A320 engine start

[Citation2]

Is it possible to keep one pack on during engine start ?

FCOM says : "Engine start sequence : If the crossbleed valve is closed , the valve located on the Starting engine side immediately closes when the Mode selector is set to IGN

It remains closed on the starting engine side ( provided the crossbleed valve is closed)"

Then further down there is a note : "If the crossbleed valve is open at engine start, both pack flow control valves close."

Crossbleed valves automatically opens with APU bleed ON . Does that mean that If the crossbleed valve is manually shut prior to engine start , only the associated pack will close ?

But then the question , can you start engines with Xbleed closed ?

[Beeline]

With your crossbleed closed with the plumbing you would only be able to start the left engine from the apu, BMC will cmd left pack valve to close on start.

No air would be on the right pack valve so it will be shut anyway. Pneumatically operated, electrically controlled.

The aircraft will not allow MES with ECS, not enough flow from apu, risk of abnormal start.

[DutchOne]

It might be possible if you start engines with the apu ---> you start ENG 2 first (not what airbus recommends) ---> close the crossbleed (as apu bleed has priority) ---> cycle the start selector, (now only ENG1 pack valve and bleed valve are closed) ---> start ENG 1 with APU, provide pack 2 with ENG 2

But why would you?

[Citation2]

Thanks for your inputs . I was just wondering whether it is possible because the FCOM notes say: If the Xbleed valve is closed the valve located on the starting engine side immediately closes " . So I don t understand why they are stating this case , if its not considered feasible or would give an abnormal start .

Then FCOM says : "If the crossbleed valve is open at engine start, both pack flow control valves close."

SO they are considering 2 cases : One where You would start with Xbleed closed which would result in the closure of only the associated pack .

Second case : Xbleed Open , and close both packs during start .

They put the accent on the Xbleed valve position during start, which give 2 different results . Please Refer to FCOM 1 Air Conditioning System , Packs

[capt. solipsist]

So I don t understand why they are stating this case , if its not considered feasible or would give an abnormal start .

Gallic logic

[Last Ditch]

Frankly, I see nothing wrong with the statements.
Its just making sure that the bleed air is provided only for engine crank during start.
Unless.... I am not seeing something you all are!!

[Ripudaman Thakur]

Came here after reading "Air Conditioning during Automatic Engine Start" in my FCOM and this is what it exactly states lol

[pineteam]

After engine 2 start, you close the Xbleed. Doing so allowed the engine 2 to provide bleed to Pack 2. Then proceed to start engine 1. After both engines are available you reset the Xbleed to Auto position.
This is a supplementary procedure you can find in the FCOM for the A320 neo aircraft as due to the cooling time being quite lengthy, the cabin might get very hot. This procedure is doable on the CEOs even tho you won’t find the procedure in the FCOM as the engines are quick enough to start without affecting the passengers comfort.

EDIT: Just realised it was an very old threat.