What happened
On May 9, 1999, a Piper J3 C 65 Cub, registered F-BCPK, was conducting a flight from Amiens toward Blois. The pilot had planned an intermediate stop at Chartres to refuel before continuing to the final destination. During the flight approach to Chartres, the pilot noted engine misfires that progressively worsened.
In response to the deteriorating engine performance, the pilot elected to perform an emergency landing in a nearby field near Coltainville. During the landing sequence, the aircraft encountered a rut in the terrain, causing the landing gear to collapse and the aircraft to flip onto its back. The two persons on board escaped without injury.
The investigation
The investigation focused on the cause of the engine failure and the condition of the fuel system. Investigators examined the fuel delivery components, specifically the connection at the fuel tank. Upon disassembly, the fuel line connection was found to be blocked by a mass of oxidized metal and silicone.
Further inspection of the fuel tank revealed significant internal corrosion. The strainer at the fuel tank outlet was found to be in poor condition, and the fuel filter downstream of the connection was missing entirely.
Findings
- The engine failure was caused by the obstruction of the fuel line by impurities located between the fuel tank outlet and the fuel filter housing.
- The fuel tank interior exhibited heavy corrosion.
- The fuel strainer was in a degraded state.
- The fuel filter downstream of the tank connection was absent from the system.
- The aircraft sustained damage to the propeller, engine cowling, and wing struts during the inversion.