was talking to this guy the other day, very familiar with flying. so he said the cabins are pressurized. which i knew. but he said they are pumped up to about the same pressure as you would find at 10,000 feet. which is why its so dry up there and your ears pop. complicated discussions about humidity (rh, ab, h20vap, dew pt etc) aside. i was thinking they must pump raw oxygen in there, because ive never heard of someone getting altitude sickness while flying, but the air's still less dense, so it must be a different mix. and is in no way helping with acclimitazation. yes? no?

What I've heard is that the cabin pressure is the equivalent of 7,000 ft. altitude. I also learned on one flight that the air conditioners for the cabin supply the air pressure (they said that one of the air conditiners wasn't working so we had to fly at a lower altitude). I doubt that they increase the amount of oxygen in the air, but I could be wrong there, so the flight probably does help a bit with acclimatization.

I asked the pilot of a Southwest 727 this question and his remark was 8000'. So I'd guess 7000 to 8000' is probably accurate. When I fly into Denver I count my 3 hour plane trip as acclimatization time. Then I try to drive up to Georgetown once I get in which is at 8000' for a nights sleep.

sealevelmick wrote:i was thinking they must pump raw oxygen in there

You know they used to allow smoking on planes

yup, most planes its 800' feet, but the new Boeing 787 its 6000' because of the new technology.

-CS

drjohnso1182 wrote:

sealevelmick wrote:i was thinking they must pump raw oxygen in there

You know they used to allow smoking on planes

My father used to use an oxygen mask to keep his pipe lit while flying in non-pressurized planes.

As for the lack of altitude sickness on a plane, a lot of people feel it. That's why people get headaches and don't feel great on long plane rides. For the most part, people aren't on planes long enough to get any real signs of AMS (and most people don't get very sick at the pressure levels inside of pressurized planes.)

FortMental wrote:I've worn my altimeter once during a flight... the altitude/pressure curve topped out at around 7,200 ft. There was periodic minor variation over time but nothing extreme. Kinda interesting and worth knowing firsthand, anyway.

I also wore my Suunto once during flight and it registered 8000' plus or minus.

lasvegaswraith wrote:

FortMental wrote:I've worn my altimeter once during a flight... the altitude/pressure curve topped out at around 7,200 ft. There was periodic minor variation over time but nothing extreme. Kinda interesting and worth knowing firsthand, anyway.

I also wore my Suunto once during flight and it registered 8000' plus or minus.

x2. Measured ~8000' with my Suunto. Man I'm a dork...

Most of us don't get altitude sickness on planes because we're just sitting in a chair. Put in a gym with stairclimbers and we'd notice a difference from our sealevel performance.

jimlup wrote:I asked the pilot of a Southwest 727 this question and his remark was 8000'. So I'd guess 7000 to 8000' is probably accurate. When I fly into Denver I count my 3 hour plane trip as acclimatization time. Then I try to drive up to Georgetown once I get in which is at 8000' for a nights sleep.

Southwest flies only 737 series aircraft. But really, 6,000-8,000 feet equivalent barometric pressure is the norm. Sit on your ass, you don't feel it but run up and down the aisle, you'll feel it, especially after the air marshall takes you down...

oxygen isn't flammable... but it is necessary for stuff to burn.

kiwiw wrote:oxygen isn't flammable... but it is necessary for stuff to burn.

Fill a room with 100% oxygen and suddenly a lot of things become very flammable.

Hmmm . . . a couple of years ago I flew cross country with my altimeter and I don't think it went above 5500'. A better economy and cheaper fuel?

Ditto, last time I flew with an altimeter, it measured around 5500 ft as well. I was surprised because I thought normal air pressure is generally between the 7000-8000 ft equivalent.

No extra oxygen is added. The pressurisation increase the relative amount.

And yup it's pretty taxing to exert oneself when flying. (I joined the Mile High club).