What happened
On September 11, 2006, a Boeing 737-800 was operating an IFR scheduled flight from London to Friedrichshafen, carrying 99 passengers and six crew members. Simultaneously, a Panavia Tornado was conducting a training flight under VFR rules, having departed from Ingolstadt. The military aircraft was flying a course of 300° at a ground speed of approximately 360 knots, passing northeast of the Friedrichshafen control zone.
At 10:28:20, Friedrichshafen approach controllers alerted the 737 crew to an aircraft approaching rapidly from their front right. While the crew could see the intruder on their TCAS display, they could not establish visual contact. Shortly after, the 737 was cleared to turn right for the final approach at 240 knots. During this maneuver, the Tornado approached from the left front. The 737's TCAS issued a series of commands, including CLIMB, MONITOR VERTICAL SPEED, and DESCENT, which the pilot followed.
The pilot of the Tornado reported that they had been looking to the left to scan for departing aircraft from Friedrichshafen. Upon returning their gaze forward, the pilot spotted the 737 in a right-hand turn and immediately initiated an evasive maneuver involving a steep right turn and a climb. At 10:29:00, the two aircraft passed each other head-on at an altitude of 4,300 ft. Radar data confirmed a minimum separation of only 0.7 NM with a vertical separation of 200 ft.
No injuries were reported, and neither aircraft sustained damage.
The investigation
The BFU examined the flight data recorder from the 737 and radar records from the air traffic control system. The investigation also reviewed radio communications and the pilot's flight experience. The investigation noted that while the 737 was in contact with Friedrichshafen approach, the Tornado crew was not in communication with any air traffic control service at the time of the encounter.