Mid-air collision between ASK 21 and DG-600 near Schupfart results in two fatalities

On June 4, 2001, a mid-air collision occurred between an Alexander Schleicher ASK 21 and a DG Flugzeugbau DG 600-18 near Fricktal Schupfart Flugplatz, Switzerland. The ASK 21, carrying two pilots, collided with the DG 600-18 during flight, resulting in the destruction of both aircraft. The collision led to the tragic fatalities of both pilots in the ASK 21, while the pilot of the DG 600-18 survived with injuries after deploying his parachute. The accident was attributed to the pilots not seeing each other in time to avoid the collision.

1. Aerotow — local soaring: The DG-600 launched by aerotow from Schupfart at 11:48 and, after release southeast of the field, turned left and flew straight toward an area with several circling gliders near cloudbase.
2. Congested thermal area: Around the time of the DG-600’s release there were already several gliders operating near a low cloudbase of about 1100–1200 m MSL south of the airfield, concentrating traffic in a relatively small area.
3. Limited visual acquisition: Weak, broken thermals, possible cloud fragments, and the difficulty of seeing white gliders against a bright background reduced the likelihood of early visual detection between the DG-600 and the ASK 21.
4. Gliders converge unseen: Approximately 40 seconds after release, the ASK 21 approached from the DG-600’s right rear and slightly below, and neither crew detected the conflict in time to initiate an avoiding maneuver.
5. Mid-air collision: The DG-600, flying essentially straight, struck the left side of the ASK 21’s tail with its right wing, the ASK 21’s tailplane then impacting the forward fuselage of the DG-600 and severely damaging both aircraft at about 1150 m MSL.
6. DG-600 pilot bailout: After feeling the collision and loss of canopy, the DG-600 pilot released his harness, exited the aircraft, deployed his parachute, and steered to land in a field instead of the nearby forest.
7. Crash - fatal: The unmanned DG-600 descended into trees and the ASK 21, likely in a steep, possibly inverted attitude without elevator control, crashed into the forest with both pilots fatally injured while the DG-600 pilot survived with serious leg injuries.