Dumb question about airplane cabin pressure from a pilot or tech

[watermock]

I know will sound crazy, and I could ask my brother, but I was watching Payne Stewarts long ride after he lost cabin pressure.

I know that you need oxygen if you lose cabin pressure, but wouldn't the cabin lose oxygen at 39,000 feet as it's circulated at that altitude or is there an oxygen regulator feeding in oxygen...I imagine there would have to be, but I have never thought about it. It would seem that the cabin would be pressurized, but wouldn't have enough oxygen just by being pressurized.

[kappys]

If you're talking about oxygen masks, then all you need is a regulator that bleeds in around 3-4 L O2 per minute (about 16-20%) to feel fine and dandy. What you exhale would be mostly lost

[broncosteven]

I know will sound crazy, and I could ask my brother, but I was watching Payne Stewarts long ride after he lost cabin pressure.

I know that you need oxygen if you lose cabin pressure, but wouldn't the cabin lose oxygen at 39,000 feet as it's circulated at that altitude or is there an oxygen regulator feeding in oxygen...I imagine there would have to be, but I have never thought about it. It would seem that the cabin would be pressurized, but wouldn't have enough oxygen just by being pressurized.


There is very little oxygen at 39,000 feet, they pressurize the cabin so as not to lose oxygen & or heat. you can fly in an unpressurized cabin but would then need an oxygen mask & tanks & lots of long undies.

The russians lost a couple of Cosmonauts during reentry (in the 60's) due to a pressurization valve being opened at the wrong time during reentry. Their blood boiled due to lack of O2 in the cabin, same as if you went on a space EVA with out a Space Suit. The inside of cabin was fine other than the 2 or 3 dead men.

Deke Slaton actually opened the same type of pressure valve early during re-entry (though not early enough to kill them) on the last Apollo mission where they linked up with the russians in earth orbit. They were far enough down where it only let in some Toxic fumes from the reentry that came from plasma burning off the capsule. all 3 guys got sick but they lived & Nasa hushed it up for a while.

[watermock]

So you just breath the oxygen that exists at takeoff the whole way? Doesn't that get used up in a packed airliner? On a long flight, say LA to Japan wouldn't the CO2 build up too high?

[broncosteven]

Not sure exactly how they do it. I am sure they have a CO2 scrubber that is in the ventilation system somehow. They do add O2 & carry O2 for the masks.