H 101 Salto-Absturz während Kunstflugtraining auf dem Flugplatz Thun
Am 2. Oktober 1988 führte ein Pilot auf dem Flugplatz Thun in der Schweiz ein Kunstflugtraining mit einem Glasflügel H 101 Salto durch. Der Pilot versuchte, Trudeln zu fliegen, hatte jedoch Schwierigkeiten, sich aus einem rechts eingeleiteten Trudeln in etwa 500 Metern Höhe zu erholen. Trotz Bemühungen, die Kontrolle zurückzugewinnen, setzte das Segelflugzeug das Trudeln fort, bis es auf dem Boden aufschlug, was zum Tod des Piloten führte. Die Untersuchung stellte fest, dass das Flughandbuch keine klaren Anweisungen zur Trudelerholung enthielt, was zur Unfähigkeit des Piloten, sich aus dem Trudeln zu erholen, beigetragen haben könnte.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- Crash - fatal: Still in the right-hand spin, the Salto impacted the ground at Thun and was destroyed, fatally injuring the pilot.