Pilots and oxygen

[stiz]

One thing i've noticed is that in most of the plane addons out there today they either make you put on your oxygen or pressurize the cabin at about 8k-10k feet, now my question is .. how come ww1 pilots managed to get to 20kish feet (later in the war) without it? was it just that it took them so long to get to that hieght and the body got used to it? the fact they where in an open cockpit and not in a greenhouse? should the "you must your oxygen on before 11k ft or you pass out and die!" be tweaked??




Why the question?? cos i keep forgetting to turn the rudy oxygen on!

 

[Lotus]

Hi Stiz. Sorry if I've contributed to this particular problem.

I'm not sure about the circumstances of the pilots you mentioned, but I can offer my own direct experience with high altitude in the open air. About seven years ago I took an eight day trek in the Indian state of Sikkim, right in the middle of the Himalayas. The hike involved an ascent to 17000 feet over 4 days, to the Goechala pass (where you come face to face with Kangchenjunga, the third highest peak in the world). I'm a reasonably fit guy (and was fitter then) and altitude sickness hit me very hard at about 16800 feet. Within 15 minutes of the first symptoms I was virtually unable to walk without falling over, let alone do even simple mental arithmetic. Along with it comes extreme queasiness and blurred and slightly dimmed vision. It took all my energy and concentration to simply retie one of my boot laces haha.

It's a deeply unpleasant experience. The guide I had for the trip, a wonderful Nepali gent, was raised at 15000 feet, has lived there his whole life, so he was perfectly fine at any altitude, and the two British girls on the trek also had no serious problems, though they were looking quite pale and feeling a bit drunk at the end as well. I think it depends a lot on physiology.

My flight instructor also experienced this when climbing Mount Rainier (14,400 feet), and was virtually incapacitated by it. It's no joke, that's for sure. All you want to is sleep, but if you do there's a chance of slipping into a coma. The only solution is rapid descent, and the sickness leaves as quickly as it comes after a few hundred foot drop.

Anyway, long story short, with acclimatization time it's certainly possible to breathe and function normally well over 18000 feet. Flying doesn't involve much exertion like hiking, but then the ascent is much more rapid in any airplane. I think any reasonably fit person at rest is fine up to 13000-14000, but after that it's a crap shoot.

-Mike

 

[paulb]

I guess when flying it also depends upon how long you stay at that altitude. I have been told that 15k for a short time is OK.

Just found this -
<TABLE border=2 cellPadding=8 width=420 align=center><TBODY><TR><TD width="100%">

Average Effective Performance Time for flying
personnel without supplemental oxygen:
15,000 to 18,000 feet ..........30 minutes or more
22,000 feet ...............................5 to 10 minutes
25,000 feet .................................3 to 5 minutes
28,000 feet............................2 1/2 to 3 minutes
30,000 feet .................................1 to 2 minutes
35,000 feet ............................30 to 60 seconds
40,000 feet ............................15 to 20 seconds
45,000 feet ..............................9 to 15 seconds​

</TD></TR></TBODY></TABLE>

 

[txnetcop]

Some time ago I lent my services and aircraft to Wings For Christ. We were working with Christian Flights International in Argentina, Honduras, Guatemala etc., flying medical emergency patients and medical supplies. One village in particular, Olacapato was well above 12500 ft and we had to fly at 15k for approach. We flew many cases from villages and townships that were above 11k for days on end. We had portable oxygen bottles on-board but I don't remember ever using, unless I was suffering from hypoxia myself. We were reminded in our briefings about the dangers of hypoxia but I don't believe any of the pilots suffered from it.

I also flown from Leadville, CO up to the peaks around Alma CO on a photography mission without the use of oxygen in C-152 though of course I had it available. One of the pilots in another aircraft started getting headaches and feeling nauseous and went on oxygen. I know we were flying at altitudes from 10-13k for several hours. So I guess it comes down to physical conditioning and the amount time you actually spend at altitude.
Ted

 

[CodyValkyrie]

Generally speaking in Accusimmed aircraft, I put on my mask at 10K out of habit. You will find however that you can often get a lot higher, say 15K or even much more before you start seeing any side effects of hypoxia observed. I remember one flight where I didn't see the effects until roughly 17K.

