What happened
On October 9, 2009, a Colomban MC-15 (registration F-PYNN) crashed shortly after departing from the Praia Verde airfield in Castro Marim, Portugal. The aircraft, a homebuilt experimental model, was being used for a training and verification flight following a recent inspection in France.
During the takeoff roll, the aircraft required nearly double the expected distance to reach rotation speed. Upon liftoff, the aircraft immediately began deviating to the right at a low altitude. The flight was characterized by a significantly reduced rate of climb and slow acceleration. Witnesses observed the aircraft performing an erratic maneuver, pitching its nose up before entering a steep dive and spiraling into the ground. The impact destroyed the forward fuselage and cockpit, and the pilot sustained fatal injuries at the scene.
The investigation
The GPIAAF investigation examined the aircraft's condition, the pilot's recent activities, and the mechanical state of the engines. Investigators noted that the aircraft had been stored for approximately four months prior to the accident. The fuel used for the flight had been a pre-mixed oil/gasoline blend prepared five days in advance.
Physical evidence from the wreckage revealed that the left engine's power lever had been retarded to idle and the ignition switch was set to the "OFF" position. The investigation also noted several instances of non-standard maintenance and amateurish installation of components within the aircraft, including unidentifiable power lever terminals and improvised electrical wiring.
Findings
- The primary cause of the accident was the pilot's loss of control at a low altitude due to engine failure, which led to a stall and subsequent spin.
- The pilot was experiencing high levels of fatigue and stress following a long-distance journey towing the aircraft and performing manual labor to clear vegetation from the runway prior to takeoff.
- The aircraft's engines were likely underperforming; the right engine may have suffered a complete stoppage, and the left engine was found in a shut-down configuration.
- Potential fuel issues contributed to the failure, as the fuel mixture had been stored for several days and there was no evidence that the fuel tanks or lines had been drained of potential contaminants or old deposits.
- The aircraft's takeoff configuration (flaperons set to takeoff position) was not changed before the impact occurred.