What happened
On February 3, 2004, at approximately 16:30, a Denney Kitfox MK2 ultralight, registration 68ADW, was conducting engine taxi tests at an airfield in La Rochebeaucourt-et-Argentine, France. The pilot had recently performed several engine adjustments and checks two days prior to the event. The intention of the flight was not to take off, but merely to test the Rotax 582 engine at maximum RPM during taxiing.
According to eyewitness accounts, the aircraft initially taxied in circles near the hangar before moving toward the threshold of runway 13. After traveling approximately 200 meters along the unpaved runway, the aircraft suddenly lifted off. The aircraft flew at an altitude of roughly ten meters before disappearing from view and crashing approximately 80 meters south of the runway end. The impact resulted in the destruction of the aircraft and left the pilot with serious injuries.
The investigation
The investigation focused on the aircraft wreckage and witness testimonies. Examination of the wreckage revealed that the aircraft struck the ground in a slightly nose-down attitude, pitched to the right. Evidence from the engine indicated that the engine was delivering low power at the moment of impact; specifically, the throttle lever was found stuck in the pulled position, and the butterfly valves of both carburetors were closed.
Witnesses provided conflicting but complementary observations regarding the engine state. One witness noted a decrease in engine RPM, which led them to believe the pilot was attempting to land, while a second witness observed the aircraft at a low altitude and low speed, noting that the engine appeared to be at idle. The pilot experienced amnesia regarding the period between arriving at the airfield and regaining consciousness at the hospital.
Findings
- The pilot was performing engine tests without having conducted a pre-start or pre-taxi checklist.
- The aircraft encountered the unintended takeoff likely due to the pilot's lack of familiarity with the specific runway profile, which features a convex shape and a significant rise in the middle.
- It is possible the pilot did not immediately attempt to land because they were unaware of the available runway length and terrain beyond the central rise of the strip.