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Questions tagged [bleed-air]

Bleed air is hot air taken from the compressor stage of turbine engines, used to power other aircraft systems.

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3answers
6k views

Why is bleed air taken from some stage of the compressor used for de-icing? Why not e.g. exhaust gas?

In the answers to this question, it is said that The de-icing system on most turbine aircraft (including MD-82 involved in that accident) uses bleed air from the engines, that is it extracts some ...
2
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2answers
595 views

Do pilots breathe the same air as passengers?

Do pilots breathe the same quality of air as passengers ? (i.e. identical parameters: same O2, CO2 and O3 levels, same temperature, same humidity, etc.) Do pilots breath the same air as passengers (...
6
votes
1answer
3k views

Why can't we use APU bleed air for wing anti ice on the A320?

The question says it all. While reading I came across this that we can under no circumstances use APU bleed air for supplying wing anti ice? Any reason?
10
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4answers
2k views

What kind of filters are being used to filter the bleed air?

Bleed air is using by airplanes for various purposes including deicing and also to feed air conditioning units that maintain temperature inside cabin. What kind of filters does bleed air pass through ...
9
votes
3answers
3k views

Is the bleed air passengers breathe tapped from the engines before or after it comes in contact with fuel? And why? Isn't this unhealthy?

Passengers are often surprised to hear that the air they breathe comes from inside the engines. This sounds unhealthy. Can you explain, why it is not ? Is bleed air tapped (for cabin pressurization) ...
1
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2answers
2k views

Why does the cabin air sometimes smell of kerosene? [duplicate]

Why does the cabin air sometimes smell of jet fuel, although bleed air is tapped before it comes in contact with fuel ? How is this possible? I have smelled this a couple of times in my life (twice ...
12
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2answers
2k views

How much thrust is lost due to the bleed air system?

I've read that bleeding air for the pneumatic system from the engine core can produce important losses in thrust, and also rising the fuel consumption too. Today this problem is worse, with the more ...
3
votes
1answer
606 views

What is the function of this small hole on the B737's hydraulic reservoir line?

This is picture of a B737-800. When you open the bleed system a small amount of air is discharged from this hole (marked with an arrow, lower right). What is it for? And what happens if this hole gets ...
3
votes
2answers
557 views

How much is air mass flow rate of bleed air used for environmental control system in civil aircraft?

I'm looking for a general use-case formula or reference that I can use to calculate the total mass flow rate of bleed air use in the environmental control system of any aircraft. I'm not looking for ...