If I may join the discussion.
Who here has experience flying the A330 (either simulator or real life) in ALT 2 law? Did you ever practice/experience this configuration with a lateral imbalance? I'm trying to figure out if the AF 447 PF might have had serious problems with controlling the roll axis to such an extent that it interfered with pitch control.
Useful collateral information would be how much force is required to achieve 2/3 lateral stick deflection or full lateral stick deflection. I think you can see where I am going with this.
If you will remember, ALT 2 law operates with the roll channel in Direct law.
I've never been in a Bus's cockpit, so I need some knowledgeable feedback in this area.
Thanks.
Mb
PS Found some data from an old post on A320 stick forces. Wouldn't A330/340 stick forces be comparable?
For A320 from 2004 post by 'Max Angle'
The figures copied from an Airbus publication and converted from horrid Euro units to pounds are:
Breakout force: 1.1 pounds
Pitch: Fore and aft. +/- 16 degrees 22.5 pounds
Roll: Outboard 20 degrees 5.6 pounds.
Roll: Inboard 20 degrees 7.8 pounds.
Note that the force is different for inboard and outboard roll. Airbus found during development that your arm is stronger moving inboard than outboard and fine tuned the forces to make left and right roll feel the same. Try moving the stick left and right holding it from above next time you are at work, you can clearly feel the force difference.
Just ran some experiments using a scale.
With steady lateral force in the 7 pound range using 1 finger, I wouldn't want to do that much more than 30 seconds. Three to 4 fingers can generate this level of force much more comfortably. I'm wondering if the AF 447 PF felt the need to "palm" the stick. That might explain an involuntary climb.
Instead of rotating the wrist, he might have used the wrist 'curling action to move the stick on the roll axis.