Mfcttrf

Who are the people reviewing far more papers than they're submitting for review?

Is there a theorem in Real analysis similar to Cauchy's theorem in Complex analysis?

Why does dd not make working bootable USB sticks for Microsoft?

Should I inform my future product owner that there are big chances that a team member will leave the company soon?

What does this Blight Tower UI mean?

Transit visa to Hong Kong

How to draw a Venn diagram for X - (Y intersect Z)?

Unpredictability of Stock Market

In what sequence should an advanced civilization teach technology to medieval society to maximize rate of adoption?

Permutations in Disguise

How often is duct tape used during crewed space missions?

Is it better to use mosfet with gate driver IC or mosfet with lower VGs on

What did the first ever Hunger Games look like?

How clean are pets?

What are the typical trumpet parts in classical music?

Why 1.5fill is 0pt

L and epsilon factors of Gelbart-Jacquet lifts

Impossible Scrabble Words

How to ensure that neurotic or annoying characters don't get tiring on the long run

Why is the car dealer insisting on a loan instead of cash?

In what state are satellites left in when they are left in a graveyard orbit?

Are all men created equal according to Hinduism? Is this predominant western belief in agreement with the Vedas?

Test to know when to use GLM over Linear Regression?

Why are two-stroke engines nearly unheard of in aviation?

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

Does the B787 (Dreamliner) operate with higher cabin pressure?How is the cabin pressure maintained inside aircraft?Can cabin pressure be lower than outside pressure?If the pilot cabin loses pressure, can the pressure difference lock the cockpit door?What's the relation between cabin pressure and altitude?Why is cabin pressure increased above ambient pressure on the ground?What is the rationale behind very short distance flights?What are the structural differences between short- and long-haul airplanes?How can I calculate the cabin pressure following a decompression?How much air does a 777-300ER's pressure cabin hold?

.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;

1

$begingroup$

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 flights are closer to 8,000 feet, according to Thibeault, [M.D., medical advisor, IATA].

But why would this be? My understanding is that the cabin pressure is chosen as a balance of:

• what the aircraft can withstand without slow structural deformations, so that it is functional for many years


• what is most comfortable for the passengers


• most fuel efficient- pumping in air requires some fuel.

With regards to comfort, I should think that low pressures take their toll after a few hours (I think I read 3-9 hours, for people developing altitude sickness symptoms at about 8500ft equivalent cabin pressure).

The only guesses I have at why short-haul flights can operate at higher cabin pressure is:

• the aircraft body won't have as much structural change with a short-term pressure difference




• the plane can 'retain in' air pressure without actively pumping it for some time on the order of hours/ half-hours, so it is not so energetically costly.

cabin-pressure short-haul

share|improve this question

edited 8 hours ago

ymb1

80.4k99 gold badges265265 silver badges434434 bronze badges

asked 9 hours ago

MeepMeep

10611 bronze badge

New contributor

Meep is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  For anyone else who read the title wrong: it says "higher cabin PRESSURE" (= lower cabin altitude)
  $endgroup$
  – J. Hougaard
  6 hours ago
  

  
  
  
  

add a comment
 | 

1

$begingroup$

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 flights are closer to 8,000 feet, according to Thibeault, [M.D., medical advisor, IATA].

But why would this be? My understanding is that the cabin pressure is chosen as a balance of:

• what the aircraft can withstand without slow structural deformations, so that it is functional for many years


• what is most comfortable for the passengers


• most fuel efficient- pumping in air requires some fuel.

With regards to comfort, I should think that low pressures take their toll after a few hours (I think I read 3-9 hours, for people developing altitude sickness symptoms at about 8500ft equivalent cabin pressure).

The only guesses I have at why short-haul flights can operate at higher cabin pressure is:

• the aircraft body won't have as much structural change with a short-term pressure difference




• the plane can 'retain in' air pressure without actively pumping it for some time on the order of hours/ half-hours, so it is not so energetically costly.

cabin-pressure short-haul

share|improve this question

edited 8 hours ago

ymb1

80.4k99 gold badges265265 silver badges434434 bronze badges

asked 9 hours ago

MeepMeep

10611 bronze badge

New contributor

Meep is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  For anyone else who read the title wrong: it says "higher cabin PRESSURE" (= lower cabin altitude)
  $endgroup$
  – J. Hougaard
  6 hours ago
  

  
  
  
  

add a comment
 | 

$begingroup$

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 flights are closer to 8,000 feet, according to Thibeault, [M.D., medical advisor, IATA].

