A320 Crossbleed OPEN after engine start
 

In the FCOM, it states that after engine 1 start is completed, assuming we would single engine taxi, the crossbleed should be set in the OPEN position to run both packs. In my company, we keep the crossbleed in the AUTO position. I believe that by feeding both packs we save fuel but I have no reference or data to show that. Does anyone know? Thank you in advance.

A320 Crossbleed OPEN after engine start
 

Feeding both packs would rather increase FF, wouldn't it?

I don't think necessarily. You may be right. That's why I am trying to find a reference or some data. With one engine and crossbleed auto, the pack will go to high flow and it may take longer to cool off the cabin. With two packs supplied, I think it may cool off the cabin quicker and reduce slightly fuel flow. I was told that's the case on the 73. Never flown this aircraft so I couldnt say whether it is true or not.

Can it be pax confort?

pack one goes to the flight deck, while pack 2 supplies the cabin (although in single configuration one feeds both, but still the offside gets less air, I believe)

I've seen modulated idle increase considerably with crossbleed open.
There must be savings on single pack.
But on two engines or APU, a recent airbus presentation says the savings are negligeable Or variable on single pack.

Hi MD,

Any references for that ? In my outfit we operate 1 pack on ground with APU running for fuel saving, but I have never seen any figures on how much we do actually save.

Another question regarding reduced engine taxi : when we taxi out single engine we open the crossbleed to feed both packs, but when we taxi in single engine we leave it on AUTO. Logically if it saves fuel/improves comfort running 2 packs then it should be the same during taxi in. Any thoughts ?

Cheers.

Likewise I've always thought that the crossbreed stays in AUTO for single engine taxi in also because it falls in line with the FCOM procedures for running on a single bleed source because of pre-cooler performance unless you select Pack Flow LO.

Why leave it in OPEN for single engine taxi out?

Good point. hopefully somebody can shed some light.

The more bleed demand there is; the more fuel is used, simple as that......

We use one engine and one pack to taxy out. Then no packs for take off.

I've just had an amazing idea....why don't we all charge a sensible fare to the passengers, so that we can run both packs, have our cabins at a comfortable temperature, train our cadets properly, have proper rest, proper recurrent training and decent ground handling, including baggage, etc., etc,.......

The passengers would have good leg room, and good in-flight service, and a decent back-up service if things went wrong.

Sorry about the thread creep, but Just a thought...

What I've seen is...

One pack+1 eng 440kg/h eng + APU burn. Open crossbleed FF then goes 480-500kg/h+APU burn, with a much higher Idle (IAE when both pack selected on)

Mode I like is, 1 eng, 1 pack (other turned off) crossbleed open so the eng start procedure takes 10sec rather than the 30sec when you have to wait for the crossbleed to open (more looking out time!). As you have the second pack off the idle doesn't modulate higher.

Ah you see Uplinker, you want all the same things that the passengers want. Except the fair price of course.