Colisión del PZL Bielsko SZD-12A con un cable de transporte de heno cerca de Sächseln, Suiza
El 11 de julio de 1965, un PZL Bielsko SZD-12A colisionó con un cable de transporte de heno cerca de Sächseln, Suiza. El incidente ocurrió durante un vuelo de ladera cuando el planeador golpeó el cable aproximadamente a dos kilómetros al sur de Sächseln. El piloto resultó fatalmente herido y la aeronave fue destruida en el impacto. La investigación oficial concluyó que la colisión se debió a que el piloto voló en un área propensa a obstáculos sin reconocer el cable a tiempo.
- Aerotow — ridge flight: The pilot launched from Kägiswil at 17:34 for a training flight and, after about an hour soaring the slopes east of Sarnen, continued ridge flying southwest along the Arnigrat in the evening.
- Decreasing evening lift: As the evening progressed the ridge lift weakened, requiring flight increasingly close to the slope to maintain altitude.
- Low clearance near terrain: While ridge soaring near the northwest face of the Arnigrat, the glider was flown at a small lateral and vertical distance from the terrain in an area where an unmarked hay transport cable spanned the valley.
- Collision with hay cable: At about 18:45, near 1000 m MSL and roughly 2 km south of Sächseln, the left outer wing struck the Dienenchlawen–Hell hay transport cable, severely damaging the wing skin and structure.
- Loss of roll control: The substantial damage to the left outer wing reduced lift asymmetrically, causing the glider to roll and tip over the left wing into an uncontrolled descending turn from low height.
- Crash - fatal: From a height of roughly 100 m above ground, the pilot was unable to recover or bail out and the glider impacted steep, rocky terrain in the Steckenmattgraben, destroying the aircraft and fatally injuring the pilot.