What happened
On 23 February 2018, a serious incident occurred within the Brussels Terminal Control Area (TMA) involving two commercial aircraft. An Embraer ERJ195 operated by Air Europa Express and an Airbus A320-214 operated by Deutsche Lufthansa were climbing through approximately FL 70 when they were placed on converging courses by air traffic control.
The conflict began when the trainee air traffic controller (ATCO) instructed the A320-214 to turn earlier than the published route intended, without properly accounting for the flight path of the preceding Embraer ERJ195. As the aircraft converged, the Short Term Conflict Alert (STCA) was triggered on the radar display. The situation escalated quickly, leading to both aircraft receiving TCAS Resolution Advisories (RA). The Embraer ERJ195 received a 'LEVEL OFF' command, while the A32 .214 received a 'CLIMB' command followed by a 'LEVEL OFF'. At the closest point of approach, the aircraft were separated by only 400 feet vertically and 1.36 NM horizontally.
The investigation
The AAIU(Be) investigation focused on the actions of the Brussels Departure station, which was being manned by a trainee ATCO under the supervision of an On-the-Job Training Instructor (OJTi). The investigation examined radar data, crew reports, and the training status of the personnel involved.
Investigators found that the trainee was under significant stress, viewing each shift as an examination, and was experiencing fatigue due to poor sleep. Furthermore, the investigation noted that the instructor did not have a dedicated radar screen, making it difficult to monitor the trainee's work effectively, especially as the trainee's voice was noted to be low and difficult to comprehend.
Findings
- The primary cause was the trainee ATCO's decision to instruct the A320-214 to turn earlier than the published route without considering the projected path of the Embraer ERJ195.
- The trainee's situational awareness was compromised by stress and fatigue.
- The instructor's ability to monitor the sector was limited by the lack of a separate radar display and the trainee's low vocal volume.
- The design of the departure procedures for the involved aircraft naturally led to converging flight paths.
- The flight crew of the A320-214 exhibited a slight delay in reacting to the TCAS RA, though they maintained visual contact with the other aircraft.
Safety action
Following the incident, the Belgian air traffic service provider, Skeyes, modified the sectorization of the approach control area. This change ensures that up to three trainees and their instructors can operate simultaneously with dedicated displays for each instructor to improve monitoring capabilities.