What happened
On June 7, 2015, an Airbus A321 was operating a commercial flight from Berlin Schonefeld (EDDB) to Hurghada (HEGN). While climbing through FL150 toward a planned FL270, the aircraft was granted an unrestricted climb to FL330 by the ACC GAT sector "D" controller.
At approximately 11:41:15, the aircraft's planned route, which passed through the EP TSA 07 airspace, was displayed on the air traffic controller's radar screen. At 11:44:40, a yellow "ZN" warning alert appeared on the radar display. Approximately 35 seconds later, the controller instructed the crew to execute a 20-degree left turn. The crew acknowledged the instruction to turn to heading 060 degrees and requested the reason for the maneuver.
At 11:46:55, a red "ZN" alert was triggered on the radar, indicating that the Airbus A321 had officially infringed the boundary of the EP TSA 07 airspace. The warning alert disappeared at 11:48:00, and by 11:48:50, the aircraft had descended through FL250 and was cleared to proceed direct to the KELEL waypoint.
The investigation
The investigation, conducted by the Polish Air Navigation Services Agency, established that the EP TSA 07 airspace was active up to FL245 at the time of the incident. The investigation reviewed the controller's credentials, noting that the controller was fully licensed, medically fit, and had completed refresher training in April 2015. The investigation also noted that the controller was working their first shift following a three-day break.
Radar data confirmed that the aircraft's planned flight path through the restricted area was visible on the controller's display. Furthermore, the aircraft's vertical rate of climb remained steady at approximately 1,000 ft/min during the period in question.
Findings
- The controller issued an unrestricted climb clearance despite the aircraft's trajectory intersecting restricted airspace.
- There was a delayed response to the radar warning alerts, as the instruction to turn was issued approximately 40 seconds after the initial yellow warning appeared.