What happened
On May 9, 2006, a Z 526 aircraft, registration OK-EHO, was performing a flight from Hranice (LKHN) to Žamberk (LKZM) while towing a Glasflügel 304 glider. During the flight, the aircraft entered the Troubelice Temporary Segregated Area (TSA), which had been activated for military training involving L-159 aircraft.
At approximately 12:55 UTC, radar controllers identified the aircraft within the restricted airspace. Because the pilot of OK-EHO was not in communication with the relevant Air Traffic Services (ATS) at the time, controllers were unable to issue an immediate warning regarding the conflict with military traffic. The pilot only became aware of the airspace violation after contacting the Přerov Approach (APP EC) later in the flight, at which point the controller notified the crew that they had flown through the active TSA.
The investigation
The investigation, conducted by a joint commission from ÚZPLN and ŘLP AČR, examined the pilot's pre-flight preparations, the communication logs between the crew and various ATS units, and the availability of NOTAM information. The investigation established that while the pilot was properly qualified, the aircraft was operating on a frequency used for the glider tow rather than a frequency that would allow for direct coordination with the active military airspace controllers. Furthermore, it was noted that the internet was unavailable at the Hranice aerodrome on the day of the flight, which had been a primary source for pilots to check recent NOTAM updates.
Findings
- The pilot failed to obtain critical information during pre-flight planning regarding the activation of the TSA Troubelice.
- The pilot was not in radio contact with any ATS unit while transiting the restricted airspace.
- The pilot did not realize the TSA had been activated via NOTAM due to a lack of updated information during flight planning.
- Air Traffic Services were unable to provide timely instructions to avoid the conflict because the aircraft was not on a monitored frequency.
- The military aircraft involved in the training did not report the presence of the conflicting civilian traffic.