What happened
On July 18, 2002, at approximately 17:40 local time, a Cessna 310-R, registration EC-EAH, performed an emergency landing in a field of orange trees near San Javier, Murcia. The aircraft, which was performing aerial photography operations, had departed from Zaragoza earlier that day with an initial destination of Valencia.
During the flight, the pilot requested an extension of the flight plan and changed the destination to Murcia/San Javier. While proceeding on the left base leg for runway 05, the pilot declared an emergency via radio. The aircraft subsequently struck several trees and came to a stop after impacting a perimeter fence. The impact resulted in one serious injury to the pilot and one minor injury to the photographer. The aircraft was destroyed.
The investigation
The investigation focused on the sequence of engine failures and the fuel state of the aircraft. Investigators examined the fuel selector valves, which were found in a configuration where the left engine was drawing from the left main tank, while the right engine selector was in an intermediate position between 'off' and the left main tank.
Physical inspections of the fuel tanks revealed that the left main tank was completely empty, while the right tank contained only a negligible amount of fuel. Detailed examination of the fuel lines and filters for both engines showed that the lines were dry, with only trace amounts of fuel found in the left engine's components. Tests conducted with a similar aircraft confirmed that once fuel is cut off, engines stop within seconds as the remaining fuel in the lines is consumed. The investigation also noted that the aircraft's maximum takeoff weight limitations, combined with the weight of the photography equipment and crew, restricted the total fuel load to approximately 560 liters, significantly less than the aircraft's 7-67 liter capacity.
Findings
- The primary cause of the engine failure was fuel exhaustion.
- Both engines were drawing from the left main tank at the time of the failure.
- The pilot's desire to complete the photography mission led to an extended flight duration that exceeded the safe fuel reserves.
- The fuel quantity indication system, which relies on a float and potentiometer, provided low-precision readings that were not sufficiently verified by the crew.
Safety action
- Pilots and operators of general aviation aircraft equipped with imprecise fuel indication systems should implement alternative and complementary methods to verify fuel quantity beyond relying solely on cockpit instrument readings.