The French Bureau d’Enquêtes et d’Analyses pour la sécurité dans l’aviation civile (BEA) issued its report on a serious incident to the Embraer ERJ170 registered F-HBXK operated by Hop! and to the Airbus A320 registered OO-SNE operated by Brussels Airlines on 21/10/2020 at Paris – Charles de Gaulle: Windshear warning on final approach, flight path deviation during the missed approach, abnormal proximity with an aeroplane taking off from a parallel runway, TCAS resolution advisory
The landing and take-off operations at Paris-Charles de Gaulle airport were taking place on the south parallel runways, in particular weather conditions, with a strong crosswind and moderate to severe turbulence below 1,500 ft.
The ERJ170 was at 500 ft on short final on runway 26L when the crew of the A320 were cleared to take off from runway 26R.
At a height of 200 ft, a Windshear warning was triggered on board the ERJ170. The crew applied the procedure associated with this warning by interrupting the approach and keeping the wings level.
After eight seconds, when the ERJ170 flew through 580 ft in climb, the Windshear warning stopped. The crew identified the end of the windshear situation when the aeroplane flew through 1,000 ft, 11 s after the end of the warning. The crew continued complying with the procedure by keeping the wings level for a further eight seconds up to an altitude of 1,500 ft, in accordance with the operator’s operational instructions for the ERJ170 (refer to paragraph 2.3.3 note 5). They then notified the controller of the windshear and the go-around.
Due to compliance with the Windshear procedure and the strong crosswind, the ERJ170 deviated northwards and closed in on the A320 taking off from runway 26R.
The controller attempted to resolve the conflict by using the emergency phraseology to order the ERJ170 to turn onto a heading of 240°, around 10 s after the ERJ170 had reported the go-around. The crew read back the instruction but the controller’s order to change the heading was not followed. In fact, complying with the TCAS procedure, the crew stopped the turn as they passed through a heading of 250° which resulted in a track of 263°. The crew of the ERJ170 did not immediately inform the controller of the TCAS resolution advisory due to the frequency being busy.
The controller then asked the crew of the A320 to stop climbing without using the emergency phraseology. The latter replied that they were following a resolution advisory emitted by their TCAS.
The crew of the ERJ170 then ambiguously informed the controller that they had also had a TCAS resolution advisory.
The crews followed the orders of the resolution advisory provided by their respective TCAS systems. The minimum separation reached during the incident was 0.09 NM and 460 ft.
Neither of the crews informed the controller of the end of their respective TCAS resolution advisories using the standard message set out in the phraseology rules. The use of the past tense in the non-standard message made by the crew of the ERJ170 stating that they had also had a TCAS may have led the controller to believe that the resolution advisory had ended. The controller therefore issued orders to the crews despite the ongoing resolution advisories.
Note: The Hop! E170 was arriving from Brest and the Brussels Airlines A320 was taking off to Brussels.