What happened
On September 8, 2002, a Robin DR 400-120, registered F-GOVN, was performing a local flight departing from Nantes aerodrome, with a planned stop at Mauléon. Approximately twenty minutes into the flight, the engine ceased operation. The pilot attempted to restart the engine and succeeded briefly, but the engine failed again. Despite applying the carburetor heat and attempting further restarts, the engine would not maintain operation.
After notifying the Nantes air traffic controller of the emergency, the pilot began an approach to a nearby field at approximately 2,000 feet. During the maneuvering, the engine briefly restarted each time power was applied. During the final approach, the aircraft flew too low and struck the safety barriers of a national highway, which sheared off the right landing gear. The aircraft then struck a fence before coming to rest in a field. The accident resulted in two fatalities.
The investigation
Investigators examined the Lycoming O-235-L2A engine to determine the cause of the power loss. The inspection revealed that the fuel pump discharge nozzle jet had been broken prior to the impact. While engine tests demonstrated that the engine could operate at a stabilized RPM even without this specific jet, its absence was noted.
Furthermore, investigators found that the carburetor vent was obstructed by foreign objects, specifically an insect fragment and a seed. Although a mandatory airworthiness directive required the installation of a fine 1mm mesh screen on the heated air intake, and this screen was present, the obstruction still occurred.