What happened
On July 27, 2002, a Cessna T210N, registration OB-1261, operated by Cielos del Oriente, was performing a commercial flight from Atalaya to Pucallpa. While climbing through approximately 6,000 feet, the engine suddenly failed. The pilot attempted to restart the engine while selecting an emergency landing site, but the attempts were unsuccessful.
The pilot decided to perform a forced landing at the Bolognesi aerodrome, located roughly four minutes away. During the final descent, the aircraft struck trees and bushes approximately 12 and 0 meters from the runway threshold. The impact caused the tail section to detach from the fuselage. Despite the significant damage to the airframe, the pilot and five passengers were uninjured and evacuated the aircraft via both doors.
The investigation
CIAA investigators examined the Teledyne Continental TSIO-520-R(6) engine and the failed component. Laboratory analysis of the fuel pump coupling (P/N 631683) conducted by the Pontificia Universidad Católica del Perú revealed that the part had suffered a low-load flexural fatigue fracture.
The metallurgical analysis showed that the fractured coupling exhibited higher hardness throughout its section and surface compared to a new sample. Additionally, the surface showed micro-cracking and a decarburized layer, which was not present in the new specimen. This increased hardness likely made the component more sensitive to stress concentrators, such as machining defects or scratches, thereby reducing its fatigue life.
Findings
- The primary cause of the engine failure was the in-flight fatigue fracture of the coupling connecting the engine accessory gearbox to the mechanical fuel pump, which led to fuel starvation.
- The pilot failed to follow the specific engine failure and emergency landing procedures outlined in the Pilot's Operating Handbook (POH) and Airplane Flight Manual.
- The aircraft's landing gear was retracted at the time of impact.