Mid-air collision between two sailplanes near Lüneburg

Overview and flight details On 21 July 2019, two sailplanes collided while flying in thermal lift near Sonderlandeplatz Lüneburg. The aircraft involved were an Alexander Schleicher ASW 15 and a Burkhart Grob Astir CS. The ASW 15 departed at 11:52:02 local time, and the Astir CS departed at 12:06:10. Both pilots had planned cross-country flights of about 450 km but were not flying as a team. The collision occurred at 12:24:36 at 1,097 m AGL, about 2,100 m northwest of the airfield. ## Pilot accounts The ASW 15 pilot reported receiving a FLARM collision warning showing another aircraft 380 m behind him. He turned right toward a cloud and then saw the other aircraft on his right. After impact, the canopy separated, and the aircraft entered a dive that he recovered from. He landed the heavily damaged sailplane at the airfield. He stated he was not wearing a parachute. The Astir CS pilot said he had seen the other sailplane on FLARM in the same thermal. While centering the next thermal, he saw the other aircraft on his left. His aircraft was in a slight right turn when the collision occurred. He experienced a vertical, partly inverted fall, activated the canopy jettison, unbuckled, and deployed his parachute. After 1 to 2 minutes of descent, the parachute tore and entered rotation. He struck a wheat field and was seriously injured. The uncontrolled Astir CS crashed into a residential area and was destroyed. ## Aircraft and data The ASW 15 was a 1971 private sailplane with 2,938 flight hours, equipped with an LX Navigation Flarm Red Box. The Astir CS was a 1976 club-operated sailplane with 1,472 flight hours, equipped with an LX Navigation Flarm Mini Box. Both had valid airworthiness documentation and last inspections on 2 March 2019. Flight data showed the aircraft on nearly crossing headings in straight flight for the final 18 seconds. The ASW 15 course changed from 281° to 295°, and its ground speed decreased from 67 to 55 km/h. The Astir CS course changed from 228° to 214°, and its ground speed increased from 70 to 81 km/h. The angle between their flight paths was 81° just before impact. ## Damage and parachute The ASW 15 landed on the southern side strip of runway 07/25 with its gear retracted. Its canopy was missing, the nose was destroyed, the fuselage was broken below the seat, and both wings had leading-edge damage. The Astir CS struck the ground in a residential area in an inverted attitude. Its tail was separated, and the fuselage and wings were broken in multiple places. The pilot landed in a wheat field several hundred meters from the wreckage. The BFU could not determine which parts of the two aircraft first made contact.