A33Zab;
Yours is a valuable contribution to this aspect of the discussion. My thanks to you for clarifying the THS system and correcting, for other readers, my mistaken impression of the THS operation. I had read the electric-motor component as "the slower" of the two driving systems, ostensibly due to the lower demands of the AFS and, in manual flight, the sidestick. I've gone back to what I have and re-read with your contribution in mind.
Chris Scott;
From the auto-trim point of view, the movement from 3NU to 13NU (after FL375) was very nearly continuous?
I've watched the A340s and A330s THS wheel on the pedestal move slowly in response to small stick movements and changes in airspeed. One can see the movement out of the corner of one's eye because of the paint but I always valued the aural confirmation of movement on those airplanes that had manual trim.
The THS response to sidestick orders is immediate, in other words. I believe then, that as the sidestick was held in the NU command position, (orders still gee-referenced but with rate/gain limits), the THS would follow through, likely at a varying rate in relation to slightly changing sidestick orders. I think once the AoA was below that which the autotrim ceases to function, it would respond to sidestick ND orders. As stated, it would certainly have responded to manual trim wheel input.
A good, (and needed) discussion on "NU" and "ND", thanks. That's exactly the way the "minus 4" symbol for the THS position on the FLT CTRL ECAM page was explained to us when learning the A320 in 1992. Minus meant "tail down, nose up", and I think made good sense once one understood.
On the "roll to the right" upon disconnection, I have to re-iterate that the fuel system for the A340 and A330 were next to flawless in maintaining cross-wing balance of fuel. And there is nothing in the BEA Note to point to cause but any fuel imbalance on this airplane is real cause for close observation. I can't see rudder trim being an issue because it is automatic as well. One doesn't "disconnect the airplane, trim, then reconnect" as one did with the DC8/B727, etc and at that point certainly, it isn't reasonable to consider that asymmetric thrust was a factor.