Originally Posted by
A and C
In a word NO using cabin air pressure does not mean pressurising the whole fuel system to cabin pressure. Quite clearly the system would apply a regulated pressure to the fuel and stop the flow when the fuel tank is empty.
The vent/ surge system does vent the whole fuel system and maintain the whole fuel system above ambient pressure to help gravity feeding of fuel should the boost pumps fail, so in the very worst situation of unregulated cabin pressure getting into the centre tank this air would be vented overboard via the vent/ surge system.
Isn't the center tank inside the pressure vessel?
If so you indeed need full cabin pressure to get fuel into the center tank or the center tank needs to withstand the cabin pressure and it is directly vented to the outside.
anyway i see the problem now.
you said in your post moving fuel INTO the center tank.
but that's not what you meant i guess.