Mirage at 700 km/h grazes ASK 23 during military photo survey

An ASK 23 grazed a Mirage in a mid-air over the Solothurn Jura; the glider was substantially damaged but the pilot landed uninjured. After aerotow release at ~1600 m MSL the pilot cruised the Jura corridor and sighted the Mirage three times during its low-level photo survey runs at ~700 km/h. On the third sighting the jet banked 80° left toward the glider; an instinctive pull-up turned the impact into a glancing strike that split the lower fuselage and bent the elevator pushrod. The probable causes: see-and-avoid unworkable at jet closure speeds, and military photo work simultaneous with active soaring in the corridor.

1. Aerotow local flight: The ASK 23B was aerotowed from Grenchen for a local training soaring flight and released at about 1600 m MSL between Grenchenberg and Hasenmatt.
2. Busy soaring area: Multiple gliders were operating in the Solothurn Jura between Chasseral and Weissenstein, a common 'soaring corridor' on such days, increasing traffic density.
3. High-speed Mirage survey: A Mirage RS was conducting infrared photo survey lines at about 1220 m MSL in the same area at roughly 700 km/h with significant bank angles and limited forward visibility from the cockpit.
4. Low glider conspicuity: The modern white ASK 23B presented a very slim frontal silhouette that was difficult to detect visually against the horizon.
5. Mirage turns toward glider: While the glider cruised west toward Grenchenberg, the Mirage, previously seen flying west-east at similar altitude, suddenly turned left toward the glider with a steep bank.
6. Pilot pulls up: Seeing the Mirage rapidly closing with little time to react, the glider pilot instinctively raised the nose in an attempt to avoid collision.
7. Mid-air collision: The two aircraft made glancing contact that split the glider's fuselage underside and bent a control pushrod, but it remained controllable and the pilot landed safely, uninjured.