The usual 2 pennies....
Limitations from AFM:
- If more than 453 kg are in the centre tank, wings must be full;
Limitations from Operations Manual Bulletin, Jul 3, 2001:
- For ground operations, center tank fuel pump switches must NOT be positioned to ON unless the center tank fuel quantity exceeds 453 kg, except when defueling or transferring fuel.
- Center tank fuel pump switches must be positioned OFF when both low pressure lights illuminate.
- Center tank fuel pumps must NOT be ON unless personnel are available in the flight deck to monitor low pressure lights.
Within our airline:
- Takeoff with centre tank pumps on, with less than 1000 kg is NOT recommended, to avoid "low pressure" lights and master caution blinking during the T/O roll and initial climb.
So... 11000.. Wings full and some 2000 kg in the centre tank should get the job done!
And yep, Standby HYD pump is powered by GEN 1 (with alternate provision from GEN 2), so AC powered.
Cheers.