What happened
On April 27, 2012, an Embraer EMB-712, registration PT-RPT, was conducting a flight training mission between Salvador (SBSV) and Paulo Afonso (SBPF). The flight was operated by CFA Cursos Escola de Aviação Civil as a private flight (PRI).
During the return leg to Salvador, while descending through 4,0-00 feet at approximately 20 nautical miles from the destination, the crew observed a low oil pressure warning light. This was immediately followed by a significant drop in oil pressure and a complete engine failure. The pilot performed an emergency landing on the banks of the Rio Joanes dam, near São Sebastião do Passé, Bahia. The aircraft sustained substantial damage to the engine, the right wing, the right main landing gear, and the nose gear. Both the instructor and the student pilot were uninjured.
The investigation
CENIPA's investigation focused on the mechanical failure of the Lycoming O-360-A4M engine. While the aircraft's airworthiness certificate and maintenance logs were up to date, investigators identified a discrepancy in the engine's overhaul components.
Although the engine had undergone an overhaul in March 2010, the investigation found that the piston pin plugs used in the cylinders were part number 60828, rather than the mandatory part number 72198 required by Service Instruction 1267D. The analysis revealed that abnormal wear in the piston hole of the number two cylinder produced significant metal debris (swarf), which saturated the oil filter. Once the filter was saturated, contaminated oil bypassed the system, leading to insufficient lubrication of the number two cylinder's crankpin. This caused the observed damage and the eventual rupture of the cylinder block.
Findings
- Maintenance of the aircraft
- Managerial supervision