What happened
On June 27, 1998, at 14:31, a Schleicher ASK 23 B glider, registration PH-8</strong>817, was performing a local winch launch at the Woensdrecht Airbase. During the ascent, the pilot perceived that the indicated airspeed was not increasing sufficiently, staying between 50 and 60 km/h. Believing the aircraft was failing to reach the necessary speed, the pilot decided to abort the launch at an altitude of approximately 5 to 10 meters.
Upon disconnecting from the winch cable, the pilot executed significant downward control inputs. This maneuver, followed by several overcorrections, caused the aircraft to strike the ground. The impact was severe enough to break the T-tail from the fuselage and cause a crack in the left wing-to-fuselage junction. The pilot sustained serious injuries to the back.
The investigation
The investigation examined the winch operations, the aircraft's mechanical condition, and the pilot's actions. The winch operator had been operating the Busio-type winch system according to standard procedures. While the operator relied on auditory and visual cues to manage speed, it was noted that the initial winch speed might have been insufficient for a single-seat aircraft.
Technical inspections of the PH-817's airspeed indicator and pitot-static system, conducted both before and after the accident, revealed no malfunctions. The aircraft was within weight limits and all airworthiness documentation was valid. Investigators also observed that the deployment of the winch parachute, triggered by the loss of tension in the cable, may have startled the pilot.