What happened
On April 13, 2008, an AVEKO VL-3D1 Sprint ultralight aircraft was conducting a flight test near Kückhoven, Germany. The flight was part of a provisional type approval process. On board were the pilot, who was also the aircraft owner, and a flight instructor acting as a test observer.
After departing Kückhoven, the aircraft flew north for approximately 15 minutes before turning back toward Aachen. Radar data indicated that at 14:25, the aircraft's altitude dropped from 1,700 ft to 900 ft MSL within 40 seconds, accompanied by a change in heading. By 14:30, the aircraft's ground speed had decreased from 100 kt to 50 kt. Witnesses observed the aircraft entering a spin and descending toward the ground from an estimated altitude of 150 m. Although the pilot deployed the emergency parachute system, the aircraft struck the ground at a shallow angle, resulting in the destruction of the aircraft and two fatalities.
The investigation
The BFU examined engine monitoring data, radar tracks, and the wreckage. Analysis of the engine monitoring instrument revealed a sudden change in engine RPM, where the power surged to full load for six seconds before dropping to idle. The investigation also focused on the deployment of the Galaxy GRS-6/473 SD rescue system. Investigators found that the parachute system was activated at an altitude of only 65–70 m above ground, which was insufficient for full deployment during a spin. Furthermore, the investigation reviewed the pilot's experience, noting he had only 1 hour and 18 minutes of flight time in this specific aircraft type.