What happened
On July 9, 2008, at approximately 12:12 UTC, an Extra 300L, registration D-EMCK, was conducting a low-altitude aerobatic training flight near Cabo Raso, Portugal. The pilot, an experienced aviator, had departed from Tires aerodrome to perform vertical development maneuvers. During a series of maneuvers, including aileron rolls and split-S transitions, the engine unexpectedly stopped.
The pilot immediately executed in-flight restart procedures, checking the magnetos, mixture, and fuel selector. When the engine failed to restart, the pilot was forced to perform an emergency landing on the N247 road near Guincho. While the pilot attempted to avoid obstacles such as lighting poles, the aircraft struck three parked cars on the roadside, causing the aircraft to skid and spin for approximately 30 meters. The pilot exited the aircraft uninjured.
The investigation
The GPIAAF investigation focused on the engine's performance and the fuel system status. The engine, a Lycoming AEIO-540L1B5, was subjected to static testing and was found to operate normally on a test bench. The ignition system and fuel selector valve were also inspected and found to be functioning correctly.
Investigators examined the fuel levels, noting that the aircraft had been refueled the previous day. While there was no official record of the most recent refueling, the pilot's flight plan indicated an expected endurance of one hour. Post-accident inspections of the central/acro tank revealed it was empty, and no leaks were detected in the lines or the tank itself. However, fuel spillage was observed under the right wing, which was caused by the destruction of the wing tank upon impact with a vehicle. This spillage confirmed that the wing tanks were not empty, despite instructions stating they should be drained for aerobatic flight.
Findings
- The engine experienced an unintentional in-flight failure.
- The primary cause of the engine stoppage was presumably fuel starvation.
- The aircraft's wing tanks contained residual fuel, which contradicts the requirement to keep them empty during aerobatic operations.
- The aircraft sustained significant damage, including a detached right wing, damaged fuselage, and broken landing gear.
- The pilot's proficiency in managing the emergency prevented fatalities and limited the damage to the aircraft and parked vehicles.