Collision du K 8 B avec un câble près de Wolfenschiessen lors d'un vol d'entraînement

Le 7 juin 1976, un Alexander Schleicher K 8 B est entré en collision avec un câble de transport près de Wolfenschiessen, en Suisse, lors d'un vol d'entraînement. Le pilote, qui avait une expérience de vol limitée, volait à environ 60 mètres du sol lorsque l'aile droite a heurté le câble. L'impact a causé des dommages importants à l'aile et le planeur s'est écrasé, entraînant des blessures graves pour le pilote. L'enquête a noté une préparation de vol inadéquate et un non-respect de la hauteur minimale de vol comme facteurs contributifs. Le planeur a été détruit dans l'accident.

1. Aerotow ridge flight: The pilot aerotowed from Buochs and then ridge-soared up the northwest flank of the Buochserhorn to summit height before proceeding south along the east side of the Engelberg valley behind a lead glider.
2. Low experience pilot: The 18-year-old pilot had only 18:42 hours total time, limited solo experience on type, and was flying without instructor supervision under a short-term permit.
3. Poor obstacle planning: Before departure he did not study the obstacle chart or otherwise check for cables and other airfield obstacles along the intended route in the mountainous, obstacle-dense Engelberg valley.
4. Low ridge height: While following the lead glider along the valley side, he flew close to the slope at about 60 m above ground without having ensured there was no collision risk with obstacles.
5. Turn into lift zone: North of Chlei Gigi, upon noticing an area of lift, the pilot turned left toward the updraft area and immediately encountered an unmarked transport cable across his flight path.
6. Wing strikes cable: The glider passed just under the right-sloping cable but the right wing struck it about one metre inboard of the tip, tearing off a large outer wing section that remained hanging on the cable and causing the cockpit canopy to depart.
7. Crash - serious injury: Following the structural damage from the cable strike, the glider became uncontrollable and crashed near Chlei Gigi at about 1640 m elevation, seriously injuring the pilot and destroying the aircraft.