APU fuel burn with apu bleed ON and both packs OFF

[Electron]

Hi all

I’m trying to find the reference that says that whilst on the ground, leaving apu bleed on with packs off causes 40% unnecessary fuel burn. Can anyone remember where it is?

I could’ve sworn it was in a service letter

[motortek]

737-SL-49-060

[Electron]

Not quite brother. I appreciate the attempt to help though

There is or WAS written SOMEWHERE, that there is specifically 40% loss of efficiency with packs off and apu bleed on, on gnd without eng’s running.

With my boeingfleet changes, i don’t know how to search for historical inactive stuff

[motortek]