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Old 22nd May 2015, 18:06
  #191 (permalink)  
KenV
 
Join Date: Aug 2014
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In common with most large aircraft, by design the A400M fuel system keeps as much fuel as far outboard as possible all the time for wing bending moment relief. As fuel is used from the feed tanks, they are topped up from the centre and transfer tanks in that order. (There is a slight modification to this in a tactical fuel loading mode which I won't describe here - but that's not important right now.)
Most? I can't speak for "most", but that's not how Douglas did things. Consistent with Douglas' conservative design approach, C-17 does not operate that way. There are four wing tanks on the C-17. And they feed fuel to their associated engines equally. The outer tanks are not kept full for wing bending relief. On those C-17s with a center tank, the center tank transfers fuel to the four main tanks equally until the centertank is dry. The center tank is filled last and emptied first, and cannot be used to feed the engines, but it transfers fuel to the wing tanks equally.

Last edited by KenV; 22nd May 2015 at 18:28.
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