A320 bleed/eng anti ice

[Jkotows2]

What's stages are the IP and HP tapped off from? Why does airbus want the engine ati ice on on the descent even if it's slow -40 vs in the climb and cruise stages of flight?

Thanks

[Zaphod Beblebrox]

Here is a link from a CFM publication for Lufthansa. It deals only with the CFM engine, not the IAE engine.

Ice and Rain Protection
Engine Anti Ice
A319 / A320 / A321
CFM 56-5A
30-21en

FRA US-E Bu July 1999 Page: Page: 286
ATA 30 ICE AND RAIN PROTECTION
Vacbi File: ENGINE ANTI ICE SYSTEM PRESENTATION
30-20 AIR INTAKE ANTI-ICE PROTECTION
ENGINE AIR INTAKE ANTI-ICE SYSTEM
PRESENTATION
Source
Air is bled from High Pressure Commpressor 5th Stage of each Engine.
Valve
For each Engine, hot bleed air is ducted via an ”ON/OFF” valve.
The valve is pneumatically operated,electrically controlled and spring loaded
closed.
Upon energization of the solenoid, the valve will close.
In case of loss of electrical power supply and pneumatic air supply available,
the valve will open.

It has a “Manual Override and Lock”. It can be blocked in the OPEN or in

https://www.metabunk.org/attachments...ine-pdf.16733/

[lomapaseo]

Could you expand on your question above and clarify it by parts. I suspect there are some misspellings and/or typos that are blocking what you want to ask.

The answer about the stages is complete but I don't understand how that relates to the other or "why" parts of your question

[wiedehopf]

@lomapaseo

i would guess this:
"What stages are the IP and HP tapped off from? Why does airbus want the engine anti-ice on during the descent even if it's below -40 but not in the climb and cruise stages of flight?"

[vilas]

The possibility of icing exists at sustained low RPM as in descent.

[Jkotows2]

But bleed air is modulated and IDLE increseases to allow for sufficient ice protection on descent. So why is there any difference from climb and cruise vs descent?

In regards to the stages I was curious about the CFM and what stages IP and HP are tapped from.

[vilas]

But bleed air is modulated and IDLE increseases to allow for sufficient ice protection on descent

True! But only when you select the anti ice ON.

[Goldenrivett]

So why is there any difference from climb and cruise vs descent?

During the climb & cruise, once OAT <-40 you won't climb into icing conditions.
As you descend the OAT will get warmer so you'll definitely descend into more severe icing conditions sometime soon.

[lomapaseo]

So why is there any difference from climb and cruise vs descent?

Some engines have differences at descent conditions that there is a need to up the fan speed to avoid generating icing on the fan blades and resultant vibration. The concept is that icing sytsems need be automated to some degree to avoid increasing the work load on pilots trying to chase excessive vibration changes in the engine when operating in icing conditions specified within appendix "C"

[wiedehopf]

jkotows2: according to what was posted some posts above ... which you seem to have overlooked ... bleed air is only taken at the HP 5th stage see bolded text in the quote below.

do engines generally have multiple bleed taps?

[Metro man]

If dispatched with the HP valve locked closed (IAE engine), on descent you need to open the cross bleed and select bleed air off on that side to eliminate the risk of high pressure air from the other engine overcoming the low pressure and flowing into the engine. There are valves to prevent this but Airbus think the extra precaution is worthwhile.

Even if the temperature is below the icing range, engine anti ice still needs to be used in the vicinity of CB clouds, the A330 is more susceptible to engine ice in these conditions, as a couple of operators have found out, but the recommendation applies for the A320.

The increase in idle is significant with engine anti ice on and selecting it on the ground may cause the aircraft to move forward. Likewise on descent, keep a careful eye on your profile, particularly if using a high cost index as you will have little margin to increase speed if getting high.