Crash du H 101 Salto lors d'un entraînement acrobatique à l'aérodrome de Thoune

Le 2 octobre 1988, un pilote effectuait un entraînement acrobatique dans un Glasflügel H 101 Salto à l'aérodrome de Thoune, en Suisse. Le pilote a tenté d'effectuer des vrilles mais a eu des difficultés à sortir d'une vrille à droite initiée à environ 500 mètres d'altitude. Malgré ses efforts pour reprendre le contrôle, le planeur a continué à tourner jusqu'à ce qu'il s'écrase au sol, entraînant la mort du pilote. L'enquête a noté que le manuel de vol manquait d'instructions claires pour la sortie de vrille, ce qui pourrait avoir contribué à l'incapacité du pilote à sortir de la vrille.

1. Aerotow aerobatic training: The pilot was aerotowed to about 1000 m AGL at Thun to practice aerobatic figures, specifically reversals and spins in the single-seat Salto.
2. Limited spin experience: Although experienced in military training spins, the pilot had never initiated spins himself in the PC-7 and had only limited time and spin experience on the Salto type.
3. Ambiguous spin guidance: The Salto flight manual and its supplements provided non-simple, non-unique instructions for spin recovery, allowing a range of elevator positions and warning about flat-spin risk without prescribing a clear, definitive recovery technique.
4. Right spin successfully entered: After several unsuccessful spin entry attempts and one left-hand spin, the pilot initiated a right-hand spin from about 500 m AGL which quickly settled into a relatively flat, steady spin.
5. Ineffective recovery attempts: During the ensuing right-hand spin the pilot tried various control inputs, including operating the airbrakes during the last two turns, but did not select the specific combination of full forward elevator and full opposite rudder needed to stop the spin.
6. Prolonged flat spin: The glider remained in a flat, stationary right-hand spin for approximately 6–7 turns, rapidly losing the remaining altitude without any sign of recovery.
7. Crash - fatal: Still in the right-hand spin, the Salto impacted the ground at Thun and was destroyed, fatally injuring the pilot.