Collision du Ka-2b avec un câble près de Schafberg, Pontresina, Suisse

Le 5 août 1963, un Ka-2b Rhönschwalbe est entré en collision avec un câble d'un téléphérique à matériaux près de Schafberg, Pontresina, Suisse. L'incident s'est produit peu après que le planeur ait été largué à environ 250-300 mètres au-dessus de l'aérodrome de Samedan. Le câble, faisant partie d'un téléphérique utilisé pour le contrôle des avalanches, n'était pas marqué et difficile à voir sur le fond de la montagne. Malgré la collision, les deux occupants sont restés indemnes, bien que le planeur ait été détruit et que le téléphérique ait subi des dommages mineurs.

1. Aerotow ridge entry: The Ka-2b launched by aerotow from Samedan and was towed directly into the Val Bernina along the valley-side slopes at heights in places well below the standard 150 m minimum over the terrain.
2. No obstacle briefing: Before the flight, neither the instructor nor the student reviewed the posted local obstacle chart, so the existence and approximate position of the Pontresina–Schafberg material cableway remained unknown to them.
3. Low ridge flight height: During the tow into the valley and along the slopes, the tug and glider operated at relatively low height above the hillside, reducing vertical clearance from any unseen obstacles.
4. Tow release near Schafberg: At about 250–300 m above Samedan, near the lower Schafberg slope opposite Pontresina, the instructor released from tow to continue independent ridge soaring in what he believed was a steady 3 m/s updraft.
5. Closer ridge approach: After release, the instructor slightly reduced airspeed and flew the glider closer to the Schafberg slope, maintaining more than 50 m clearance from the ground but without awareness of any overhead cables.
6. Cable impact and spin: With the cable still unseen by the instructor and only noticed moments before by the student, the left wing struck the unmarked ropeway support cable, causing the glider to yaw and roll left and enter a spinning descent into the trees.
7. Crash - no injury: The glider fell through approximately 20 m high larch trees to the ground and was destroyed, while both occupants remained uninjured and the ropeway sustained only minor damage.