What happened
On August 6, 2022, a Schleicher Ka6 was performing a winch-assisted takeoff from Runway 11 at the Aerodrome of Tournai/Maubray. During the initial climb, the aircraft immediately adopted an excessively steep pitch attitude. As the sailplane ascended, it began drifting toward the left, likely due to a prevailing crosswind. In an attempt to correct this drift, the pilot maneuvered the aircraft, which caused the right wing to drop. This movement led to a stall of the right wing and transitioned the aircraft into a clockwise spin. At an altitude of approximately 100 meters, the aircraft completed one and a half rotations before impacting the ground. The impact destroyed the Schleicher Ka6 and resulted in 1 fatal injury.
The investigation
AAIU(Be) conducted a limited-scope investigation, examining the aircraft wreckage, flight control continuity, and meteorological conditions. Investigators found that all flight controls, including the elevator, rudder, and ailerons, were fully functional and continuous. The aircraft's weight and balance were within limits, and the correct weak link was utilized for the winch operation. The investigation also reviewed the pilot's recent flying experience and the specific technical characteristics of the Schleicher Ka6, noting that this was the pilot's first winch launch with this specific model.
Findings
- The primary cause of the accident was the exceeding of the critical angle of attack on the right wing following a pilot correction for leftward drift.
- The aircraft's steep climb angle and the low altitude at which the spin developed made recovery impossible.
- A potential contributing factor was an undetected incorrect elevator trim setting during pre-flight checks.
- The pilot's relatively low recent flying currency was identified as a risk factor.
Safety action
Following the occurrence, the local aeroclub implemented several safety measures, including the appointment of a safety officer and the introduction of systematic monitoring of pilot experience. The club also initiated new check flights for all pilots and integrated the use of a 'currency barometer' into daily briefings to manage operational risks.