Atterrissage en campagne de l'ASW-15 dans un terrain difficile près de Rüschegg-Graben, Suisse
Le 7 mai 1972, un Schempp-Hirth ASW-15 a effectué un atterrissage en campagne près de Rüschegg-Graben, Suisse. Le pilote, participant à une compétition régionale, a rencontré des difficultés pour retourner à Berne en raison d'une désorientation et d'une panne de variomètre signalée. Le pilote a choisi d'atterrir dans un petit champ entouré d'obstacles, ce qui a entraîné un atterrissage dur endommageant le fuselage et l'empennage de l'appareil. Malgré les lourds dommages subis par l'ASW-15, le pilote est resté indemne et aucun dommage à des tiers n'a été constaté.
- Cross-country return leg: During the return leg of a Bern–Romont–Bern task, the pilot was flying cross-country in weak thermals under 4–6/8 cumulus with bases around 1400–1700 m.
- Disoriented near Bern: On the way back the pilot had difficulty locating the Bern airfield and drifted south of the intended course toward the Schwarzenburg area.
- Weak thermals, low height: In the Schwarzenburg area the pilot was at relatively low altitude in generally weak thermal conditions, limiting his options.
- Perceived vario failure: Near the shortwave transmitter at Schwarzenburg the pilot reported a temporary failure of the electric variometer, which he believed hindered his ability to exploit the weak lift, although a mechanical variometer remained available.
- Chooses small field: Recognizing his low height, the pilot decided to outland in a small 160 m field that was preceded by trees and a telephone line and bordered by an orchard and a solid fence.
- Long landing and ground loop: Despite using a sideslip and full airbrakes, the glider touched down only about 120 m into the field, and to avoid colliding with the fence the pilot forced the left wing onto the ground and executed a ground loop, bending the fuselage and damaging the tail.
- Outlanding - damage: The glider sustained severe structural damage in the off-field landing and ground loop, while the pilot remained uninjured and no third-party damage occurred.