But why would this be? My understanding is that the cabin pressure is chosen as a balance of:

• what the aircraft can withstand without slow structural deformations, so that it is functional for many years


• what is most comfortable for the passengers


• most fuel efficient- pumping in air requires some fuel.

With regards to comfort, I should think that low pressures take their toll after a few hours (I think I read 3-9 hours, for people developing altitude sickness symptoms at about 8500ft equivalent cabin pressure).

The only guesses I have at why short-haul flights can operate at higher cabin pressure is:

• the aircraft body won't have as much structural change with a short-term pressure difference




• the plane can 'retain in' air pressure without actively pumping it for some time on the order of hours/ half-hours, so it is not so energetically costly.

cabin-pressure short-haul

share|improve this question

edited 8 hours ago

ymb1

80.4k99 gold badges265265 silver badges434434 bronze badges

asked 9 hours ago

MeepMeep

10611 bronze badge

New contributor

Meep is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

share|improve this question

edited 8 hours ago

ymb1

80.4k99 gold badges265265 silver badges434434 bronze badges

asked 9 hours ago

MeepMeep

10611 bronze badge

New contributor

Meep is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share|improve this question

edited 8 hours ago

ymb1

80.4k99 gold badges265265 silver badges434434 bronze badges

asked 9 hours ago

MeepMeep

10611 bronze badge

New contributor

Meep is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

edited 8 hours ago

ymb1

80.4k99 gold badges265265 silver badges434434 bronze badges

edited 8 hours ago

ymb1

80.4k99 gold badges265265 silver badges434434 bronze badges

asked 9 hours ago

MeepMeep

10611 bronze badge

New contributor

Meep is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 9 hours ago

MeepMeep

10611 bronze badge

1 Answer
1

active

oldest

votes

5

$begingroup$

For the structural loading, the absolute cabin pressure is not as important as the pressure differential with respect to the outside pressure.

Short-haul flights typically operate at lower altitudes; either because they are operated by turboprop aircraft which have a lower service ceiling, or because there is simply not enough distance to climb to a high altitude and glide back to land. At lower altitudes, the outside air pressure is higher, and thus the cabin pressure can be higher without exceeding the maximum pressure differential the fuselage can handle.

Your other concerns are not really a factor. Only the pressurisation cycle count really matters to aluminium, not the total pressurised time duration. The fuel required for pressurising the aircraft is also not really a factor compared to the energy required to either heat or cool the air for passenger comfort.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

SanchisesSanchises

7,63611 gold badge2828 silver badges6161 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  The Boeing 777 is a long-haul aircraft that can cruise up to 43,000’, but not with a full load of passengers and fuel. At the beginning of a long-haul flight the typical cruise altitude is performance limited to about 29,000-31,000’. At these altitudes the cabin altitude will be only 5,000-6000’.
  $endgroup$
  – Mike Sowsun
  7 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @MikeSowsun Exactly - it's the altitude that determines cabin pressure, not long- or short haul.
  $endgroup$
  – Sanchises
  6 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Thank you for your reply. What do you think is the 'long haul/short haul' round-about cut-off (I realise that it will be dependent on many factors)? Would 2 hour flights, say, generally be flying at lower altitude?
  $endgroup$
  – Meep
  6 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @Meep The long haul/short haul is from the older hub-spoke model, where jets would do long haul and turboprops short haul. This is still true in some places but in other places jets do flights under an hour at high altitude too, much shorter than some traditional short haul flights.
  $endgroup$
  – Sanchises
  5 hours ago
  

  
  
  
  

add a comment
 | 

Your Answer

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "528"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/4.0/"u003ecc by-sa 4.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);



);

Meep is a new contributor. Be nice, and check out our Code of Conduct.

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name

Email

Required, but never shown

StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2faviation.stackexchange.com%2fquestions%2f69730%2fwhy-would-short-haul-flights-be-pressurised-at-a-higher-cabin-pressure%23new-answer', 'question_page');

);

Post as a guest

Name

Email

Required, but never shown

5

$begingroup$

For the structural loading, the absolute cabin pressure is not as important as the pressure differential with respect to the outside pressure.

Short-haul flights typically operate at lower altitudes; either because they are operated by turboprop aircraft which have a lower service ceiling, or because there is simply not enough distance to climb to a high altitude and glide back to land. At lower altitudes, the outside air pressure is higher, and thus the cabin pressure can be higher without exceeding the maximum pressure differential the fuselage can handle.

