ASW 19B collision with tree during aerotow at Mollis airfield
On May 12, 1983, an Alexander Schleicher ASW 19B glider collided with a tree during an aerotow launch at Mollis airfield in Switzerland. The glider was being towed by an aircraft in moderate foehn turbulence conditions. Approximately two minutes after takeoff, the right wingtip of the glider struck the top of a fir tree, leading to a crash. The glider was destroyed, and the pilot sustained fatal injuries. The tow aircraft returned safely to the airfield without damage.
- Aerotow takeoff: The ASW 19B glider took off from Mollis on runway 20 at 11:45 under moderate foehn turbulence, in aerotow behind a DR400 towplane.
- Low climb, early turn: After about 300 m of ground roll with good initial climb, the tow pilot turned right toward a sparse stand of trees, contrary to the instructed foehn tow pattern and at only about 20–30 m above ground.
- Flight in turbulence: Moderate foehn turbulence caused variations in tow rope tension and sink over the river and adjacent wooded area, reducing vertical margins above the terrain and trees.
- Airbrakes extended on tow: Witnesses observed the glider’s airbrakes being extended and retracted, or remaining extended, during the low-level tow, causing the glider to fly lower than the towplane.
- Low over tree tops: The tow combination passed over the stand of fir trees with the towplane only about 10 m above the treetops, leaving the lower-flying glider with minimal clearance.
- Wingtip strikes tree: The glider’s right wingtip struck a fir treetop about 24 m above ground, roughly 1 m below the tip, causing the outer wing to kink upward and rearward and rendering the glider uncontrollable.
- Crash - fatal: With the right wing badly damaged and still attached to the towrope until it broke under overload, the glider crashed and was destroyed, fatally injuring the pilot, while the towplane returned safely.