What happened
On November 15, 2014, an Aero Boero AB-115, registration PP-GPM, was conducting a cross-country navigation training flight from Lages (SBLJ) to Ponta Grossa (SSZW). The crew, consisting of an instructor and a student, was approximately 11 minutes into the flight when the engine experienced a sudden drop in RPM to 1500, followed by intense vibrations and total engine failure.
Upon the failure, the crew identified an available runway at the Regional Aeródromo do Planalto Serrano in Correia Pinto, SC. This airfield was under construction at the time and was not listed in the ROTAER. The crew successfully performed an emergency landing on this strip. While the two occupants escaped without injury, the aircraft sustained substantial damage to the engine.
The investigation
CENIPA investigators examined the aircraft and performed an initial inspection which revealed that the engine had seized. Specifically, the piston in the third cylinder was found to be immobile. To further investigate the cause of the in-flight failure, the engine was disassembled at an authorized maintenance facility under the supervision of SERIPA V investigators.
The disassembly revealed that the connecting rod for the third cylinder had broken. Other internal components were found to be sheared or fused. The engine components were subsequently sent to the Institute of Aeronautics and Space (IAE) for macroscopic analysis. The laboratory results confirmed that the materials exhibited damage and deformations consistent with overheating.
Findings
- The engine failure was caused by the breakage of the third cylinder's connecting rod.
- The breakage was a result of overheating within the third cylinder.
- The specific factors that led to the initial overheating of the cylinder could not be determined.