Incident Hütter H-28 lors d'un atterrissage hors-piste à Eschert après le départ de Spreitenbach, 1 blessé dans une collision

Le 12 juin 1965, le pilote avait l'intention d'effectuer un vol de distance avec le planeur Hütter H-28 HB-223, reliant Spreitenbach au Chasseral. Lors de l'approche, il a rencontré des zones de descente importantes, rendant un atterrissage en dehors de la zone prévue à Eschert BE inévitable. En atterrissant, l'avion a heurté un poteau en bois d'une ligne téléphonique, subissant des dommages considérables. Le pilote a subi des blessures légères, tandis que les dommages au sol étaient négligeables. L'enquête a révélé que le pilote avait retardé le moment de l'atterrissage et que l'atterrissage n'avait pas été effectué de manière optimale.

1. Cross-country cruise: The pilot departed Spreitenbach by aerotow for a cross-country flight toward Chasseral and was cruising along the Jura ridges.
2. Extended downdrafts: While attempting to cross from Mont Raimeux toward Montoz, the glider encountered widespread downdrafts of 2–3 m/s that prevented further progress and eroded altitude.
3. Delayed landing decision: After first selecting a landing field near the Moutier–Gänsbrunnen road, the pilot decided not to use it and continued searching for lift without having other clear landing options in sight.
4. Low, slow final approach: On the eventual outlanding approach over built-up and uneven terrain, the pilot flew a shallow glide without airbrake or sideslip, apparently at too low an airspeed while focusing on minimum sink rather than best glide.
5. Late obstacle recognition: Shortly before an orchard at the edge of the chosen field, the pilot only then noticed an additional power line beyond the trees and pushed the nose down at the last moment to gain speed to clear it.
6. Wing strikes telephone mast: During the low approach over the orchard, the left wing struck a 9 m telephone-line mast about 20 cm below its top, breaking the mast and yawing the glider, which then hit the ground with the right wingtip and nose.
7. Crash - minor injury: The glider came to rest about 20 m beyond the mast under a power line with substantial structural damage, while the pilot sustained minor injuries and nearby telephone infrastructure and vegetation were slightly damaged.