What happened
On April 6, 2012, an Embraer EMB-711C, registration PT-NKJ, was conducting a private flight originating from Patos de Minas, MG. The pilot intended to overfly a local farm before returning to the departure airfield. Approximately 40 minutes into the flight, while cruising at 4,500 feet, the pilot heard a loud noise and observed that the engine oil pressure indicator had dropped to zero.
In response to the engine failure, the pilot executed an emergency landing in a garlic plantation. The aircraft's trajectory was approximately 90 degrees offset from its original flight path. Following the impact, the aircraft slid for about 100 meters before coming to a stop. The pilot was uninjured, though the aircraft sustained substantial damage to the engine, propeller, right wing, horizontal stabilizer, landing gear, and engine cowling.
The investigation
CENIPA investigators examined the engine components at a maintenance facility in Brasília, DF. The inspection revealed a catastrophic failure of the number 3 cylinder. Investigators identified a fatigue crack in the combustion chamber region of the cylinder wall, where combustion gases had leaked. This leak initiated the fatigue, which eventually propagated through the cylinder head, leading to the separation of the cylinder sleeve.
Furthermore, the investigation found evidence of low compression in the remaining cylinders, which could have independently caused a loss of engine power. The investigation also noted that the aircraft's maintenance had been performed by non-certified workshops. Additionally, investigators were unable to establish the origin or traceability of parts used in recent engine services, including a replacement of the failed cylinder that had occurred in March 2010.
Findings
- Inadequate maintenance of the aircraft by non-homologated workshops.
- A catastrophic failure of the number 3 cylinder due to fatigue-induced rupture.
- Lack of traceability for engine components used in previous maintenance tasks.
- Evidence of low compression in other engine cylinders.
- The pilot failed to follow the aircraft checklist by not cutting the engine via the fuel cutoff lever during the emergency landing, opting only to close the fuel selector.