Skyjob, It is a structural limitation. Just the same as why the main tanks have to be full if centre tank fuel is uplifted (although there is a small amount of centre tank fuel that is allowed to be carried provided that the weight of this fuel when combined with the ZFW does not exceed the Maximum ZFW).... It call all be found in the Fcom
Last edited by Javadreaming; 19th Nov 2013 at 13:48.
Reason: Poor spelling