I think what they mean is that fuel is only fed from the main tank, I;d imagine that the Aux's and Xfeed dump into the main tank which then feeds the engine. someone with more knowledge on the a/c is sure to correct me if I'm wrong
kudos to the in depth data on the fuel system...do you mean to say that there is no crossfeeding? most 2 engine planes have a method of feeding the right engine from the left tanks and vice versa.
can anyone blow this up to read the fuel panel