What happened
On June 21, 2005, a Fokker 100, registration EI-DBR, operating as Union Jet flight EUJ 203, entered Czech airspace (FIR LKAA) from German airspace (FIR EDUU) without establishing radio contact or activating the required SSR 7600 code. The aircraft was flying from Manston, UK, to Prague/Ruzyně.
Simultaneously, a NATO training exercise was underway. Following the loss of communication with EUJ 203, the Combined Air Operation Center (CAOC) ordered a pair of German Air Force F-4F Phantom fighters to scramble and intercept the non-communicating aircraft.
During the interception, the situation became highly complex for air traffic controllers. One of the intercepting fighters failed to switch off its SSR Mode C as instructed by the GCI controller when approaching the civilian aircraft. This failure likely triggered a TCAS Resolution Advisory (RA) on board the Fokker 100, causing the crew to climb from FL 350 to FL 361. The crew eventually established contact with the Prague ACC sector at the LOMKI waypoint and visually identified the intercepting fighters. The interception was concluded, and the fighters returned to their base in Germany.
The investigation
The ÚZPLN investigation examined radar records, radio communications, and the actions of both the flight crew and air traffic controllers. The investigation focused on the coordination between military and civil authorities, specifically the communication between the Command Reporting Center (CRC), the Military Air Traffic Control (MACC), and the Prague Area Control Center (ACC).
Findings
- The crew of EI-DBR failed to establish radio contact upon entering FIR EDUU and subsequently FIR LKAA, and did not implement any established loss-of-communication procedures.
- The intercepting F-4F Phantom crew did not follow interception procedures, as one aircraft failed to deactivate its SSR Mode C at the requested 20 NM distance.
- The failure of the CRC to immediately relay the interception order to the MACC prevented timely coordination between military and civil air traffic services.
- The GCI provided inaccurate information regarding the activity of the intercepting fighters to the MACC.
- The high volume of traffic and the complexity of the simultaneous NATO exercise placed the Prague ACC controllers under extreme operational pressure, leading to a temporary ban on westward departures from Prague/Ruzyně to maintain safety.