What happened
On April 23, 2007, at approximately 19:30, a single-seat Rans S 9 Chaos ultralight, registration 61-IJ, was performing a local circuit at Flers aerodrome. The pilot, a 63-year-old individual with approximately 600 total flight hours, departed from runway 24.
Two instructors observing from the aerodrome airfield reported maintaining visual contact with the aircraft at an estimated altitude of 700 feet. During the final approach, the witnesses lost sight of the aircraft due to their position on the ground, only to regain visual contact as the aircraft flew over the runway at a very low altitude. At that time, the engine was noted to be running at a moderate RPM.
After passing the end of the runway, the aircraft entered a steep climb with a significant pitch attitude. The aircraft then turned right toward the runway, where it experienced a stall and impacted the ground approximately 40 meters north of the runway centerline. The witnesses noted that there was no audible increase in engine power during the final maneuvers.
The investigation
The investigation focused on the wreckage and the flight path observed by witnesses. Examination of the accident site and the aircraft debris indicated that the Rans S 9 Chaos struck the ground in a vertical, full-nose-down attitude.
Technical analysis of the aircraft's controls revealed no mechanical anomalies or malfunctions. While the engine was producing power at the moment of impact, the exact power setting could not be precisely determined. The investigation was unable to establish a definitive cause for the loss of control.