747-400 question(s)

[Jack57]

Hi there

I was hoping that someone with some 747-400 expertise may be able to help.

I am thrying to find the reason for the "max fuel transfer weight" limitation applicable to the 400.

Why does it exist? (I'm guessing a CofG explanation but not completely sure as to why)

and

Why is there a max speed associated with fuel trapped in the reserve tanks?

and just to make life hard....

Could anyone explain why MTOW reduces with lower specific gravity values?

Any information would be much appreciated.....

Jack

[spannersatcx]

Wing stress/load relief.

sg changes, volume of fuel remains the same but weight changes.