Thank you all for your inputs
You must stay within the CG envelope for landing. Fuel in center tank may have a serious effect on CG.
Thanks for highlighting.
MEL ops procedures do not apply when airborne.
That’s correct, MEL is applicable on ground. But there is nothing that stops from referring to the MEL in air. You might want to change your destination in order to avoid a NO-GO situation on ground when MEL is finally applied (at a place where there is no maintenance).
Return to base, not worth the hassell, you may have a serious electrical problem which may furthur develop
I’ll count that in dollars not cents as it is rare that both pumps would fail simultaneously. There must be something else behind it.
The manual states directly that as soon as the wing tanks are less than full, you may not be carrying more than 1000 lbs (454 kgs) of fuel in the center tank. So, as soon as you START to use wing tank fuel with more than 1000 lbs (454 kgs) of center tank fuel, you're outside the ZFW limitation.
I don’t think that you’ll bust your ZFW limit as soon as you start using your wing tank fuel. But you’ll definitely bust it after sometime and that’s what I am trying to find out i.e. its calculation.
But perhaps it’s not possible to calculate that and due to this fact one should land back on the basis of the limitation which you’ve mentioned. However I am not sure if this limitation refers to what we are discussing as the QRH says nothing about busting any structural limits. All it says is that you might not be able to continue to your destination due to unusable fuel.