Overtaking ASW 19 strikes a DG-400 from behind while soaring an alpine peak
Two experienced pilots were fatally injured when a DG-400 and an ASW 19 collided in mid-air near the summit of Piz Chalchagn; both gliders destroyed. Both had winch-launched from Samedan for alpine soaring in strong, broken thermals. A witness saw them cross the summit about 100 m overhead, the ASW 19 overtaking the DG-400 from behind, faster and slightly lower; the collision itself was unseen. Trace analysis showed the ASW 19's tail skid struck the top of the DG-400's left wing. The DG-400 lost part of its left wing and dived to the ground, while the ASW 19's fuselage broke ahead of the tail. The probable cause was inadequate lookout.
- Winch launch for alpine soaring: Both pilots winch-launched from Samedan for an alpine soaring flight, the ASW 19 at 11:53 and the DG-400 at 12:33; their tracks until shortly before the collision are unknown.
- Converging over the summit: In strong but broken thermals near Piz Chalchagn, the two closed on each other; shortly before the collision they crossed the summit from SW to NE at about 100 m above the ground.
- ASW 19 overtaking from behind: A witness on the summit saw the ASW 19 clearly faster and slightly lower, closing on the DG-400 from behind.
- Low contrast, lookout hindered: Low contrast against snowfields and nearby cloud may have made the other glider hard to see; whether either pilot saw the other could not be established.
- Tail skid strikes the wing: The collision itself was unseen; forensic trace analysis matched the ASW 19's tail skid to a strike on the top of the DG-400's left wing, after a brusque last-moment change of course.
- Both gliders break up: The DG-400 lost about 2.9 m of its left wing and dived steeply to the ground; the ASW 19's fuselage broke ahead of the tail and it fell at once onto the east slope.
- Crash - both pilots fatal: Both pilots were fatally injured and both gliders destroyed, about 400 m apart on the Piz Chalchagn; neither pilot attempted to bail out.