Ok guys, please be gentle with a 742 driver about to embark on a 744 course...
Fuel question: if you depart with less than about 53T of fuel, my operator mandates a tank to engine departure, which on the 744 appears to be OVRDS 2 & 3 off, crossfeeds 1 & 4 closed and 2 & 3 open (as per FMSC logic).
My understanding, however, is that the FMSCs always close crossfeeds 2 & 3 automatically on selecting F10 or F20 after start, and do not open them again until cleaning up to F5 or less. If the FMSCs also do this in the tank to engine takeoff scenario, who is pressurizing the fuel manifold for takeoff? And does it matter?
What have I missed?
MD