PZL Bielsko SZD-12A collision with hay transport cable near Sächseln, Switzerland
On July 11, 1965, a PZL Bielsko SZD-12A collided with a hay transport cable near Sächseln, Switzerland. The incident occurred during a ridge flight when the glider struck the cable approximately two kilometers south of Sächseln. The pilot was fatally injured, and the aircraft was destroyed upon impact. The official investigation concluded that the collision was due to the pilot flying into an obstacle-prone area without recognizing the cable in time.
- 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.