Hi MB2002,
Also, there is no possibility of correcting the fuel imbalance.
By flying one wing low and gravity feeding both engines, you'd be able to use the fuel from the higher tank.
"WHEN FUEL IMBALANCE REACHES 1 000 kg (2 200 lb):
BANK ANGLE
2° or 3° WING DOWN ON LIVE ENG SIDE
Use fuel from the opposite wing tank, until fuel imbalance is reduced to 0.
// END"
Edit to Lancer in #4
that section only applies to OEI, but yes you can gravity transfer from one tank to the other
That's the only reference I can find to fuel balancing whilst gravity feeding, but if it works OEI - then it should work with both running.