Boxkite Montgolfier AMF
I am struggling a little with your concept.
If the Ap disconnect was inadvertent, would the pilots not re-engage immedietly to preserve protection integrity?
Boxkite,
Among other ways, most autopilots will disengage themselves if the aircraft begins rolling or pitching due to outside forces to outside pre-defined limit built into the autopilot itself.
The same is true if it's set to hold a particular altitude but outside forces or decaying airspeed/high AOA approaching a stall exceeds the autopilot's ability to maintain that altitude. Therefore, it's set to disengage by design, accompanied by a warning to the pilots that essentially tells them "you're flying the airplane now".
It should also be mentioned that most
generic procedures for inadvertent CB penetration call for de-selecting the Altitude Hold function of the Autopilot even if it remains engaged to allow variations in altitude occur due to extreme updrafts and downdrafts. This is so the AP doesn't keep running pitch control/trim servos to max limits in the futile attempt of trying to maintain a selected altitude which could result in overstress and/or far out-of-trim situations. Perhaps someone here could post what the A330 QRH/AFM procedure calls for with regard to Alt Hold if encountering a CB/Severe Turb?
These limits are designed into autopilots so it doesn't try and overstress the aircraft or keep trying to fly it when the wing stops flying, so through engineering they limit how far it can respond with control surface deflections. In the closed thread, others have posted what those particular pitch, roll, etc. limits are for the Airbus 330-200 aircraft. In severe or extreme turbulence, it's very possible the aircraft was pitching or rolling up to, and beyond, one or more of these internal trip points.
And an autopilot will lock-out engagement (or re-engagement) if you're handflying flying outside of these built-in parameters. So if violent pitching or rolling was/is occuring, you can select engagement as many times as you want but it won't because it needs to see all the parameters met for its engagement first.
Hope that clears up your question, and explains my line of thinking as to why it's the big, red flag of this event.