Questions tagged [cabin-pressure]

Airplane cabins are pressurized so that the air inside remains breathable at high altitudes.

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8
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3answers
2k views

Is it possible for a pressure loss in the cockpit to not extend to the cabin?

I have done research into the question of pressure differences between the cabin and cockpit and the theoretical answer I receive the most is that the pressure difference would equalize almost ...
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1answer
151 views

What happens if the crew do not set a FLT ALT in the cabin pressurization panel and leave it at zero but AUTO is still selected?

On the 737NG, will the cabin maintain a lower altitude than the plane or will cabin altitude equal aircraft altitude? Will there be ANY cabin pressurization or none at all? When will the HORN sound? I ...
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3answers
242 views

Was there ever a supersonic flight in a non-pressurized plane, and what is/would it be like for the pilot?

If you went supersonic in a plane that has no pressurized cockpit, would you be completely deaf (because of flying faster-than-sound)? Would it be dangerous to the pilot even if he/she was in an ...
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1answer
171 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
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2answers
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How does outflow valve work?

As we know that outflow valve normally closes during climb and cabin altitude also increase but why does outflow valve open if we have selected manual pressurisation and increasing cabin altitude !
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1answer
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Does ELMS inhibit cabin pressure alarms on the 777, and would the MEC Override Vent be stuck open following an electrical failure?

I found this article rather interesting, but like most things on the internet, they can be wrong. I couldn't think of a better site to address this question. This user says: when ELMS takes over ...
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3answers
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How can I communicate an emergency de-pressurization descent to the cabin as a passenger?

Hypothetical scenario. I'm on a commercial airliner (A320) as a passenger, sitting by the wings. We are cruising at 32,000. The oxygen masks suddenly drop down and the nose pitches down heavily, ...
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0answers
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Why does the 737-300 outflow valve indicator give different readings?

The 737-300 outflow valve opens and closes in manual mode under AC or DC side. While in DC, the indicator is accurate, but when it's in AC mode it reads open when closed. Does the outflow valve have ...
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1answer
457 views

Can Airbus A320 doors be opened mid-flight?

Today I learned how airliner doors are typically an outward facing plug and cabin pressure would make them nearly impossible to open mid-flight. It's easy enough to see that for the shape of Boeing ...
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3answers
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Why does a decompression occur when a hole appears on the fuselage of an aircraft? [closed]

I've never understood the mechanics behind explosive decompression and what is has to do with the difference of pressure. I know the pressure in the cabin is set to a certain point, but don't ...
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How are turboprops and other propeller planes pressurized?

I know how most turbofan jets are pressurized: But it can't be the same with turboprops, as I don't understand how propellers can take in the air. Yet, planes like Q400s can fly above 8000', all the ...
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What is the Function of Pressurization Light on Exit Doors for Commercial Airliners?

I am well aware that the average human is unable to open plug doors in flight due to pressurization of the cabin. I've noticed, however, a "cabin pressure" warning light in the window of exit doors, ...
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1answer
217 views

What is the physical experience of passengers in the cabin during an Emergency Descent?

I am not a pilot so please forgive any misuse of aviation terminology; I'm merely a person who is working hard to overcome a sudden and intense fear of flying. While working through a course to ...
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6answers
683 views

Why don’t airports use jetways as an airlock to avoid having to repressurize the plane for every flight?

Seems like it could save money perhaps. Has this been considered in the past?
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1answer
302 views

How does a DC-10 flight engineer manually raise the cabin altitude?

Reading into Federal Express Flight 1406 and I noticed when the flight engineer said he was raising the cabin altitude “manually” I assume this has something to do with cutting off the oxygen, but how ...
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If you depressurize an aircraft at FL340, will the temperature inside fall to match the temperature outside?

Assuming you’d have an oxygen mask on before hand, and you depressurized the aircraft at FL340, would the inside and outside temperatures quickly become the same?
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Is the F-16 cockpit pressurized?

Is the F-16's cockpit pressurized? If so, why does the pilot receive oxygen from the mask (please state the correct terminology for this)? Is it due to redundancy in case cabin pressurization fails?
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1answer
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What is pressurization influence (if any) on maximum G load an airliner can withstand?

Reading here about skin thickness of airliners I was wondering if, considering some pressurized airliner at cruise altitude, there are differences in maximum operational acceleration loading the ...
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1answer
155 views

Can pressurized aircraft be flown without pressurizing

Are there any pressurized aircraft models which can also be flown without pressurizing the cabin? For example, if there were a short ferry flight, or a flight where the aircraft never got high enough ...
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2answers
119 views

How does cabin pressure vary with respect to ambient pressure during descent?

I came across this statement in a book - "During a descent, the cabin pressure in a pressurized aircraft usually climbs at as lesser rate than ambient pressure". Could someone explain this statement ...
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1answer
163 views

Why was the 307’s pressurisation system removed when it was modified into the C-75, despite the fuel-burn advantage of higher-altitude flight?

The Boeing 307, an airliner derivative of the B-17 heavy bomber, was the first pressurised airliner to enter series production and go into service (hence its bulbous, altogether un-B-17-like fuselage, ...
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1answer
640 views

Why would short-haul flights be pressurised at a higher cabin pressure?

In the article here : https://abcnews.go.com/Health/Healthday/story?id=4507808&page=1 it is claimed that Short-haul flights are usually pressurized at 5,000 to 6,000 feet while long-haul ...
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2answers
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How Cabin Pressures Are Selected?

