French Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA) deems “inadequate phraseology” as the culprit of a near-miss incident at Paris Charles de Gaulle airport back in 2014. At the time, two passenger planes ‒ Bulgaria Air’s A319 and Freebird Airlines’ A320 ‒ came dangerously close to each other on an intersecting runway.  

On November 25, 2014, Bulgaria Air’s A319, registered LZ-FBB, has just arrived to Paris from Sofia (Bulgaria), while an A320, belonging to Turkish charter airline Freebird Airlines, registered TC-FBJ, was getting ready to take off on a flight to Istanbul (Turkey). 

To reach their terminal, Bulgaria Air had to cross the 08L runway, used for take offs. The A319 entered the intersection at 08:20:17, after the crew were given instruction “Bulgaria 4 3 1, number one, keep on taxiing”.

At the same time as Bulgaria Air plane entered the intersection, approximately 1,500 m away Freebird Airlines was performing the take-off run at an indicated airspeed of 139 kt. An airport system, which monitors ground movements, detected the conflict and sounded a warning, but “controllers considered that it was then too late to intervene,” the report states

Twenty second later, Freebird Airlines passed the intersection at a height of around 500 ft. The A320 aircraft flew over Bulgaria Air A319 at a height of around 100 ft, Freebird Airlines captain later estimated. The report states that as A320 was passing the intersection, A319 had already crossed it and was stopped on a taxiway. Bulgaria Air crew did not see Freebird Airlines A320, as noted in the report.

The situation was not helped by the fact that a third airplane, belonging to Air France, was taxiing behind Bulgaria Air, on the left. Air France crew, well familiar with the airport, knew that controllers here usually “explicitly” give crossing clearances. After hearing “Bulgaria 4 3 1, number one, keep on taxiing”, they asked whether they were cleared to cross the runway ‒ LOC controller said no. However, this conversation was little help to Bulgaria Air, as it was carried out in French. 

Thus, BEA deems that because ATC “inadequately” communicated taxiing priorities and a reminder to hold short of runway 08L did not accompany the message, Bulgaria Air crew “erroneously” interpreted the message as a clearance to cross the runway. 

The incident happened during a period of dense inbound traffic when aircraft were arriving with a reduced separation.