French investigators have detailed a serious airprox incident in which an EgyptAir Airbus A300-600 freighter climbed through its assigned altitude.

The aircraft (SU-GAY) had been operating from Ostend to Cairo on 1 January this year, and had been cleared to climb to 21,000ft.

French investigation authority BEA, citing counterparts in Belgium, state that the freighter was re-cleared to this altitude at 11:42 and that its crew read back the clearance correctly.

It was then instructed, 3min later, to maintain 21,000ft once reaching this level and its crew was informed that another aircraft was crossing from right to left above. This clearance was also correctly read back.

The crossing traffic, an Air France Airbus A320 (F-GKXN), had been travelling at 22,000ft while en route from Paris Charles de Gaulle to Amsterdam Schiphol.

BEA says the A320 crew was advised about the climbing EgyptAir flight.

But the EgyptAir crew informed that they were responding to a traffic-collision resolution advisory as the A300 approached 21,000ft, and the aircraft was “observed climbing through the cleared level”, says BEA.

The aircraft “continued climbing”, it adds, although the collision-avoidance system was advising the crew to level.

Collision-avoidance alerts were triggered on both aircraft, with the A320 crew being ordered to climb.

BEA says the separation between the two jets was just 0.74nm horizontally and 300ft vertically. The airprox occurred in the vicinity of Ghent.

Source: Cirium Dashboard