Cat. 2 investigation report: simplified-format report, adapted to the circumstances of the occurrence and the investigation stakes.
Established on ILS 25 at Paris-Orly, the copilot-PF disconnected the autopilot (AP) at 1,400 ft with a view to landing. Four seconds later, and without any forewarning, the crew were surprised by the predictive windshear warning, “GO AROUND, WINDSHEAR AHEAD” (Phase 1). The captain ordered a go-around which was flown in manual flight control by the copilot. This led to an immediate and brutal break in the crew’s action plan, substantially increased their workload and considerably changed the rate of work after a flight of more than 11 hours. The flight phase suddenly became very dynamic, all of the occurrence sequence lasting around four minutes and the difference in altitude between the start of the go-around and the stabilization altitude at 2,000 ft being small.
The captain-PM’s call for a go-around in immediate response to the predictive windshear warning may have contributed to the destabilization of the copilot-PF. The copilot thought that the AP was engaged whereas this was no longer the case, and made no input on the sidestick after the initiation of the go-around. The plane started to deviate from the missed approach path and the FD command bars progressively moved off-centre on the two axes. The copilot, confronted with the surprise effect in connection with the unexpected triggering of the predictive windshear warning, the change in the rate of work and the increased workload was then “absent” for a few minutes. This cognitive incapacitation was not initially identified by the captain or the relief pilot.
In the vertical profile, the go-around was continued to around 800 ft above the stabilization altitude, and this despite the position of the FD command bars, the altitude alerts and the altitude calls made by the captain-PM and relief pilot. Although the captain had quickly identified this flight path deviation, he took over control of the aircraft and started correcting the flight path more than 50 s after busting 2,000 ft.
In the horizontal profile, it was the slight right input on the copilot’s sidestick on increasing the nose-up attitude at the beginning of the go-around and not subsequently corrected, and the FD command bar indications not being followed, which resulted in the plane being around 650 m to the right of the runway centreline, and flying over the control tower.
The copilot then put the aeroplane into level flight at an altitude of around 2,800 ft. The captain had just put his hand on the sidestick when the copilot probably extended the speedbrakes without calling this out. After calling out “I have control”, the captain engaged the AP (Phase 2) to return to the published missed approach path by turning left and descending to 2,000 ft. The case of the PM taking late control of the flight path once the aeroplane configuration changes had been completed, is typical of the occurrences in the study carried out by the BEA into Aeroplane State Awareness During Go-Around (ASAGA).
In the dynamic context of the go-around, the cognitive incapacitation of the copilot was not verbalized by the crew. The captain had to manage a high workload on his own: flight control and navigation as well as handing radio communications and the conflict with a plane taking off from runway 24.
The extension of the speedbrakes, very probably commanded by the copilot, led to an increase in the VLS and the activation of the low energy alert “SPEED, SPEED, SPEED”. For the captain, this was the third disruptive element at the end of this flight, coming after the predictive windshear warning and the copilot’s incapacitation. The captain then returned to conventional manual flight control with the objective of increasing speed and then stabilizing at 2,000 ft. He temporarily put the thrust levers in the TOGA detent (which automatically caused the speedbrakes to retract) and disengaged the AP by his actions on the sidestick (which also disengaged the FDs due to the effect of a mode reversion). He continued the descent while monitoring the separation with the other aeroplane. In this very emotional situation, the stability of his manual flight control was affected.
During this descent and in reaction to a suggestion made by the relief pilot, the copilot engaged AP2 without coordinating this action with the captain. The latter was surprised and did not understand why the AP was engaged in V/S mode. This led to his firm request for silence in the cockpit, “Everybody silent, I’m the only one giving orders” to allow him to concentrate on the management of the flight. He then disengaged AP2 to engage AP1.
After a descent to 1,550 ft, the captain stabilized the plane at 3,000 ft as requested by air traffic control (Phase 3). As the copilot felt better, he became PM for the landing which took place without further incident.
Final Report (EN)