Preliminary data based on the notification from the United Kingdom authorities:
On 4 June 2016 at 15:19 UTC in the controlled airspace of the Republic of Bulgaria, sector 'Sofia-West', it was admitted a violation of the minimum standards for the safe separation between aircraft transiting the upper airspace of Bulgaria. Airbus A320-232 aircraft, reg. marks TC-ATK, of 'Atlasjet' performing flight No KKK5LP and Boeing 737-8F2 aircraft, reg. marks TC-JGF of 'Turkish Airlines', flight No THY7FX, passed each other with minimal horizontal distance of 2,6 nm and 500 ft. vertical separation. Due to the approach admitted, the automated collision avoidance systems (ACAS) on board of both aircrafts reacted. Both pilots in command reported “TCAS RA”.