What happened
On July 29, 1973, a Kestrel HB-1001 glider was conducting a local flight at the Schänis airfield. Following a standard aero-tow and subsequent soaring flight, the pilot initiated the landing sequence on runway 35 shortly before 16:00. During the final stage of the approach, the aircraft contacted a patch of reeds located approximately 10 meters before the start of the paved runway. This contact caused the glider to veer left and lose altitude abruptly. The aircraft struck the ground roughly 8 meters short of the runway, at which point the left wingtip collided with a nearby road. The force of this impact induced a violent yaw to the left, resulting in the tail section and rudder detaching from the fuselage.
The investigation
The investigation examined the aircraft's condition, the pilot's experience, and the flight path. The Kestrel HB-1001 was found to be airworthy and properly registered, with the weight and center of gravity within permissible limits. No pre-existing technical defects were identified. The pilot, an experienced flyer with over 600 total flight hours, was found to have no relevant medical impairments. Witnesses observed that the aircraft appeared to have a steep glide angle and noted that the airbrake flaps were partially extended. Evidence at the scene showed landing gear tracks beginning approximately 2 meters after the reeds ended, and impact marks on the road confirmed the wingtip strike. While the pilot reported retracting the airbrakes in the final phase, witnesses noted the airbrakes remained extended following the impact.
Findings
- The primary cause of the accident was the aircraft flying too low during the final approach, which led to the collision with the reed bed.
- The pilot likely utilized the airbrakes too extensively or for too long a duration, creating a steep descent.
- The impact with the vegetation caused a sudden loss of lift and a directional deviation that led to the structural separation of the tail.