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Cabin altitude of an A350 or 787 at 40,000 feet?

Cabin altitude of an A350 or 787 at 40,000 feet?

Old Jan 31, 2023, 5:21 pm
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Lightbulb Cabin altitude of an A350 or 787 at 40,000 feet?

All,

Not sure if this is the right section to post. But curious if any experts can tell me what the effective cabin altitude is at 40,000 feet for an A350 or 787?

From my understanding, a 77W at 36,000ft has a cabin pressure of around 6000 feet (which is lower than the max of 8000ft). Curious how "comfy" an A350/787 actually is at normal cruising altitude?

Thanks!
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Old Feb 3, 2023, 6:15 pm
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The Boeing 787 has a design cabin altitude of 6,000 ft, the A350 is set even lower at 5,500 ft. The cabins are pressurized and maintain this level regardless of cruising altitude, be that 30,000 ft or 40,000 ft.

That's one reason (the other being increased humidity levels and the reduced noise footprint on those two aircraft) why they feel more 'comfy' to passengers.
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Old May 2, 2023, 8:15 am
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Originally Posted by bhomburg
The Boeing 787 has a design cabin altitude of 6,000 ft, the A350 is set even lower at 5,500 ft. The cabins are pressurized and maintain this level regardless of cruising altitude, be that 30,000 ft or 40,000 ft.

That's one reason (the other being increased humidity levels and the reduced noise footprint on those two aircraft) why they feel more 'comfy' to passengers.
Apologies for the late response - thanks so much for the reply! How does that compare to an A380 which is also pressurized around 6,000 ft?
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Old May 9, 2023, 4:09 pm
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Originally Posted by thelister
Apologies for the late response - thanks so much for the reply! How does that compare to an A380 which is also pressurized around 6,000 ft?
Its identical, you are at 6000ft so the partial pressure of oxygen is the same. The amount of fresh air change over on more modern aircraft is determined by the number of pax the aircraft is told it has. This regulates the amount of recirculated air mix with fresh air to maintain humidity to a comfortable level.

The only other differences are the sources of air. Airbus still uses bleed air tapped off form the compressor sections of engines. Boeing have got what is effectively 4 dysons that draw and compress air prior to sending it to the air conditioning packs. Form then on the process in the bootstrap system is the same.
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