A320 / G102 airprox — glider transponder inactive in Class E

An Airbus A320 on IFR approach to Memmingen (Germany) and a Grob G102 on a student training flight came within 0.247 NM laterally and 100-150 m vertically in Class E airspace; both aircraft landed safely. The G102 was thermalling without an active transponder, invisible to ATC and the A320's ACAS. The student saw an approaching landing light, completed his turn, departed at right angles to the A320, dove and accelerated. The A320 crew acquired the glider at about 1,310 m MSL, disengaged the autopilot and briefly pitched up. The inactive transponder left see-and-avoid as the only defence.

1. Training thermalling: A student pilot in a Grob G102 was conducting a training flight, circling left in lift in the Bad Wörishofen gliding area under VFR.
2. No transponder use: The G102 was flown without an active transponder, making it invisible to ATC radar displays used for IFR separation and to the A320’s ACAS.
3. IFR jet approaches: An IFR Airbus A320 on radar vectors for the ILS to Memmingen descended through about 4 300 ft AMSL into the vicinity of the thermalling G102 in Class E airspace.
4. Glider evasive turn: After spotting an approaching light and recognizing the A320 slightly above and converging, the glider pilot completed his turn, then turned northeast and descended for separation.
5. A320 climb maneuver: Upon visually acquiring the glider at about 4,300 ft, the A320 crew disconnected the autopilot for a brief manual climb, overflying the glider within seconds without lateral maneuvering.
6. Safe landing: The two aircraft passed with a minimum radar-measured separation of 0.247 NM and roughly 100–150 m vertically, and both continued their flights and landed safely without damage or injury.