Discus CS overtakes paraglider on ridge; mid-air collision

Two pilots were fatally injured when a Discus CS and an Advance Sigma 7 paraglider collided in mid-air near the Galmihornhütte; glider destroyed, paraglider damaged. Weak thermals had concentrated soaring traffic in a narrow area above Münster airfield. After working figure-eights on the slope, the glider overtook the paraglider on its left at ~3× its speed, then turned right back across its path. The right wing struck the paraglider lines at ~140 m AGL. The glider yawed into a spinning descent; the partially collapsed paraglider settled with its pilot likely unconscious. Probable cause: overtaking turn with loss of visual contact.

1. Ridge soaring, dense traffic: The glider pilot launched by aerotow from RWY 05 at Münster and released at ~2 780 m MSL near the Risihorn. Returning to the Galmihornhütte ridge ~2 km NW of the airfield, he flew figure-eights at ~2 400 m MSL on the slope without gaining altitude for about 54 minutes. Weak thermal conditions had kept most local soaring within a short radius of the airfield; at the time of the collision around 18 other aircraft were within 10 minutes of the glider, with 10 of them within ~250 m vertically.
2. Mixed glider + paraglider area: Weak thermals had concentrated gliders and paragliders into the same small ridge area. A published exception to the 5 km hang-glider exclusion zone allowed paragliders to transit the airfield area in summer. The pre-flight briefing did not cover paraglider mixing, as an unusual concentration was not anticipated after the championship the previous week.
3. Paraglider climbs to glider level: The paraglider, having launched earlier from the Fiescheralp and worked thermals along the route, arrived at the Galmihornhütte at ~2 200 m MSL and climbed in a thermal for three minutes, gaining ~135 m. It then continued straight north-east, slightly above the glider, which was still working figure-eights on the slope.
4. Overtake on left at ~3× speed: The glider passed the paraglider on its left, with the slope to its own left, on a heading ~20° less than the paraglider's and at roughly three times the paraglider's speed. The traffic rules prohibit a slope-soaring glider from overtaking another aircraft at approximately the same altitude on the ridge.
5. Right turn back across path: Immediately after overtaking, the glider began a right turn — away from the slope and toward the paraglider's position — most likely to start another figure-eight. The glider pilot had probably already lost visual contact with the paraglider before initiating the turn; with the slope on his left, the low height above terrain and the paraglider on his right, there was no remaining evasive room.
6. Wing strikes lines; glider spins: The right wing of the glider contacted the paraglider's lines, leaving blue-green, yellow-green and red friction marks on the leading edge. The one-sided drag yawed the glider into a rotation around its vertical axis, similar to a spin. The collision occurred at ~140 m AGL, which left no margin to recover into level flight away from the slope; the aft centre of gravity made the recovery more demanding still.
7. Both pilots fatally injured: The glider impacted the slope in a near-horizontal, rotating attitude and was destroyed; the pilot was killed on impact. The paraglider, partly collapsed into a heart shape, descended with its unconscious pilot at a survivable rate; he came to rest head-down on a steep slope and died of positional asphyxia before rescuers could reach him. Two rescue helicopters arrived 23 and 30 minutes after the collision.