What happened
On June 1, 2008, at approximately 19:00 h, a Cessna F-177-RG «Cardinal», registration EC-BYT, was performing a local VFR flight near Pamplona, Spain. The pilot was executing a wide left base for runway 33 and had been cleared by the control tower for the final approach, maintaining an altitude of 2,800 ft.
During the approach, the engine suddenly lost revolutions, fluctuated erratically, and eventually ceased functioning. After an unsuccessful attempt to restart the engine, the pilot determined that attempting to reach the airport runway would be unsafe. The pilot identified a suitable cereal field, free of obstacles, for an emergency landing. After notifying the control tower of the situation and preparing the aircraft by cutting the fuel and disconnecting the magnetos, the pilot performed the landing with the gear extended.
The landing was heavy, causing the two main landing gear legs to retract. The aircraft slid approximately 140 meters on its nose gear, lower fuselage, and horizontal stabilizer before coming to rest on its left wing. The pilot sustained no injuries and exited the aircraft unaided.
The investigation
The investigation focused on the mechanical condition of the engine, fuel system, and the pilot's pre-flight procedures. Inspections of the wreckage and subsequent workshop analysis revealed that the engine, propeller, and electrical systems were in good working order. There were no signs of leaks, obstructions, or failures in the fuel lines, vents, or tanks. The propeller showed no deformation, indicating the engine was not producing power upon impact.
Investigators examined the fuel levels, noting that while some fuel remained in the right tank, only half a liter was present in the left tank. The investigation also reviewed the pilot's method of fuel management, noting that the pilot relied on personal consumption estimates rather than visual inspections of the fuel gauges.
Findings
- The engine failure was caused by fuel exhaustion.
- The pilot relied on estimated fuel consumption based on previous experience rather than performing the visual fuel quantity checks required by the Flight Manual.
- The pilot's fuel consumption estimates were not conservative and underestimated the actual fuel usage during certain flight regimes.
- The required pre-flight visual inspection of the fuel levels in both tanks was not performed prior to departure.