French investigators have highlighted the part played by language differences during a serious conflict incident in which a landing Hop Bombardier CRJ700 was cleared to cross a runway while an EasyJet Airbus A319 was taking off.

The A319 had been cleared, in English, to take off from Lyon’s runway 35L but the air traffic controller, in French, subsequently cleared the arriving CRJ700 – simultaneously landing on the parallel 35R – to cross 35L via the B4 exit.

Investigation authority BEA states that the controller, during his shift, had been routinely clearing landing aircraft to cross 35L, owing to low departure activity on the parallel runway, and that the repetition of tasks had become “somewhat automatic”.

BEA says he issued the CRJ700 clearance “without detecting the conflict”, not noticing the departing A319 during an external visual scan. It adds that the flight-strip processes in place could mask potential conflicts.

But the inquiry also suggests the language difference increased the risk of an accident. The EasyJet crew, it says, “did not understand” the crossing clearance, in French, given to the Hop crew.

“Use of multiple languages in communications with crews can decrease situational awareness of the crews of surrounding traffic,” it states in its conclusions over the 17 March 2017 event.

The Hop crew was based in Lyon and already aware of the possibility of runway incursion, and the pilots checked runway 35L before the crossing. Another visual scan, at the same time, resulted in the controller’s noticing the conflict.

BEA says the Hop aircraft subsequently stopped at a holding point before entering the runway.