What happened
On July 26, 2018, a private flight in an SZD-9 bis 1 E Bocian glider, registration D-4 and 033, was conducting a local flight near Falköping Airport in Sweden. After a winch launch reached 500 meters, the pilot utilized a thermal to climb to 600 meters. As the thermal dissipated, the pilot began searching south for new lift, but a continuous loss of altitude necessitated a landing.
While executing a right-hand landing pattern for runway 22, the aircraft was at an altitude of 100 meters during the downwind leg, maintaining an airspeed between 60 and 65 km/h. As the aircraft crossed the touchdown point at 50 meters, the pilot initiated a turn onto the base leg at an altitude of 40 meters. During this maneuver, the aircraft rapidly lost altitude and struck the ground. Witnesses, including experienced flight instructors, observed the pilot raising the nose just as the turn began, which triggered a spin. The impact caused substantial damage to the aircraft and resulted in serious injuries to the pilot, specifically multiple leg fractures.
The investigation
The Swedish Accident Investigation Authority (SHK) analyzed flight data recorder logs, which recorded the aircraft's position and altitude every four seconds. The investigation also included interviews with the pilot and witnesses, as well as an assessment of the aircraft's flight characteristics. The investigation noted that the SZD-9 bis 1 E Bocian is a vintage design constructed from wood, which lacks modern crashworthiness features, leaving the cockpit area vulnerable during impacts.
Findings
Data from the GPS logs revealed that the aircraft was flying at speeds near its stall speed throughout the landing pattern. Furthermore, the altitude maintained during the pattern was approximately half of the minimum altitude required for a standard landing procedure. The investigation identified that the landing attempt was continued despite insufficient altitude and airspeed.
Contributing factors included the possibility that the high ambient temperature of 29°C may have led to pilot dehydration, potentially impairing decision-making. This may have prevented the pilot from adjusting the landing procedure to account for the low altitude. The aircraft's inherent stall and spin characteristics meant that the combination of low speed and a high angle of attack during the turn made the aircraft highly susceptible to entering a spin.