What happened
On June 11, 2007, at 15:17 UTC, a Ryanair Boeing 737-800, registration EI-CSI, was performing a scheduled flight from London Stansted to Brno-Tuřany. While being vectored for an ILS approach to runway 28 at flight level 61, the flight crew observed a glider performing a steep right-hand turn in close proximity to their aircraft. The pilot in command (PIC) noted that the glider passed the aircraft with a separation of approximately 150 feet at nearly the same flight level.
The crew immediately reported the "glider activity" to Brno Approach (APP EC). The air traffic controller (ATCO) responded that they had no information regarding glider operations in the area. Following the encounter, the Boeing 737-800 landed safely at Brno-Tuřany. Subsequent radar analysis and communications confirmed the presence of a LAK 17 glider, registration OK-1507, in the vicinity.
The investigation
The ÚZPLN investigation examined radar records from the Brno ATS station, radio communications, and pilot statements. Analysis of primary radar tracks confirmed that the glider had entered the TMA Brno airspace near Račice at approximately 15:13 UTC without establishing radio contact or obtaining flight clearance.
The investigation also reviewed the controller's radar display. The ATCO was managing multiple primary targets and, due to the lack of an SSR (Secondary Surveillance Radar) transponder on the LAK 17, the glider was difficult to distinguish from other stationary targets. The investigation noted that the glider pilot later contacted Brno Approach at 15:35 UTC to request entry into the TMA, at which point the pilot claimed to have seen the Boeing aircraft south of his position, outside the Tuřany CTR.
Findings
- The primary cause of the incident was the unauthorized entry of the glider into controlled airspace without communication or clearance.
- The glider pilot entered the TMA Brno without establishing contact with ATC, leading to the loss of separation.
- The lack of an SSR transponder on the LAK 17 made it difficult for the ATCO to identify the glider as a moving target among other primary radar returns.
- The Ryanair crew acted correctly by identifying the conflict and notifying ATC immediately.
- The weather conditions (CAVOK) were suitable for flight.