"No, no....nowt to do with the 'dunnies'."
Understood, CJ.... Just a feeble attempt at humour <img src="wink.gif" border="0">
The schematics (for our RR-powered aircraft) show the Right FCU inputting into the HYDIM to start up the #1 ADP when the flaps are in transit....and the Left FCU inputting into the HYDIM (different circuit board) to start up the #4 ADP with the flaps in transit.
Most CF6-powered aircraft seem to have the additional logic to run the ADP's when the flaps are also "out of up".
As you say, it's interesting to note that a particular FCU controls a particular ADP. Normally, if a particular FCU fails to perform its duties another will take over. If that fails, the third FCU will take over (but if the FCU's are hardwired to the ADP controls, then this is of concern).
Cheers.
Q.