Your other concerns are not really a factor. Only the pressurisation cycle count really matters to aluminium, not the total pressurised time duration. The fuel required for pressurising the aircraft is also not really a factor compared to the energy required to either heat or cool the air for passenger comfort.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

SanchisesSanchises

7,63611 gold badge2828 silver badges6161 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  The Boeing 777 is a long-haul aircraft that can cruise up to 43,000’, but not with a full load of passengers and fuel. At the beginning of a long-haul flight the typical cruise altitude is performance limited to about 29,000-31,000’. At these altitudes the cabin altitude will be only 5,000-6000’.
  $endgroup$
  – Mike Sowsun
  7 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @MikeSowsun Exactly - it's the altitude that determines cabin pressure, not long- or short haul.
  $endgroup$
  – Sanchises
  6 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Thank you for your reply. What do you think is the 'long haul/short haul' round-about cut-off (I realise that it will be dependent on many factors)? Would 2 hour flights, say, generally be flying at lower altitude?
  $endgroup$
  – Meep
  6 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @Meep The long haul/short haul is from the older hub-spoke model, where jets would do long haul and turboprops short haul. This is still true in some places but in other places jets do flights under an hour at high altitude too, much shorter than some traditional short haul flights.
  $endgroup$
  – Sanchises
  5 hours ago
  

  
  
  
  

add a comment
 | 

5

$begingroup$

For the structural loading, the absolute cabin pressure is not as important as the pressure differential with respect to the outside pressure.

Short-haul flights typically operate at lower altitudes; either because they are operated by turboprop aircraft which have a lower service ceiling, or because there is simply not enough distance to climb to a high altitude and glide back to land. At lower altitudes, the outside air pressure is higher, and thus the cabin pressure can be higher without exceeding the maximum pressure differential the fuselage can handle.

Your other concerns are not really a factor. Only the pressurisation cycle count really matters to aluminium, not the total pressurised time duration. The fuel required for pressurising the aircraft is also not really a factor compared to the energy required to either heat or cool the air for passenger comfort.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

SanchisesSanchises

7,63611 gold badge2828 silver badges6161 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  The Boeing 777 is a long-haul aircraft that can cruise up to 43,000’, but not with a full load of passengers and fuel. At the beginning of a long-haul flight the typical cruise altitude is performance limited to about 29,000-31,000’. At these altitudes the cabin altitude will be only 5,000-6000’.
  $endgroup$
  – Mike Sowsun
  7 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @MikeSowsun Exactly - it's the altitude that determines cabin pressure, not long- or short haul.
  $endgroup$
  – Sanchises
  6 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Thank you for your reply. What do you think is the 'long haul/short haul' round-about cut-off (I realise that it will be dependent on many factors)? Would 2 hour flights, say, generally be flying at lower altitude?
  $endgroup$
  – Meep
  6 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @Meep The long haul/short haul is from the older hub-spoke model, where jets would do long haul and turboprops short haul. This is still true in some places but in other places jets do flights under an hour at high altitude too, much shorter than some traditional short haul flights.
  $endgroup$
  – Sanchises
  5 hours ago
  

  
  
  
  

add a comment
 | 

$begingroup$

For the structural loading, the absolute cabin pressure is not as important as the pressure differential with respect to the outside pressure.

Short-haul flights typically operate at lower altitudes; either because they are operated by turboprop aircraft which have a lower service ceiling, or because there is simply not enough distance to climb to a high altitude and glide back to land. At lower altitudes, the outside air pressure is higher, and thus the cabin pressure can be higher without exceeding the maximum pressure differential the fuselage can handle.

Your other concerns are not really a factor. Only the pressurisation cycle count really matters to aluminium, not the total pressurised time duration. The fuel required for pressurising the aircraft is also not really a factor compared to the energy required to either heat or cool the air for passenger comfort.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

SanchisesSanchises

7,63611 gold badge2828 silver badges6161 bronze badges

$endgroup$

share|improve this answer

edited 8 hours ago

answered 8 hours ago

SanchisesSanchises

7,63611 gold badge2828 silver badges6161 bronze badges

answered 8 hours ago

SanchisesSanchises

7,63611 gold badge2828 silver badges6161 bronze badges

answered 8 hours ago

SanchisesSanchises

7,63611 gold badge2828 silver badges6161 bronze badges