737NG Pack Flow
It's written in the Boeing 737NG Maintenance Manual that, with the packs in AUTO and both engine Bleed Switches OFF, the packs will go to High Flow. The Pack Wiring Schematics are pretty complex, but the logic appears to be valid with or without the APU running or with the aircraft in the air or on the ground.
Is there any operational reason for running the packs in High Flow in this configuration? If you only have the APU (or External Air) to feed the packs, rather than two engines, why would you want to make a single bleed air supplier work so hard? Why would you switch off the Engine Bleed switches anyway?
If you wanted High Flow, why not just select High Flow with the Pack Switches?
Thanks.
Cheers.
Q.