Why can't we use APU bleed for wing anti-icing? A320
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Joined: Aug 2025
Aviation Qualifications: ATPL
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From: Serbia
Why can't we use APU bleed for wing anti-icing? A320
Hello everyone,
Long story short, I've started my TR few weeks ago, and during one of the sessions I've asked my instructor, what's the reason we can't use APU bleed air for wing anti-icing? He was puzzeled by this question and said that he doesn't know to be honest, so he gave me a "homework" till the next session to figure this out. I'm aware that it can be used for wing anti-ice testing for 30s before automatically stoping but that is not the answer hes looking for, the main question is why can't we use it regurally. I've tried looking into the FCOM and AFM but no luck. Could any one of you guys help me out?
Aircraft in question A320
Long story short, I've started my TR few weeks ago, and during one of the sessions I've asked my instructor, what's the reason we can't use APU bleed air for wing anti-icing? He was puzzeled by this question and said that he doesn't know to be honest, so he gave me a "homework" till the next session to figure this out. I'm aware that it can be used for wing anti-ice testing for 30s before automatically stoping but that is not the answer hes looking for, the main question is why can't we use it regurally. I've tried looking into the FCOM and AFM but no luck. Could any one of you guys help me out?
Aircraft in question A320
Joined: Oct 2019
Aviation Qualifications: Non-Aircrew
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From: USA
Would that not require drawing bleed air from the APU and routing that air some possibly considerable distance from the APU to the wings?
If the APU doesn't already supply bleed air, then how would there be any available?
If the APU doesn't already supply bleed air, then how would there be any available?
Joined: Sep 2004
Aviation Qualifications: ATPL(H)
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From: Canada
Would the APU provide sufficient bleed air to deice the entire aircraft?
Another factor may be the space / weight / complexity of the required ducting and wiring.
What would the be probability of needing the capability? ( the dreaded cost / benefit analysis ) .
Another factor may be the space / weight / complexity of the required ducting and wiring.
What would the be probability of needing the capability? ( the dreaded cost / benefit analysis ) .
Joined: Oct 2019
Aviation Qualifications: Non-Aircrew
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From: USA
Only half a speed-brake
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From: Commuting not home
Joined: Mar 2005
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From: England
Nothing to do with bleed temps, just Airbus chose not to certify use of APU bleed for wing anti-ice on the A320 wheres Boeing did (with conditions).
Most of it is to do with continuous output being not sufficent through the flight envelope (from the APU) wheras it is from the engines when serviceable.
That's my understanding.
Most of it is to do with continuous output being not sufficent through the flight envelope (from the APU) wheras it is from the engines when serviceable.
That's my understanding.
Joined: Apr 2004
Posts: 509
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From: United States of Europe
The APU is able to deliver +/- 1.2kg/s bleed flow.
The 2 air conditioning packs need +/- 1 kg/s bleed flow.
The 2 WAI valves need +/- 0.7 kg/s bleed flow.
Therefore, as the APU and the engine cannot deliver together bleed to the aircraft, if the APU is selected for the bleed, the APU is not able to deliver enough bleed flow for the Packs and the Wing Anti-Ice.
The 2 air conditioning packs need +/- 1 kg/s bleed flow.
The 2 WAI valves need +/- 0.7 kg/s bleed flow.
Therefore, as the APU and the engine cannot deliver together bleed to the aircraft, if the APU is selected for the bleed, the APU is not able to deliver enough bleed flow for the Packs and the Wing Anti-Ice.
Joined: May 2026
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From: Montreal
APU bleed vs engine bleeds
On the A320 series, the second the APU bleed is on, both engine PRVs close. It's designed that way.
It is hard to imagine a scenario where you would want your engine bleeds off and be using the APU bleed for wing anti ice.
It is hard to imagine a scenario where you would want your engine bleeds off and be using the APU bleed for wing anti ice.
