Introduction
On 23 February 2018 at 10:35 UTC, a serious incident involving an Embraer ERJ195 (callsign AEA1172) and an Airbus A320-200 (callsign DLH4Y) occurred in the Brussels Terminal Manoeuvring Area (TMA) around Flight Level 70. The event was classified as an airprox. Both aircraft were operating under IFR and were in commercial air transport. No damage or injuries were reported.
History of Flight
Brussels Airport was using Runway 07R for departures and Runway 01 for arrivals. Departures and traffic in the east TMA were controlled by the Brussels Departure station, staffed by a trainee air traffic controller (ATCO) supervised by an on-the-job training instructor (OJTi).
At 10:30:11, a Beechcraft B300 King Air 350 (B350) called on departure frequency after taking off from Antwerp Airport. It was instructed to continue heading and climb to FL150.
At 10:32:15, the ERJ195, following the CIV 7J departure from Runway 07R, called in passing 3700 ft. The ATCO cleared it to FL070. Its climb rate increased to 3000 ft/min. The A320, following the SPI 5J departure, called in at 10:32:42 passing 2700 ft and was cleared to FL080.
At 10:32:57, the ERJ195 was re-cleared to FL080 and advised of opposite traffic at FL90. At 10:33:10, the B350 was routed direct to waypoint REMBA, crossing the extended Runway 07R axis. At 10:33:21, the ERJ195 was instructed to turn right to VOR station CIV. At 10:34:03, the A320 was instructed to turn right to REMBA.
At 10:34:19, the A320 started its right turn, 5 NM laterally from the ERJ195. At 10:34:49, a Short Term Conflict Alert (STCA) appeared on the radar display. The A320 was passing FL69, 4 NM from the ERJ195 at FL67. At 10:35:00, the ATCO instructed the ERJ195 to turn left heading 180 immediately. At 10:35:06, the A320 was told to stop climb immediately. At 10:35:14, the ERJ195 was instructed to descend to level 60, but the crew replied "Unable, TCAS RA." The A320 also reported a TCAS RA at 10:35:26.
The closest point of approach (CPA) occurred around 10:35:27, with 400 ft vertical and 1.36 NM horizontal separation. Separation was lost at 10:35:05. After the conflict, at 10:35:43, the ERJ195 reported clear of conflict. ATC cleared both aircraft to continue climb to FL110.
Crew Reports
The ERJ195 crew reported that during a right turn to CIV, they received an instruction to turn left immediately and descend. They were simultaneously alerted by TCAS with a "TRAFFIC TRAFFIC" and then a "LEVEL OFF" resolution advisory. They disengaged the autopilot and followed the TCAS, obtaining visual contact.
The A320 crew reported clear weather (CAVOK). They received a TCAS RA ("CLIMB" followed by "LEVEL OFF") and followed it, though slightly delayed. The captain noted that shortly before the climb RA, ATC had advised them to stop climb.
Factors
The investigation identified organisational, human, and environmental factors. Organisational factors included availability of ATC procedures and equipment. Human factors involved incorrect action selection, expectation/assumption, situational awareness, and stress of the ATCO, as well as the trainee-instructor coordination. Environmental factors included physical workspace positioning and the effect of departure procedures. Technical factors were not determined.