Questions tagged [air-conditioning]

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Do aircraft depressurise when taking off from a high elevation airport? [duplicate]

A jet aircraft generally maintains a cabin pressure of 7000-8000 ft during cruise. If the aircraft departs from a high elevation airfield, such as Quito (approx. 10,000ft), will the aircraft ...
user38116's user avatar
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How does air passing through the secondary heat exchanger in an aircraft's AC pack get cooled if ram air is not available/insufficient? [duplicate]

For example, if the aircraft is on ground and bleed air for the AC pack is provided by the APU. Most explanations I've seen say that the air passing through the secondary heat exchanger in between the ...
aokfreak's user avatar
2 votes
2 answers
249 views

What is the difference between a reverse and non-reverse bootstrap ACM?

I'm doing a project for my school about aviation and I ran into reverse bootstrap air cycle machines (ACMs). What is the difference between reverse and non-reverse bootstrap ACMs? Also, which ...
zdeněk choleva's user avatar
3 votes
2 answers
477 views

Why air pressure is raised twice in air cycle machines?

Currently studying about aircraft air cycle machines for my midterm, and this question still kinda stuck in me. So in air cycle machine, in my understanding, the air pressure is raised twice. But I ...
Luthfi Ahmad's user avatar
6 votes
4 answers
2k views

Why is it that some planes require the AC to be turned off during engine start and take off?

I've noticed that some pilots turn off the climate control for start up and takeoff, like the Sr22. Why is this? And has this been phased out with new technology?
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what will happens if there is a leak in air conditioning system? [closed]

In different system such as "Air cycle" and "vapor cycle" air conditioning system.
Ebin Joseph's user avatar
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2 answers
1k views

How are cabin pressure and oxygen level maintained inside the airplane? [duplicate]

How are cabin pressure and oxygen level maintained inside the airplane?
Student787's user avatar
2 votes
2 answers
540 views

HEPA filters, airliner HVAC and COVID 19

There is this report that says the risk of aerosol spreading on a commercial liner is low due to HEPA filters. But it is not considering the cases when A/C is OFF. This seems to be quite common when ...
Andrew Walsh's user avatar
4 votes
1 answer
385 views

How often is the cabin air replaced in A320?

One of the A320 pilots told me that there is an icao rule that air should be replaced every 90 seconds? Is this true ? can someone give me a supporting article for the same
Sourabh Jain's user avatar
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1 answer
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What are the amber triangles on the ECAM bleed page on an A320?

In FCOM they say that triangle becomes amber when RAM AIR flap is not fully open, and both pack flow control valves are closed. Here the RAM air flap is emergency ram air or RAM Air flap for the Packs?...
Sourabh Jain's user avatar
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1 answer
160 views

What does pneumatic operated and electrically controlled means? [duplicate]

I was going through A 320 FCOM and didn't understand this term
Sourabh Jain's user avatar
11 votes
3 answers
5k views

Why is the airflow in airline cabins downwards?

Air is distributed from overhead outlets and flows downwards towards the floor. Since the exhaled air is hotter than the air around, and tends to concentrate towards the ceiling, wouldn't it make more ...
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What powers the air-conditioning on commercial planes?

How is the air conditioning system on airliners powered? I expect that the air conditioning is powered by the APU powers, but I wonder if there are other power sources used like the main engines?
blacksmith37's user avatar
5 votes
1 answer
4k views

Why is ram air not used for air conditioning in airplanes?

If the ram air is used for air conditioning, the airplane doesn't need a heat exchanger, cooling fan and cool the bleed air from compressor. So why do modern planes use bleed air cooled by ram air? My ...
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1 answer
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Do small business jets have HEPA filters?

Do small business jets (Phenom 300 for example) have HEPA filters for recirculated air? Or don't they recirculate air at all?
Pedro Guimarães's user avatar
4 votes
2 answers
2k views

What does the phrase "electrically controlled and pneumatically operated" mean?

