737MRG, from what I see, there's no way to get fuel from left side to right side (check valves) or vice versa (so no danger there). There is no way to transfer fuel in flight in the NG, (other than the scavenge pump, from CTR to Left Wing tank) you can only "crossfeed" one engine from the opposite side wing tank. And that also applies to mba's statement about filling the CTR tank from the right side (not possible, other than scavenge pump CTR to Left Wing tank at 177lbs/hr).
In some aircraft (310/330/340 e.g.), there is a "trim" tank in the tail section that has the ability to transfer fuel forward to the CTR tank, but no lateral shifts (in modern era jet transports).
Any Airbus drivers care to supply the info as to whether there is a straight forward "Fuel Leak" checklist that describes both a tank leak and an engine leak?
Or perhaps the risk is so little, that manufacturers don't see the need for a true tank leak c/l?
Note: This Boeing website (
http://www.boeing.com/commercial/aer...y.html#table02) document spells out that casues of a fuel imbalance may include structural leaks, or a tank to tank transfer. I stand corrected on this second point.