A320 apu bleed usage in engine failure
 

Hi to all,

I have a question to you all. in the engine shut down cl we see that if the eng 1 fire p/b is pushed we use apu bleed with xbleed at shut position.
what is the reason that we use apu bleed? What happens if I don´t use apu bleed. Only thing that I can think of is go-around performance.

thanks:hmm:

We don't do it with engine 1 fire bush button pushed. But with No2 Fire button pushed you may do it if required. It's not mandatory.

You do it just to take some pressure off of the good engine in an effort to preserve it, simple as that. It is not required and the engine will function normally but why not try and take care of the good engine.

There is no checklist but ECAM which doesn't even tell you to start the APU leave alone using bleed. One live Engine is capable of all air-conditioning loads and also single bleed two pack operation. The APU is started for electrics so in case the only generator fails you don't land up in ELEC EMER. APU bleed is only used in case of overweight landing to provide better gradient, again not necessary you can just switch off the pack in approach.

Thank you all for the responds

Spin-off from the pneumatics towards air-conditioning.

After engine failure on a packs-off departure: Once MCT is set, do you put both PACK switches on, or only the one for the live engine? As there is no AIB guidance, what is your best practice? Any downside to either of the options available?

For the moment, my choice is to put both PACKs on as early as practicable:
- no need to evaluate stuff
- recovers all the options that might become available or needed later
- come back from the "green" PROC to a configuration that was assumed when ABN PROC and ECAM designers did their work.

I do the same, mainly for the same reasons.

The use of APU Bleed is mentioned in the Engine Shut Down checklist towards the end.

In Airbus we don't have check list we have ECAM which doesn't tell you to start APU. Strictly after ECAM one is supposed to refer FCOM Abnormal procedure which tells you to start APU if available. That means it isn't a priority item.

Ok it’s not mandatory but i asked why does fcom recommends apu bleed

heard of an instance where after and engine failure no damage, smoke started coming out of pax ac outlets, affected pack was deselected.

My $0.02:
If the PACKS had been ON forT/O, the ECAM/FCOM doesn't tell you to turn OFF the affected side PACK does it?

without damage it always tell you if performance permits cross bleed open. This opens the failed pack. So both packs should be put on.

Yeah, that is what I was hinting at...

The A320Neo Eng. Shutdown ABN PROC says to turn off the affected pack... If you can remember of this step, I can't see why not to do so.