What happened
On May 10, 2008, at approximately 17:00 UTC, a Polaris FK 14 ultralight, registration F-JFFB, departed from an improvised dirt runway near Coriscada, Portugal. The aircraft was operated for a private flight with the pilot and one passenger on board.
During the initial climb, after reaching 300 feet AGL, the pilot retracted the flaps and initiated a left turn to complete a circuit. While entering a crosswind component, the aircraft encountered a wind gust. In an attempt to maintain the climb and compensate for the wind, the pilot applied right rudder while maintaining left and aft elevator input. This combination of controls induced a sideslip (glissade), which increased the rate of descent. The aircraft subsequently struck the canopy of a pine tree, causing the tail to impact the tree before the aircraft struck the ground 3/4 of the way through the maneuver. A post-impact fire broke out, destroying the aircraft. The pilot managed to exit the wreckage and release the passenger before the fire consumed the plane.
The investigation
The GPIAAF investigation examined the aircraft's maintenance history, the pilot's experience, and the environmental conditions at the time of the accident. The investigation noted that the aircraft's documentation and the pilot's logbook were destroyed in the fire, but maintenance records from a mechanic in Santa Cruz were recovered. The investigation also analyzed the takeoff performance on the improvised runway, which measured 175 meters in length, slightly shorter than the 185 meters required by the manufacturer for standard conditions.
Findings
- The pilot utilized a flap setting of position 2 for takeoff, a configuration discouraged by the flight manual due to high drag, which prevented the aircraft from gaining sufficient airspeed.
- The pilot's control inputs during the turn—applying right rudder while maintaining left and aft elevator—resulted in a sideslip that accelerated the descent.
- The takeoff runway was shorter than the manufacturer's recommended distance for the aircraft's weight and configuration.
- The pilot sustained a broken foot, and the passenger sustained broken legs.
- The aircraft was destroyed by the post-impact fire.