What happened
On April 19, 2007, an Air Tractor AT502A, registration EC-ENM, was performing agroforestry operations near Vitoria, Spain. After completing its seventh flight of the day, the aircraft was returning to the Vitoria Airport following a fertilizer discharge. During the return leg, the pilot notified Vitoria Tower that the engine had stopped due to a lack of fuel and that an emergency landing outside the airfield was necessary.
The aircraft impacted a wooded area approximately 2.7 km north of Gordoa. The descent path, determined by damage to trees at the impact site, showed a 17-degree descent angle. The aircraft struck several trees before coming to rest in a 30-degree nose-down attitude. Despite the significant damage to the fuselage and wings, the pilot was able to exit the aircraft without injury.
The investigation
The CIAIAC investigation focused on the fuel system, recent refueling records, and the pilot's operational procedures. Investigators examined the aircraft's fuel tanks and found that while the wing tanks were empty, a small amount of fuel remained in the central tank—enough to reach the fuel filter but insufficient to reach the engine injectors.
Review of refueling logs revealed significant irregularities. Although the aircraft had been refueled in Vitoria on April 16, the amount recorded for that session actually exceeded the maximum capacity of the aircraft's tanks. Furthermore, the operator could not provide an explanation for these discrepancies or for the lack of fuel monitoring. The investigation also noted that the pilot's experience with single-engine turboprop aircraft was limited to only 16 hours.
Findings
- The primary cause of the accident was fuel exhaustion.
- Irregularities in refueling procedures occurred in the days leading up to the accident, including a recorded refueling that exceeded the aircraft's total fuel capacity.
- The pilot failed to perform adequate visual fuel checks, planning, or continuous monitoring of fuel levels during the flight.
- The pilot's limited experience with the specific aircraft type and its unique fuel management system contributed to the error.
- The aircraft's fuel system required the pilot to manually select which tank to monitor, a task that was not effectively managed during the operation.