18000 ft, no oxygen

[bluskis]

I have been reading some First World war writings by British and German pilots, and noted they often flew at 15,000 to 18,000 ft.

Does anyone know if oxygen was used during the conflict, or what effect it had on their fighting abilities if it wasn't?

[Tinstaafl]

No oxygen, and yes, it reduced their abilities.

[PeterThePilot]

They must have been fairly hardy individuals, I was under the impression that there was not enough oxygen to sustain life above eight thousand feet to sustain life, hence that is the altitude aircraft are pressurised at.

Also, an engineer once told me you could just about survive being in the unpressurised cargo hold of a 747 at thirty thousand feet if you wore a few warm jackets, but you would be struggling to breathe.

Remember that chap who survived a flight from India to London heathrow in the whell compartment of a 747? :eek:

[cwatters]

I spent about an hour at 14000 ft in a glider over Switzerland once. The instructor in the seat behind me behind me kept asking if I was OK. I was more than OK, I was "£$%^^ great.

We floated up and down along the sunny side of a line of cloud formed by wave lift off the mountain - fantastic. On the way down we saw climbers halfway up the mountain. They were wearing cold weather climbing gear, heavy boots etc We were wearing tee shirt and shorts. We were a bit cold but it wasn't that bad under the glass. No O2 used.

[Background Noise]

10,000 ft is the generally cut-off for aircraft not equipped with oxygen. 8,000 is for comfort and oxygen levels but there's still enough above that for life - Everest has been climbed without oxygen.

[koogar]

Used to ferry planes, one in particular, think a cessna 208 or 182 or something, from Fresno to Palomar. I flew the route all the way at 12000ft to get the quickest route over the San Gabriel mountains and LAX. wonderful view, no probs. Also a good friend flys a taxi and when empty or freighting it regularly goes to 14000ft over alps with no problems, and he smokes. So if you are reasonably fit and health, it can be ok, but perhaps better not to try, as it could be a bad way to discover you are not as fit as you thought.

[northwing]

The higher you go above 10000ft, the shorter your legal time of useful consciousness. It depends a lot on individual fitness and age as well of course. Also, aclimatisation helps - hence athletes doing altitude training. The blood thickens in response to thin air in order to carry more oxygen. Typically, most people are OK for about half an hour at 14000ft but once you get up to 30000ft ish you are down to 12 seconds which is the time it takes the blood to get from the lungs to the brain.

The highest altitude for sustained life was demonstrated by some Andean silver miners. They lived at 17000 ft, I believe, and walked up to the mine entrance at 18000 ft each day before descending to the workface at 17000 ft inside the mountain. The mining company moved their village up to 18000 ft to save the time taken to walk to work. This was OK for the miners who went down to 17000 ft each day, but their families complained of persistent headaches because they were at 18000 ft all the time.

[englishal]

12500' and no 02 is no problem. Regularly fly up to this in the US, above 12500 for more than ½hr you're meant to use 02. Hardly notice it, and I'm by no means the fittest bloke on this planet [and I smoke:D ] Talked to a ferry pilot who was bringing an aircraft back from Japan to the US via russia, he forgot to switch the 02 supply on, and once airborne he was ******ed as it was behind the fuel bladders. Still, he was up to FL190 due to the MEA's en-route and the only major side effect he reported was a blinding headache when he landed....

Cheers
EA:D

[Flap 5]

I have climbed Mt. Kinabalu (13,455ft), along with many other people, with no ill effects. Reinhold Messner (probably spelt wrong) climbed Mt. Everest with no oxygen many years ago and others have done it since. Climbing takes a lot of effort. Just sitting in an aeroplane requires very little effort. So your figure of 8,000ft is way out. That figure is for comfort and to avoid having to pressurise the cabin to sea level which would be a much greater pressure differential.

[bluskis]

I find that at FL105/110 I have to double check I have selected the correct frequency on changes as I have made mistakes in the past.

These chaps had to make split second decisions to keep alive.

When was oxygen first recognised as a desirable aid to high flying?

[mstram]

cwatters

>I spent about an hour at 14000 ft in a glider over Switzerland once. The instructor in the seat behind me

>behind me kept asking if I was OK. I was more than OK, I was "£$%^^ great.


Hmm, maybe you *were* OK, but, are you aware that one of the symptoms of hypoxia is "euphoria". ?


"Personality Traits – There may be a release of basic personality traits and emotions as with alcoholic intoxication (euphoria, elation, pugnaciousness, overconfidence, or moroseness)."

http://www.mountainflying.com/hypoxia.htm

[*Lancer*]

Many of these stories told here seem to indicate that flying at altitudes in the 'teens' is ok... Well, it's a dangerous game you're playing, as your performance level is almost certainly not 'fine'. The lack of oxygen would also cause an element of euphoria that is unlikely to be noticed, preventing you from realising any performance shortcomings.

Even flying at 8000 reduces performance. Eyesight is significantly affected by hypoxia (even at that level)... try taking a gulp of pure oxygen after 3 hours at 8000 at night - you'll be suprised.

