What happened
On October 1, 2005, a private Cessna 172 E, registration D-ELFH, was conducting a local flight departing from Cuatro Vientos Airport. The flight, intended to last approximately 1 hour and 45 minutes, included several simulated engine failure exercises near Talavera.
While flying near the Rosarito reservoir, the pilot initiated a turn to return to the departure point. During this maneuver, the engine experienced two fluctuations in RPM before suffering an instantaneous failure, accompanied by a strong smell of fuel. At an altitude of approximately 1,000 feet, the pilot identified an open field for an emergency landing. The aircraft touched down with 30° of flaps deployed, traveling approximately 110 meters along a path before turning and coming to a stop. Shortly after the aircraft came to a halt, a fire broke out, consuming the cockpit and much of the fuselage.
The investigation
The investigation focused on the cause of the engine failure and the subsequent fire. Investigators examined the wreckage and the fuel system components. While the engine and propeller sustained high temperatures, they did not burn. The fire was found to have originated at the firewall and moved toward the cockpit.
Evidence indicated that the fire started before the fuel filter. Specifically, the line connecting the gascolator to the fuel distributor/selector valve assembly was burned precisely where it passed through the firewall, suggesting that fuel was present in that line during the fire. The investigation also reviewed maintenance records, noting that while required inspections were up to date, the specific inspection of these connections was not due until the next major overhaul, which was over 1,600 flight hours away.
Findings
- The engine failure was caused by a sudden interruption of the fuel supply.
- Evidence suggests a massive fuel leak occurred at one of the connections involving the fuel distributor valve, which manages fuel from the tanks to the rest of the circuit.
- The sudden loss of fuel supply was likely due to a connection loosening at the distributor valve or one of the lines leading from the tanks to said valve.
- The post-landing fire was caused by the ignition of spilled fuel, likely ignited by a hot component of the engine.
- Both the pilot and the passenger survived the emergency landing with no injuries.