Originally Posted by
BuzzBox
On the NEO aircraft, the X BLEED is left in AUTO, the APU may be left running, but the APU bleed is selected OFF as above.
I’ve always found funny that APU Bleed OFF is specifically written in the manuals in both my last and current operator FCOM yet in the FCTM it is explained that running the APU bleed with engines running(for example if you’re planning to use it to supply packs for Take Off) is more efficient than keeping the APU running while using engine bleed. And at least the second operator has modified the FCTM green operating procedure section to mention that removing the 250kt limitation bellow 10.000ft AAL is not allowed, so if they didn’t want us to use APU bleed during taxi they could have modified that section of the FCTM as well.
On a semi unrelated note, I am not sure if running the APU bleed when running single engine is more fuel efficient than keeping the APU on and using engine bleed, or if running both packs out of the APU bleed is better for cooling than a single pack out of the engine bleed.