Serious incident to the Bombardier Challenger 300 registered HB-JGQ and the Schempp Hirth Nimbus 3DM registered D-KPHJ occured on 23/05/2019 near Basel

The pilot of the glider entered the Basel class D TMA 3 and flew within it for around 20 min without making any radio contact or activating his transponder. In a left turn at an altitude of 4,600 ft, the glider’s flight path entered into conflict with that of the Challenger 300 being radar vectored to its destination of Basel-Mulhouse airport. In a descending left turn during the approach, the crew of the aeroplane saw the glider and carried out an evasive manoeuvre. As the glider pilot had not activated his transponder, the aeroplane’s TCAS did not detect the presence of the glider and thus the conflicting flight paths. In addition, in the absence of radio contact, mandatory in Basel TMA 3, the air traffic controllers were not aware that the glider pilot was flying through this airspace and did not ask him to activate his transponder.

As not all of the glider’s flight path data was retrieved, it was not possible to determine and confirm the vertical and horizontal distances between the glider and the aeroplane estimated by the pilots.