The pilot puts the cruise altitude to the FMC and the plane auto adjusts the cabin pressure. I know that but I once heard the cabin pressure is set to three thousand feet. Is it true? Why is the ...
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3answers
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Why aren't aircraft cabins pressurized to sea level pressure?

From an article on WHO's website: Although aircraft cabins are pressurized, cabin air pressure at cruising altitude is lower than air pressure at sea level. At typical cruising altitudes in the ...
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1answer
266 views

Is it possible for crew oxygen to exacerbate a flight deck fire?

Crew oxygen is, as I understand it, a very high percentage of purity. Oxygen-enriched air acts as an accelerant to a fire, causing things to ignite which wouldn't in ordinary air, and making fire ...
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1answer
539 views

Why is the alternate static pressure lower than the standard static vent pressure regardless of the venturi effect on both?

I understand that the higher relative airspeed around the body of an aircraft in comparison to the air within the cabin causes the cabin to experience a lower pressure. However, I was just thinking ...
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2answers
521 views

Why don’t double-bubble fuselages cause severe fatigue problems?

In response to my previous two questions about fatigue issues, or the lack thereof, generated by the cusps in double-bubble-fuselaged aircraft (Stratocruiser, DC-9-80), I received a number of answers ...
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1answer
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How much air does a 777-300ER's pressure cabin hold?

I've been wondering how much air a 777-300ER's pressurised cabin holds, but, while most of its specifications are fairly easy to find, the amount of air it contains is not. Does anyone know what ...
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1answer
441 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 ...
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2answers
132 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 ...
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1answer
965 views

Can the pilot stop airflow between cockpit and cabin?

During normal operation the entire fuselage is pressurized equally: An aircraft fuselage does not contain separate compartments with different pressure values in each. The entire vessel is ...
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2answers
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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 ...
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2answers
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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 (...
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2answers
4k 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 ...
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1answer
233 views

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, ...
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1answer
638 views

What's the cabin pressure of a Bombardier CRJ-900? [closed]

In terms of altitude (6000, 7000, 8000, etc), what is the cabin pressure in a CRJ-900?
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1answer
247 views

Why can't I ever get my right ear to pop on descent in a plane?

Whenever I'm flying, there's a period of descent where my right ear just refuses to pop. This has been bothering me for at least ten years. There seems to be a long stage of descent where my ear is ...
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1answer
785 views

Are pressurized passenger aircraft usually completely airtight?

Various sources on the internet indicate that the passenger cabins on pressurised airplanes are not 100% airtight. I'm not talking about ventilation/pressure valves/cabin pressurisation system, but ...
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7answers
20k views

Is it true that a soda can or a bag of chips will pop in a plane at high altitude? [closed]

I've heard some conspiracy theorists claim that if you were to bring a soda can or a bad of chips onto an airplane, they would pop? Is this true? If so, why?
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2answers
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Is if safe/legal for an aircraft to return to cruising altitude after passenger oxygen masks have been deployed?

I was reading reports [1,2,3,4] about a recent Air China flight where one of the pilots was allegedly smoking and, in an effort to prevent the smoke circulating to the cabin, accidentally de-...
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3answers
604 views

Is the increased humidity on modern jets artificial?

Aircraft manufacturer’s including Boeing and Airbus have emphasised on greater passenger comfort owing to an increase in humidity on newer jets such as the 787 and A350 artificial? Or is it a direct ...
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1answer
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Was the safe landing of Southwest flight 1380 extraordinary or expected?

I've been reading with great interest and concern about the recent Southwest flight that resulted in the first fatality in that airline's history. There's one question I haven't seen answered, though:...
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2answers
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How can I calculate the cabin pressure following a decompression?

What are the calculations to determine the level of cabin pressure at a given altitude once the cabin is punctured? I was unable to determine the window size and the flow rate of the compression ...
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1answer
762 views

What are the layers of a pressurized fuselage (cross-section and construction)?

I've looked all over this site, and also Web searches - but I can't seem to find any discussion about, and the construction cross-section of, a commercial airliner's pressurized fuselage wall. Not ...
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3answers
365 views

I have really intense ear pain during descent in commercial flights. Would it be better or worse if I was flying a small non-pressurized plane?

Usually — but not always — after descending in a commercial jet airliner, my ears really hurt for several days, accompanied by minor hearing loss. Nonetheless, I am still in love with aviation. I am ...
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0answers
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Is the air bleeded from the engine to maintain cabin pressure for airlines heated or cooled [duplicate]

Is the air bleeded from the engine to maintain cabin pressure for airlines heated or cooled. If heated, what device is used, if cooled, what device is used and in both cases how much energy does it ...
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2answers
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What was the first commercial aircraft to have a 'built-in' oxygen system?

(Source) Boeing 307 of TWA, the 307 was the first pressurized passenger aircraft. The 307 (c. 1938) flew as high as 23,300 ft, lower than the jets of nowadays, and did not have a built-in oxygen ...
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1answer
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Which was the first pressurized aircraft?

Which aircraft was the first one to fly pressurized? High altitude breathing apparatus, 1918 (source) I mean an aircraft which didn't require to don an oxygen mask above a certain altitude, ...
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1answer
842 views

Can the RAM AIR valve cause depressurization on the CRJ-900?

On the CRJ-900 AIR-CONDITIONING panel there is a RAM AIR switch light which opens a valve and allows air from the ram air scoop to enter the mixing manifold for distribution to both the flight deck ...
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0answers
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What's the reason for “pre-pressurization” of the cabin prior to liftoff? [duplicate]

I'm reading a Citation M2's Pilot Training Manual, and it says: ...When the throttles are advanced for takeoff, the bleed air turns on (if not already on for heating), and the pressurization ...