Originally Posted by
mm43
...but just prior to, the turbulence had created a pitching moment that didn't correlate with the vertical speed. Hence the A/P disconnect.
The UAS was a secondary.
Are you disputing the BEA's findings?
Originally Posted by BEA Interim#3 (English) P73 Para. 1
At 2 h 10 min 05, the sudden drop in the measured airspeeds, likely due to the obstruction of
the Pitot probes by ice crystals, caused autopilot and autothrust disconnection (the thrust was then locked) and the change in the flight control law from normal to alternate. The presence of turbulence, shown by the inputs by the AP to control the roll in the previous seconds, led on disconnection to the airplane beginning a roll to the right of up to about 8°.
According to the BEA, the turbulence was responsible for the roll, but the A/P disconnect was initiated by UAS - this makes sense as moderate turbulence should not be enough to cause A/P disconnect.
@Lyman - The graph comes from BEA Interim#3 page 111 - I just did a screengrab and moved the relevant traces next to each other (vertical movement only - no horizontal) in the same way I and airtren have done before so that the graphic does not take up more vertical space than it needs to. This is basic pixel-pushing of the kind I've been doing since I was 11 years old. You can print that page and draw the line with a ruler and it will tell you the same thing. I've done it again here with the sidestick trace included just so you'll know I'm not fiddling you:
The pitch up and climb was initiated by the PF's sidestick input - whether he manipulated the controls before, simultaneously or after he said "I have control", that stick was halfway back for 2 or 3 seconds before the aircraft started climbing.