon disassembly, investigators discovered a fracture in the engine block near the oil filler neck. Metal shavings were found inside both the oil filter and the oil strainer. Further inspection of the crankshaft revealed a fracture between the number 5 and number 6 connecting rods in the counterweight region.
Microscopic and stereoscopic examinations of the fracture surface revealed "beach marks," which are characteristic indicators of a fatigue process. While no evidence of corrosion was found, the origin of the fatigue could not be determined.
Crucially, the investigation identified a significant discrepancy in maintenance records. Although the engine had undergone a major overhaul in January 2009, the crankshaft found in the engine (P/N LW-17727, S/N U387) did not match the crankshaft documented in the overhaul paperwork. Furthermore, the installed crankshaft did not correspond to the parts catalog provided by the manufacturer, and there was a complete lack of traceability regarding when or how this specific component was installed in the engine.
Findings
- The engine failure was caused by a fracture of the crankshaft due to material fatigue.
- There was a critical lack of traceability regarding the installed crankshaft.
- The crankshaft installed in the engine was not the component that had been documented as inspected during the engine's last major overhaul.
- The installed component did not match the manufacturer's parts catalog.
- Maintenance of the aircraft was identified as a contributing factor.
Safety action
CENIPA issued a safety recommendation to the National Civil Aviation Agency (ANAC) to conduct a technical audit of the maintenance facility involved (Planave Aviação Ltda.). The objective of this audit was to analyze and propose improvements to the processes for receiving parts and managing maintenance records for engines and other aeronautical components.