Kranich III forced landing after tow release near Bex Aérodrome

On June 29, 1969, a DFS Kranich III took off from Bex Aérodrome with a pilot and one passenger. Shortly after takeoff, the pilot released the tow rope when the tow plane struggled to gain altitude. The glider performed a forced landing, resulting in significant damage to the aircraft. Both the pilot and passenger were unharmed. The investigation confirmed that the airbrakes were inadvertently deployed during takeoff, affecting the tow plane's performance.

1. Aerotow takeoff: The Kranich III HB-538 with a pilot and passenger began an aerotow takeoff from Bex airfield at 14:34.
2. Airbrakes extend: During the takeoff roll or initial climb, the glider’s airbrakes became deployed without the pilot noticing, increasing drag.
3. Undetected airbrakes: The pilot was unaware that the airbrakes were out, so the abnormal drag condition persisted during the climb.
4. Tow cannot climb: The additional drag from the extended airbrakes prevented the tow plane from gaining sufficient height after liftoff.
5. Tow rope released: Recognizing that the tow combination was not climbing, the glider pilot released the tow rope shortly after takeoff.
6. Hard landing - damage: The pilot carried out a forced landing near Bex, during which the glider was severely damaged but both occupants were uninjured.