Accidente del Pilatus B4 en Schafberg resulta en fatalidad durante vuelo de entrenamiento

El 15 de agosto de 1981, un Pilatus B4-PC 11AF se estrelló en las laderas del Schafberg cerca del Blinnenhorn, Suiza. El piloto partió del aeródromo de Münster para un vuelo de entrenamiento y perdió el control del planeador, resultando en un accidente fatal aproximadamente a las 18:55 hora local. El planeador fue destruido al impactar, y el piloto, que tenía experiencia limitada en vuelo de montaña, falleció. La investigación no encontró fallas técnicas preexistentes en la aeronave, y las condiciones meteorológicas se reportaron como buenas con térmicas débiles.

1. Aerotow training flight: The pilot departed Münster/VS at 1515 local on an aerotow in Pilatus B4 HB-1566 for a solo mountain training flight and released the tow after about ten minutes.
2. Limited mountain experience: The pilot had low overall glider time and only a brief prior mountain-flying introduction and one earlier solo mountain flight in the accident type.
3. Weak, irregular thermals: In the accident area around the time of the crash, only weak, somewhat irregular thermals (“Nullschieber”) were present, allowing height to be maintained but not gained.
4. Entry to spin/spiral: For unknown reasons, the glider entered an uncontrolled right-hand autorotation, observed as a right spin or steep spiral.
5. Low-altitude rotation: The glider remained in the right-hand spin for about one to one and a half turns without recovery and descended toward the slope.
6. Crash - fatal: The glider impacted the rocky west slope of the Schafberg at approximately 2560 m, was destroyed, and the pilot was fatally injured.