While studying the air-conditioning of the A320 from the FCOM I came across the information that the pack flow valves are "electrically controlled and pneumatically operated". I can not understand ...
Anik Bhowmick's user avatar
2 votes
0 answers
45 views

In aircraft air conditioning systems what are the differences between the air cycle machine system and the displacement blower type system?

I have seen reference to both these different air conditioning systems but can't understand what the key differences are and where each system would likely be found.. I.e is one system preferable over ...
Jono 's user avatar
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38 votes
4 answers
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Why is the air inside airliners so dry (low humidity)?

The air inside an airliner is very dry which causes all sorts of passenger discomfort such as dry eyes, dry skin and in some cases headaches. Why is the air so dry and what do or can modern designs ...
Brilsmurfffje's user avatar
6 votes
1 answer
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What's inside the packs? (Airbus a320)

I have some questions about ATA 21, how packs works?... I mean, what's inside them?, what are their mechanims? And How the warm air becomes into cold air?. (On a airbus A320) I'm starting my major at ...
Allan Sanchez's user avatar
6 votes
1 answer
592 views

Is the air in aircraft cabin toxic?

I just listened to the recent BBC podcast episode Aerotoxicity: the hidden dangers of flying and there were interesting claims there: Cabin air in modern passenger aircrafts comes directly from ...
Hask S.'s user avatar
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2 votes
2 answers
205 views

Which are the advantages of low pressure levels during flight? (i.e during cruise flight in a commercial aircraft)

I understand that due to health and security reasons, there must be a minimum in the pressure inside the cabin (75 kPa). But in class I have been told that maintaining low pressure levels has ...
JoseDo's user avatar
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2 answers
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Do pilots get more fresh air than passengers? [duplicate]

There is a famous air travel myth claiming that "pilots get more fresh air than passengers".       (source: The pure cure, p.375) I would like experts to either dispel or confirm this myth, that ...
summerrain's user avatar
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4 votes
2 answers
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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 (...
summerrain's user avatar
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1 vote
2 answers
13k 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 ...
summerrain's user avatar
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3 votes
1 answer
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Why and how can a fume event occur?

« A fume event occurs when bleed air used for cabin pressurization and air conditioning in a pressurized aircraft is contaminated by fluids such as engine oil, hydraulic fluid, anti-icing fluid, ...
summerrain's user avatar
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1 vote
1 answer
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Air quality monitoring devices for a320

I looking for the air quality monitoring devices for a320. How do they look, where they located? thank you for the help
Victor Chernobay's user avatar
8 votes
1 answer
3k views

Why do airplanes have complex air conditioning systems?

I'm wondering why do planes have complex air conditioning systems with several coolers, compressors and turbines. If these devices are powered by bleed air from the engines, why isn't the bleed air ...
Oskari Räsänen's user avatar
5 votes
1 answer
1k views

How common and dangerous are fume events?

I’ve been hearing about fume events where engine oil containing tricresyl phosphate as an additive can leak onto the HVAC packs and enter cabin air. These organophosphate are incredibly toxic and are ...
pythonhelpthrow's user avatar
5 votes
2 answers
7k views

What dictates the A320's 'emergency ram air inlet' operation?

Why does the emergency ram air inlet flap open when delta p is greater than or equal to 1 psi on the A320? Below is the extract I was reading from the FCOM. Why has the figure of 1 psi been set for ...
Jai's user avatar
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3 votes
1 answer
2k views

Why doesn't the A320 pack flow indicate HI as it should?

When on ground with APU bleed on and both engines off I have noticed a number of times that the pack flow isn't at the HIGH setting why? As per the FCOM it states that when APU bleed is on the PACK ...
Jai's user avatar
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41 votes
3 answers
40k views

Do jet fighters have air conditioning systems?

In most jet fighters, the cockpit is a glass dome and the pilots are exposed directly to the sun. In addition, they are wearing flight suits and full face helmets (most of the time). I can only ...
Burhan Khalid's user avatar