Collision between an ultralight aircraft and a glider at Großrückerswalde

Overview and outcome On 10 September 2016, an ultralight aircraft and a glider collided while on final approach to the traffic airfield at Großrückerswalde. The ultralight aircraft was a Flight Design CT SW; the glider was an Alexander Schleicher ASK 21. The two occupants of the ultralight aircraft were killed. The two occupants of the glider were uninjured, and the glider was lightly damaged. The ultralight aircraft was destroyed, and minor ground damage was reported. ## Aircraft and personnel The CT SW was a two-seat, high-wing ultralight aircraft in composite construction, built in 2006, with a Rotax 912 engine and a Magnum Light Speed SP rescue system. It was privately owned by its 54-year-old pilot, who held an ultralight aircraft licence and had about 600 hours of ultralight experience. The ASK 21 was a two-seat glider in composite construction, built in 1993, and was owned by a club. Its 63-year-old pilot held a glider licence, an aerobatic rating, and had about 1,354 hours on gliders and motor gliders, including 153 hours of aerobatic experience on the type. ## Sequence of events An aviation event was being held at the airfield. The ultralight aircraft took off at 12:03 local time for a long circuit flight that was not part of the demonstrations. The glider took off at 13:54 local time for a guest aerobatic flight, towed to about 1,200 m AGL and then climbed in thermals to about 1,600 m AGL while waiting for a parachute drop to finish. The aerobatic display was conducted in a box north of the runway and ended at about 350 m AGL. The glider pilot then flew inverted to the circuit position and reported by radio that the programme was finished. The ultralight pilot reported by radio south of the airfield before entering the opposite side of the circuit. The flight controller said he saw the aircraft there. The glider pilot said he heard radio traffic but was concentrating on the aerobatics. He then made a final approach in a slight side-slip with the left wing forward. ## Collision and aftermath The glider pilot reported hearing a bang to his right and the glider being displaced to the left. He saw the ultralight aircraft’s tail strike the trailing edge of the glider’s right wing near the aileron and the ultralight fuselage pitch up. He attempted to steer carefully, found the controls working, and landed the glider. Both glider occupants were uninjured. The ultralight aircraft crashed into a forest adjoining the airfield at about 14:30 local time and was destroyed. Both occupants were killed. ## Evidence and data Both aircraft were equipped with GPS devices. The glider’s device was not switched on and contained no data for the flight. The ultralight’s GPS data showed the flight path from the 12:03 takeoff, including a route via Annaberg-Buchholz, Oberwiesenthal, south of Bayreuth, and Ebermannstadt, before returning north of Bayreuth over the Fichtelgebirge and Vogtland to Großrückerswalde. At 14:27 the aircraft reached the area south of the airfield after a 2:24 flight. It flew about 2 km straight toward 297°, then made a wide right turn into the final approach to runway 11. At 14:29, about 1.7 km from the threshold, it began its final approach from about 186 m AGL. The last recorded point at 14:29:55 showed an altitude of 46 m AGL and a position about 200 m from the threshold. Witness video and photographs showed the glider coming from the north in inverted flight, rolling to normal flight before the third turn, then making a short crosswind approach and beginning the final approach. The ultralight aircraft was seen below the glider in straight flight. After the final approach turn, the glider entered a side-slip with the left wing down. The ultralight aircraft then turned right. A photograph taken just before impact showed the ultralight aircraft below the glider, with its vertical tail about to touch the right wing trailing edge. Another side-view photograph showed the ultralight aircraft nearly vertical in the air after impact. It then pitched forward rapidly and fell almost vertically to the ground. The glider also changed direction briefly but continued its approach. ## Airfield and weather Großrückerswalde traffic airfield (EDAG) has a grass runway about 1,000 m long and 40 m wide, oriented 110°/290°. At the time of the accident, runway 110° was in use. The airfield elevation is 2,198 ft AMSL. Weather at the time was visual flight conditions with light cloud. The wind was very light and from varying directions. The ground temperature was 27 °C and the pressure was 1,016 hPa.