If the Prims & Secs get the wrong information the flight controls will become un-useable due to their envelope protection functions. You have to get down to direct law to restore order, which will allow the pilot to set attitude & power.
to achieve direct law you need to disconnect 2 Prims and one Sec, if I recall correct. This by means of a Bulletin published by AB. Furthermore this has to be done on the overhead panel.
Now just imagine you find yourself in a sudden upset in a complete unusual attitude with erroneous instrument indications. - Good luck in even finding that panel, notwithstanding being able to push the correct pushbuttons in due time...
- this is quite frightening! Are you guys seriously telling us that there is no quick, easy button press to allow back side-stick to raise the elevator and you have to go groping around on the overhead pushing buttons?