What happened
On 17 April 2021, at approximately 13:22 UTC, a Valentin Mistral-C sailplane was involved in an accident during a local, non-commercial flight departing from the Aerodrome of Cerfontaine (EBCF). The pilot, who had recently completed refresher training, intended to perform a solo flight in this specific aircraft type, which they had not operated previously. Following a briefing by a sailplane instructor and a standard pre-flight inspection, the aircraft was prepared for takeoff.
The takeoff was conducted via a tow from a Piper PA18-180 aircraft using runway 30L. As the sailplane accelerated and achieved lift-off, the aircraft began to exhibit a rhythmic, longitudinal pitching motion known as a porpoising movement. As this instability intensified, the pilot executed a release of the tow cable. Shortly after the release, at an altitude of approximately 15 meters, the sailplane entered a left-hand turn and descended into the ground. The impact resulted in one serious injury to the pilot's back and caused substantial damage to the aircraft.
The investigation
The AAIU(Be) initiated a safety investigation into the occurrence, utilizing several key evidence sources. Investigators performed a detailed inspection of the wreckage and analyzed witness statements provided by those present during the event. Additionally, data from the aircraft's FLARM recording system was examined to reconstruct the flight parameters during the takeoff sequence.