It was explained to me by a very experienced training captain and fleet manager that there is a subtlely of the Flight Controls Architecture diagram in the QRH that is not readily appreciated, (or taught):
Each controlling ELAC or SEC only operates one hydraulic jack in each flight control surface - the one shown above the ELAC/SEC number. So for example, the left aileron is normally controlled by ELAC 1 operating the Blue hydraulic jack. If ELAC 1 fails, ELAC 2 takes over operation of the left aileron, but it does so by operating the Green hydraulic jack - not the Blue - i.e. each ELAC or SEC is hard wired to only one specific jack in each location.
To explain another example; the right elevator is normally controlled by ELAC 2 operating the Yellow hydraulic jack. If ELAC 2, or Yellow hydraulics fail, then the right elevator will be controlled by ELAC 1 operating the Blue hydraulic jack.
With this knowledge, the diagram becomes even more useful and informative when working out the results of computer or hydraulic failure scenarios.
PS, I think there is a mistake in my electronic FCOM in the schematic at the bottom of DSC 27-10-20 showing the SERVOLOOP PRIORITIES table for the elevators; in that they have not drawn the control line from the right elevator Yellow jack all the way to ELAC 1, so it looks as if ELAC 2 might control the Blue and Yellow right elevator jacks, but I don't think it actually does.
Last edited by Uplinker; 17th Apr 2016 at 09:09.