What happened
On July 15, 2010, at approximately 09:45 local time, a PIPER PA-36-375, registration EC-CUX, was performing agricultural spraying operations over a rice field at Finca El Pericón in Vejer de la Frontera, Cádiz. The aircraft, operated by Trabajos Aéreos Espejo, S.L., was conducting its eighth flight of the morning when the pilot initiated a left turn to begin a new application pass.
During this maneuver, the engine suffered a sudden and total loss of power. The pilot attempted to restore power by activating the electric fuel pump, but the engine failed to restart. In an effort to reduce weight and facilitate an emergency landing, the pilot released the remaining payload of approximately 600 kg. While attempting to reach a nearby path for an emergency touchdown, the aircraft struck three low-voltage power lines. This impact altered the aircraft's trajectory, causing it to strike the side embankment of the intended landing area. The aircraft slid approximately 40 meters before coming to a stop. The pilot sustained minor injuries and was able to exit the aircraft independently.
The investigation
The CIAIAC investigation focused on the cause of the engine failure and the circumstances leading to the crash. Investigators examined the engine, fuel systems, and the aircraft's operational procedures. The engine and its components, including the fuel pump and mechanical systems, were tested on a test bench and found to be in satisfactory working condition. No blockages or leaks were found in the fuel lines.
Regarding the fuel levels, investigators found very little fuel in the right tank and approximately 20 liters in the left tank. The investigation also reviewed the pilot's experience, noting that while highly experienced in other aircraft types, the pilot had only 25 hours of flight time in the PIPER PA-36-375. Furthermore, the investigation looked into the operator's manual and fuel management practices.
Findings
- The engine failure was caused by fuel exhaustion.
- The pilot relied on fuel consumption estimates from a different aircraft type (the Piper PA-25), which had a significantly lower fuel consumption rate than the PIPER PA-36-375.
- There was no established written procedure or flight plan used to accurately estimate fuel requirements or manage remaining fuel during repetitive, short-duration agricultural sorties.
- The operator's manual lacked specific guidance for managing fuel during agricultural spraying operations.
- Fuel asymmetry between the tanks likely occurred due to the aircraft's use of a sloped takeoff strip and frequent uncoordinated left-hand turns, which caused fuel to shift toward the left tank.
- The aircraft's fuel gauge was noted to be inaccurate when the aircraft was on the ground, potentially providing a false sense of security regarding remaining fuel levels.