What happened
On May 14, 2015, at approximately 14:19 local time, a Boeing 737-800 en route from Antalya, Turkey, to Nuremberg, Germany, experienced a serious flight disturbance due to a close approach with an unidentified glider. The aircraft was carrying 113 passengers and six crew members.
While descending through 6,200 ft AMSL in controlled airspace, the flight crew observed an object to the left of their flight path. The pilot in command (PIC) identified the object as a glider performing a right-hand turn, likely in a climb. To prevent a collision, the pilot deactivated the autopilot and initiated an evasive maneuver by adjusting the heading from 300 degrees to 308 degrees and reducing the rate of descent. The glider passed beneath the left wing of the airliner at a distance estimated by the pilot to be between 100 to 150 meters horizontally and 150 to 200 feet vertically. There were no fatalities and no injuries resulting from the encounter.
The investigation
The BFU investigation examined radar data, flight recorder information, and radio communications. The investigation confirmed that the flight crew reported the encounter to Munich Radar immediately after the maneuver. However, the air traffic controller reported that no radar target corresponding to the glider was visible on the controller's display. Flight recorder data corroborated the pilot's actions, documenting the autopilot disconnection and the subsequent heading and descent changes at 14:19:25.
Findings
- The glider was flying without an active transponder, which prevented it from appearing as a secondary radar target.
- Because the glider lacked transponder information, it was also invisible to the collision warning system installed on the Boeing 737-800.
- The glider did not appear as a primary radar target on the air traffic controller's equipment.
- Weather conditions at the time were reported as CAVOK with good visibility, though some light to moderate turbulence was present below the cloud base.