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), an airspace activated for military training involving L-159 aircraft.
At approximately 12:55 UTC, radar controllers identified the aircraft within the active TSA at 3,000 ft AMSL. 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 immediate warnings regarding the conflicting military traffic. The pilot of the Z 526 only became aware of the airspace violation after contacting the Přerov approach controller later in the flight, who informed 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 and the aircraft was airworthy, the crew was communicating on a frequency used for the glider tow rather than with the local approach services. Furthermore, it was noted that the internet connection at the Hranice airfield was unavailable at the time, which had been a primary method for pilots to check for recent NOTAM updates.
Findings
- The pilot of OK-EHO failed to obtain critical information regarding changes to airspace restrictions during pre-flight planning.
- The pilot was unaware that the TSA Troubelice had been activated via NOTAM.
- The aircraft was not in radio contact with any ATS unit at the time of the airspace infringement.
- The pilot did not identify the activation of the TSA during pre-flight preparation.
- Air traffic controllers were unable to provide timely collision avoidance advice or warn military pilots of the intruding civilian aircraft because the crew was not on the appropriate frequency.