Background
On 27 September 2019, at 10:04 UTC, an Airbus A320, registration EC-MKO, operated by Vueling as flight VLG19ZN from London-Gatwick (United Kingdom) to Barcelona-El Prat, and an Embraer 145, registration F-HRAM, operated by Aero4M on a ferry flight from Castres Mazamet (France) to Barcelona-El Prat, were involved in a loss of separation incident 17.4 NM northeast of Barcelona-El Prat Airport at flight level FL070. The A320 carried 6 crew and 185 passengers, all uninjured; the Embraer carried 3 crew, all uninjured.
Incident Sequence
Both aircraft were under instrument flight rules and in contact with Barcelona ACC. The A320 was communicating with the F25W sector, and the Embraer with the T1W sector. Both were proceeding in descent to waypoint BL443. The A320 overflew BL443 and continued on the transition route. The Embraer was cleared by the T1W controller to proceed direct to waypoint BL435, a shortcut that caused both aircraft to converge at a similar altitude near BL435. Onboard TCAS systems issued Resolution Advisories, prompting evasive maneuvers from both crews. Radar data recorded a minimum separation of 0.8 NM horizontally and 200 ft vertically at FL070.
Aftermath
After the incident, both aircraft continued their flights to Barcelona-El Prat and landed without further event. No damage to either aircraft or injuries to occupants were reported.
Investigation
The Spanish Civil Aviation Accident and Incident Investigation Commission (CIAIAC) investigated the incident. The investigation found that the loss of separation was caused by incorrect planning and execution of the approach sequence by the controller of the T1W sector. No safety recommendations were issued.
Probable Cause
The probable cause, as stated by the investigation, was an incorrect planning and execution of the approach sequence by the controller of sector T1W.