speck wrote on Sep 11^th, 2010 at 6:40pm:

Has anyone been able to start the engines with the main central fuel tank empty?

After seeing your post, I went and tried it. Yes I can. This was how the fuel was distributed in the tanks:

Left Aux     100%
Left              0%
Center          0%
Right            0%
Right Aux    100%
Left Tip      100%
Right Tip    100%

I COULD NOT start the engines if:
(1) only the Left Aux had fuel (100%)
(2) only the Right Aux had fuel (100%)
(3) only the Left Tip had fuel (100%)
(4) only the Right Tip had fuel (100%)

I COULD start the engines if:
(1) only the Left had fuel (1% 272.6 lbs)
(2) only the Right had fuel (1% 272.6 lbs)
(3) only the Center had fuel (0.4% 306 lbs)
(4) if the Left Aux and Right Aux tanks both had fuel (0.9% 140.1 lbs each)
(5) if the Left Tip and Right Tip tanks both had fuel (4.8% 141.2 lbs each)

The fuel Boost Pumps for the tanks that have fuel must be turned ON. NO fuel in tank, NO fuel boost pumps. The fuel Boost Pumps for the Left Aux will also pump the fuel from the Left Tip into the Left Aux first. The same applies for the fuel Boost Pumps for the Right Aux pumping fuel from the Right Tip to the Right Aux first.

Of course any single tank with fuel (excepting the Center Tank) is NOT a good idea. ;D

Mark