Airbus GRVTY FUEL FEEDING procedure and WHEN L(R) TK FUEL REQRD
In case all pumps in an inner tank failed the procedure is to switch them off and open the X FEED. Therefore, there is no need to apply the GRVTY FUEL FEEDING procedure just yet, since the fuel lines are still pressurized. This also gives more time to fly at cruising level and possibly to deaereate the fuel, which in turn increases the GRVTY FEED CEILING.
Now: How long can we prolong this situation? How long can we fly feeding both engines from one tank?
Gravity fuel feeding can only take place from the respective tank, right? (or wrong?!) So if we depleted the tank with good pumps, then not only would we be in need for gravity feeding, we would also have an engine shut down due to fuel starvation.
Also, there is no possibility of correcting the fuel imbalance.
there seems to be no guidelines for that, in the FCOMs nor QRH
Only the line WHEN L(R) TK FUEL REQRD