Incident Overview
On July 18, 2018, a mid-air collision occurred between a Reims Aviation Cessna 172 N and an Alexander Schleicher ASW 20 glider. The incident took place approximately 2,000 meters northwest of the Sonderlandeplatz Borken-Hoxfeld (EDLY), over agricultural and forestry terrain. Both aircraft sustained significant damage but remained airworthy, enabling the pilots to fly back to their respective departure locations.
Flight Operations and Sequence of Events
At approximately 18:10 local time, the Cessna 172 N was in cruise flight heading southwest at an altitude of roughly 420 meters above ground level. The aircraft had departed from Flugplatz Stadtlohn about 15 kilometers to the north, carrying three passengers. Simultaneously, the ASW 20 glider, which had started its journey from Borken-Hoxfeld after a seven-hour cross-country flight, was executing turns northwest of the airfield to lose altitude for landing.
According to the Cessna pilot and a passenger, the glider was visible in their field of view for at least one minute. The Cessna pilot initially corrected his course to the right to increase separation while discussing the glider with passengers. He reported that the glider suddenly changed its turn direction, appearing larger and closer than expected. Despite an immediate evasive maneuver to the right, a collision occurred.
The glider pilot stated he was turning northwest to descend. Upon noticing the approaching motor aircraft during a change in turn direction, he initiated a steep turn. The impact happened approximately two seconds later. Radar data and GPS logs from the glider corroborated these accounts, confirming that the glider had completed two full right-hand turns before switching to a left-hand turn about four seconds prior to the collision.
Aircraft Damage and Condition
The ASW 20 suffered severe damage to its right wing, where a section of approximately 1.5 meters was severed and not recovered. The remaining portion of the right wing exhibited delamination and leading-edge splits. The left wing and fuselage remained visually intact. The Cessna 172 N sustained damage to the lower third of its left strut, which was bent near the footstep area. Green paint transfers and composite material debris were found on the strut, indicating contact with the glider's wing.
Environmental and Operational Context
Weather conditions at Borken-Hoxfeld were favorable, with visibility exceeding 10 kilometers, winds from the northeast at 4–6 knots, a temperature of 25°C, and a QNH of 1,017 hPa. Both aircraft were operating under Visual Flight Rules (VFR) in Class E airspace. No radio communication was established between the two aircraft or with air traffic control.
The Cessna 172 N, registered in the Netherlands and held by a German flight school, was equipped with a Mode-S transponder but lacked a collision avoidance system. The ASW 20, privately owned in Germany, was fitted with a FLARM (Flight Alert and Radar Map) device. Both pilots held valid licenses and medical certificates at the time of the incident.