What happened
On July 17, 2018, a Cessna 182, registration G-BHYA, was performing a private flight from the Les Rabassières airfield for a scheduled annual maintenance visit. During the takeoff roll on the unpaved runway, the pilot rotated the aircraft after approximately 200 meters of ground roll. Immediately after the nose wheel lifted, the engine suffered a total loss of power at an estimated speed of 55 to 60 knots.
The pilot attempted an immediate emergency landing, maintaining the runway centerline. However, as the aircraft reached the end of the runway, it encountered tall grass and thick brush. The resistance from the vegetation caused the aircraft to decelerate sharply, leading to a nose-over accident where the aircraft overturned onto its back.
The investigation
The investigation focused on the cause of the engine power loss and the condition of the fuel system. Investigators examined the fuel circuit, which includes two flexible tanks, a fuel selector, a strainer, and both mechanical and electric pumps. The engine was also inspected, specifically the carburetor and ignition components.
Laboratory analysis of the carburetor revealed significant contamination. Debris, including metallic particles ranging from 0.5 to 0.8 mm and various multicolored fragments (potentially paint, sealant, or elastomers), was found within the carburetor filter and the check valve housing. The investigation also noted that the propeller governor's assist spring was improperly installed, though this was not determined to be the cause of the power loss.
Findings
- The investigation established that debris had contaminated the fuel system up to the carburetor, despite the presence of upstream filters.
- The presence of these particles likely interfered with the carburetor's operation, causing the observed engine power reduction.
- A significant imbalance in fuel weight between the two wings was noted, as the right tank contained 120 liters while the left tank was nearly empty. This asymmetry, combined with the pitch change during rotation, may have contributed to a fuel starvation event by causing the fuel level to drop below the intake orifice.