Accusim will always warn you however... or at least should.

If your oxygen mask isn't working correctly you better descend FAST. You also better hope you catch the system if it isn't working.

It is important to check the oxygen bottles before every flight and confirm that the oxygen works on the ground if possible. According to my notes it was common for pilots to put on their masks during engine starts, especially with he canopy open (in case of fire, etc). Having the mask on made it a bit easier to breath while all that smoke surrounded the cockpit. I believe however most pilots generally found those masks uncomfortable as hell, which is one reason they often didn't wear them until much higher altitudes were reached.

Of course, I am speaking strictly to WWII aircraft.

 

[scotsman]

At the end of WWI, German pilots had oxygen equipment on board.
The pic shows a fighter pilot with his Fokker D VII in 1918.

Mike

 

[Daube]

They sure had oxygen bottles in their planes, as explained above.

In a totally different context, sometimes at the parachute club, we manage to organize special jump sessions at higher altitude than usual (need special authorizations from regionnal air traffic controllers, not easy).

Usually, we jump at 12.000 feet (4.000 meters), and since we do not stay up there for long, we never use oxygen. However, the presence of an oxygen bottle is mandatory in our plane for any jump higher or equal to 6.000 meters (18.000 feet). We need something like...I don't remember, perhaps 10 to 15 minutes to go from 4.000 to 6.000 meters, and I can assure you that you really need a bit of oxygen when you are up there. Not 100% time oxygen, but a breath or two every 2-3 minutes are needed.

 

[stiz]

At the end of WWI, German pilots had oxygen equipment on board.
The pic shows a fighter pilot with his Fokker D VII in 1918.

Mike

ahh never knew that! do you know if the allies had em?

Generally speaking in Accusimmed aircraft, I put on my mask at 10K out of habit. You will find however that you can often get a lot higher, say 15K or even much more before you start seeing any side effects of hypoxia observed. I remember one flight where I didn't see the effects until roughly 17K.

hmm mine never does it tends to just black me out straight away ... wonder what i've messed up and broken this time! :isadizzy:

 

[lucas81]

Slightly OT, but also worth mentioning is that the German ww1 recon crews had electric-heated suits. THeir Rumpler C.VII Rubild recon planes were easily operating at the 21k feet only to descent to about 7000 ft to take pictures of the selected area far away the frontline. I am not sure about the Allied crews and how they were equipped - mostly the SE5a and Sopwith Dolphin pilots who were operating at high altitudes along with some Bristol Fighters as well.

 

[Daveroo]

i had watched a tv show awhile back,said a bottle was kept in the plane (biplanes from wwi era) and they put a hose in their mouths...for O2

 

[idancesafetydance]

I had to use Oxygen once in a Grob 103 Sailplane on a cross country flight once in Colorado. Got tugged up to 10k feet, and thermalled/waved up to 14k. I carried oxygen, as I had a feeling that, with the conditions of the day, I'd need it, but I forgot to carry these special diaper lined bags to uh... drain the lizzard in, and it was a 5 hour flight.

That was a stupid mistake.

 

[Bomber_12th]

I have always found it amazing the expeditions up Mount Everest, and the ability of some people to reach such great heights without oxygen assistance, at least not until the last 2,000 ft or so. The height of the mountain peak is roughly 29,000 ft.

I've always held the 10,000 ft mark in my mind, for putting on oxygen in an aircraft, from films like the original Memphis Belle documentary and Twelve O'clock High - which I believe many others can attribute this to as well.

 

[CodyValkyrie]

hmm mine never does it tends to just black me out straight away ... wonder what i've messed up and broken this time! :isadizzy:

Even oxygen starvation is Accusimmed...

If your sound is up, you should hear your pilot breathing heavily. That is the first sign. Usually you get a couple of chances, before he goes nuts breathing and blacks out. You might even notice a zooming type effect.

These are the indicators. They are subtle, but they are there.

 

[TeaSea]

US FAA requires supplemental oxygen for pilots above 12,500 FT MSL over 30 minutes or more. