What happened
On July 24, 2016, at 15:47 UTC, a loss of separation occurred between two aircraft operating within the Barcelona UIR. The first aircraft, a Boeing 767-300 with registration EI-CMD, operated by Blue Panorama, was flying from Rome-Fiumicino to Vilo Acuña at flight level 310. The second aircraft, an Airbus A320-232 with registration EC-MGE, operated by Vueling, was climbing from Barcelona to Manchester.
During the climb, the controller authorized the Airbus A320-232 to proceed direct to the MARIO waypoint at flight level 330. As the aircraft climbed, the distance between the two aircraft decreased, resulting in a minimum separation of 1.5 NM horizontally and 200 ft vertically. This proximity triggered Traffic Advisory (TA) and Resolution Advisory (RA) alerts on both aircraft. The crew of the Boeing 767-300 executed a descent, while the crew of the Airbus A320-232 performed a climb in accordance with TCAS instructions. No injuries or aircraft damage were reported.
The investigation
The investigation examined radar data, flight recorder information, and communications between the aircraft and Air Traffic Control (ATC). Investigators found that the executive controller in sector PP2 had authorized the climb to FL330 for the Vueling flight. At the time of the incident, a shift handover was occurring between the executive and planner controllers, which diverted attention to other traffic in the sector.
Radar analysis showed that a conflict alert (PAC) had been activated prior to the loss of separation. However, the executive controller believed the alert involved a different aircraft (VLG3263) and did not take corrective action, choosing instead to silence the alarm. The investigation also noted that the controller' and the planner did not verify the specific aircraft involved in the alert during the handover process.