Airliner warning systems provide a 'hard' warning when the cabin altitude exceeds 10000 feet. The automated passenger oxygen system is activated passing 14000 feet. Above 45000 when pressurised it is a requirement in many airlines and countries to have the oxygen mask sitting around the pilot flying's neck - because the time of useful consciousness is so short, there's too much risk in not having it 'at the ready'.

northwing, time of useful consciousness isn't a legal term, it's a medical one...

Sure, walk up a mountain without the stuff, but flying is even more isolated...

Lancer

[411A]

One very simple fact....those who fly an un-pressurized aircraft above ten thousand feet for extended periods without supplemental oxygen...are very foolish indeed.
Many have learned the hard way.....:eek:

[Panama Jack]

In my previous job, I spent most of my time flying between 20,000 and 23,000 in unpressurized airplanes (for 5 to 6 hour legs). So did my collegues.

It is hard to eat a meal with the O2 mask on. It is not hard to breathe-- you don't feel like you are drowning, but you are feeling the effects. At 23,000, I would feel the need to slap the mask back on my face within a minute and it felt so good when I did. Some people could last longer. I noticed that this would vary for me from day to day-- depending on how well I slept, how tired I was, etc.

The biggest problem was not using enough O2. Some guys were really stingy. Others wanted to show how little O2 they could use. One bonehead actually bragged that he did a whole 2½ hour flight without O2-- but I've always wondered about this guy. The Company did little to help, and actually promoted this concept as a cost savings.

One guy came to me (older pilot) and told me he was getting DCS. He was convinced of it. I told him to try cranking the O2 open. No way, he was suffering from DCS. I insisted. He followed my suggestion, and guess what-- he was fine! We had another guy, first flight on the line, who used so little O2 (around 300 psi for a 5 hour flight) he felt sooooooo sick when he landed that he swore he couldn't handle the high altitude, that he was getting DCS also. He looked like he was at death's doorstep. It took some time to convince him that it wasn't DCS, that he needed to crank the O2. Guess what, next time I saw him he had a big smile on his face.

The problem with hypoxia is you can get it using O2, if you don't use enough. Most guys said they were not suffering hypoxia, but after prompting them to crank the flow up they realized how much better they were were feeling and that they were actually somewhat hypoxic. Unlike being pregnant, hypoxic is not a situation where you "are" or "you are not".

Remember, the biggest consumer of O2 is your brain. As a result, before you get the tingling in your fingers or legs, your brain is somewhat impared. It actually keeps you from realizing how degraded your skills are. Kinda like people who feel they are just as good after a drink-- I don't feel dizzy-- I am not affected yet!

[GlueBall]

Cruising at 39,000 feet MSL the cabin altitude may be as high as 8500 feet....for many hours. Clears up your sinuses!

Let's not forget places like La Paz, Bolivia, where people work and live, and where jets every day land and takeoff on a pavement at 13,300 feet MSL; the pavement at Cusco, Peru, is at 11,000 feet; Quito, Ecuador is at 9,200 feet....

At all these places I haven't seen any visitor walk around with an oxygen bottle yet. :p

[compressor stall]

http://www.thebmc.co.uk/world/mm/mm2.htm

A good link to the physiological effects of how to acclimatise to altitudes of the mid 20thousand feet mark. It'f for ground based folk though - the whole issue is acclimatisation. If you dont acclimatise, you wont survive for too long.

As discussed people have successfully climbed Everest without O2, however thier exposure to such extreme altitudes is limited to as short a time as possible.

Yours truly has heard one of UK's finest mountaineers saying that he finds marijuana helps him to acclimatise....and one of Australia;'s best has had a joint on top of Mount Everest....

:confused:

[ZK-NSJ]

i have been trekking in nepal, and for part of the trip we were walking above 16500ft with no probs

[Panama Jack]

Glue Ball and Compressor Stall,

What you guys are saying is true.

There is an aclimatization process that goes on. People who live at high altitude have a higher red blood cell count. The red blood cells are those who carry oxygen throughout your system. If these people were to go to live at sea level for a few weeks and then return to their homes in the high country, they would once again have to readjust and it would take a few weeks.

When the Olympics were held in Mexico City, the athletes who had lived and trained at high altitude faired better than those who lived at sea level.

As far as drug use (and for pilots I recommend using supplimental oxygen over smoking joints to deal with the high altitude flight environment), consider that the South American indians in the high terrain chew coca leaves (the same stuff that is used to produce cocaine) in part to deal with the high altitude environment.

[saudipc-9]

I did the chamber run of 25'000 about 6 months ago. I lasted about 3 min without O2 before I started to lose my ability to think straight. TUC at that altitude is about 3-4 min if I remember correctly. It got to the point where I did not realize that the instructor had put me back on 02.
Very dangerous to anyone who does not use 02 above 10'000 or 12'500 depending on your regs

[Human Factor]

Not often I agree with 411A, however he is right to say you are taking a chance above 10k without O2. Depends quite a lot on individual fitness.

As far as I'm aware, the airport at La Paz is one reason why manufacturers set the masks to drop at a cabin alt of 14,400ft. From experience, don't stand up to quickly when disembarking there!!:eek: