The AC fuel system is there primarily to transfer fuel to the engine(s) yet maintain the balance of the ac. The typical engine fuel pressure may be around 3000-3500 psi however, the ac systems are often low pressure 40-50 psi therefore ac pipes are high bore low weight aluminium and ecu pipework is high strength stainless steel. Nevertheless the ac system must cope with rapid changes in flow requirements, in and out of reheat, as well as extremely rapid changes of attitude and g loading. To that end your backing or booster pumps will supply far in excess of your max requirement and be returned to tank, sometimes via a cooling matrix to remove some heat from elsewhere in the engine, oil or fuel immediately before being burnt.
Accumulators were superseded by DE booster pumps. However if they fail, providing there is fuel being transferred into the collector tanks most Engine Driven Fuel Pumps will drag the fuel out. Fuel is usually transferred from other groups by dc electrical pumps submersed in the fuel. Fuel tanks are now almost exclusively integral and sealed whereas they were previously bag tanks. Most fuel managment/transfer is carried out automatically to maintain trim and balance.
One additional thing not often found on large aircraft, Fat Albert being the one exception I am aware of is the use of external fuel tanks. Usually the fuel is transferred up once there is sufficient space inside the fuselage, this can be either by pressurising the tank using engine bleed air and the pressure forces the fuel through a stack pipe or using dc pumps again. All other things; filters, pressure raising valves, non return valves, and low and high level sensing devices will be common.
All dead easy really.
Slopjockey