What happened
On August 17, 2008, at 09:21 local time, a serious flight disturbance occurred in the departure area of Frankfurt/Main Airport involving two aircraft. The first aircraft, a BAe 1ob6-300 operating under Instrument Flight Rules (IFR), had departed from runway 07R and was climbing on the BIBOS 7E departure route. The second aircraft, an Ikarus C42 ultralight flying under Visual Flight Rules (VFR), was transiting the area.
Radar data from the air traffic service provider indicated that the two aircraft reached a minimum horizontal separation of only 0.1 NM. The crew of the BAe 146-300 reported a vertical separation of approximately 200 to 300 feet. The captain of the commercial jet observed the ultralight approaching from the left, prompting the first officer to perform a slight leftward course correction to maintain separation. The crew subsequently notified air traffic control, at which point the controller confirmed seeing a primary target on the radar screen.
The investigation
The BFU investigation examined radar recordings from the air traffic service provider and radio communications between the air traffic control center and the BAe 146-300, as well as communications between the flight information service and the Ikarus C42.
The pilot of the Ikarus C42 stated that while flying a VFR route from Gießen-Lützelinden to Bremgarten, he lost his orientation. He realized the error only after checking his position via a GPS device. Approximately ten minutes after the encounter, the ultralight pilot contacted the flight information service and was advised to exit Class C airspace by flying in a 140-degree direction, a directive the pilot followed immediately. The pilot of the Ikarus C42 reported that he did not see the BAe 146-300 during the encounter.