What happened
On September 11, 2006, a private CESSNA FR-172J, registration EC-DED, departed from Castellón Aerodrome for a local pleasure flight with a pilot and three passengers. Approximately two hours into the flight, while cruising at 1,500 feet over the mouth of the Mijares River, the engine suddenly stopped. The pilot notified Castellón Aerodrome and initiated a descent to attempt an emergency landing in the dry riverbed.
During the descent, the pilot attempted to restart the engine by engaging the auxiliary pump, setting a rich mixture, fine propeller pitch, and 1/2 throttle. While the engine successfully restarted and the pilot notified the airfield of his intention to return to the field, the engine failed a second time once the aircraft leveled off.
Faced with a second engine failure, the pilot opted for an immediate emergency landing on a nearby flat area. While attempting to reduce speed using full flaps to avoid a small earthen embankment at the end of the landing site, the aircraft made several contacts with the ground. The aircraft bounced and slid across the terrain in three distinct stages before finally coming to a stop against the embankment. All four occupants evacuated the aircraft without injury.
The investigation
Investigators examined the wreckage and the engine components to determine the cause of the sudden loss of power. The engine, which had only 2/52 flight hours since its last scheduled maintenance, showed no signs of mechanical malfunction, electrical failure, or air intake obstruction. Tests on the magneto system, ignition quality, and the auxiliary fuel pump all yielded satisfactory results.
Upon inspecting the fuel system, investigators found that the left tank contained 52 liters of fuel, while the right tank was completely empty. While the fuel selector valve was found in the "both" position, testing revealed that the fuel pump could only supply the engine from the left tank via gravity if the auxiliary pump was active; the right tank could not supply the main pump under gravity alone. No significant water contamination was found in the remaining fuel.
Findings
- The engine and its primary systems, including the ignition and air intake, were functioning correctly.
- The right fuel tank was empty at the time of the accident.
- The engine failure was caused by fuel exhaustion, likely due to the fuel selector valve being inadvertently set to the right tank or a partially intermediate position that allowed the right tank to drain without the pilot noticing.