What happened
On August 6, 2010, an EMB-810C, registration PT-RMX, operated by Piquiatuba Táxi-Aéreo Ltda., departed from the Piquiatuba aerodrome in Pará, Brazil, bound for Santarém for refueling. Shortly after takeoff, upon reaching an altitude of approximately 1,500 feet, the pilot heard a noise from the right engine, followed by a significant loss of power and airspeed.
In an attempt to return to the airfield via the opposite runway, the pilot executed a left turn. However, due to insufficient altitude and airspeed, and the presence of high-voltage power lines in the flight path, the pilot determined that a return to the runway was not possible. The pilot opted to perform a forced landing in a nearby plantation area. To maintain as much speed and lift as possible, the pilot retracted the landing gear and flaps. The aircraft struck the ground at an angle of approximately 15 degrees, dragging for 140 meters. The pilot emerged from the accident uninjured, though the aircraft sustained severe damage.
The investigation
CENIPA investigators examined the wreckage and the engines. While the left engine showed no signs of malfunction, a detailed metallurgical analysis of the right engine's number 4 cylinder by the Institute of Aeronautics and Space (IAE) revealed that the cylinder head had separated from the cylinder body. The investigation focused on the maintenance history of the aircraft and the compliance with manufacturer service bulletins. Investigators also analyzed the aerodynamic characteristics of the aircraft, noting that the asymmetrical rotation of the engines (the right engine rotates counter-clockwise) creates a significant yawing tendency during an engine failure, which increases drag when compensated with the rudder.
Findings
- The primary cause of the engine failure was material fatigue in the number 4 cylinder of the right engine, which originated from corrosion pits.
- The failure to comply with Teledyne Continental Service Bulletin SB96-12 prevented the detection of the corrosion.
- The maintenance organization failed to properly supervise maintenance tasks, specifically regarding the partial implementation of Service Bulletin SB03-3, which requires borescope inspections.
- The lack of adherence to these service bulletins meant that the internal corrosion, which led to the fatigue fracture, went undetected during scheduled inspections.