What happened
On the morning of October 23, 2008, a solo glider flight at the Haamstede glider airfield resulted in a hard landing. The pilot, operating a Schleicher ASK-13 with registration PH-449, performed a winch launch during sunrise conditions. Following the release of the cable, the aircraft repeatedly entered stalls. The pilot noted that the control stick could not be moved fully forward, a limitation he initially mistook for a characteristic of the aircraft type. To maintain stability at a speed of approximately 65 km/h, the pilot flew with the flaps partially open. Due to the low airspeed and high sink rate, the pilot avoided maneuvers to prevent a spin and instead entered the landing circuit at an altitude of roughly 350 meters. During a wide approach, the aircraft struck the upper branches of some bushes before landing heavily near a ditch. There were no injuries and no damage to the aircraft or the airfield.
The investigation
The investigation focused on the cockpit configuration and the pilot's pre-flight procedures. It was established that the pilot failed to perform the required pre-flight inspections. Specifically, the pilot did not check the seatbelts in the rear cockpit, nor did he remove the 15 kg ballast from the front seat that had been placed there by a previous instructor. Crucially, the investigation found that the rear control stick had been secured with a shoulder strap to prevent elevator movement during ground transport, a practice that had become common at the club due to a rubber covering on the front stick making it difficult to secure. The pilot failed to notice that this strap was still in place.
Findings
- The primary cause of the flight control difficulties was that the rear control stick was still secured with a shoulder strap, which physically prevented the front control stick from moving fully forward.
- The pilot failed to perform necessary pre-flight checks, which would have identified the obstructed control movement and the unremoved ballast.
- The pilot proceeded with the launch despite noticing the restricted movement of the control stick during the cockpit check, incorrectly assuming the limitation was a standard feature of the Schleicher ASK-13.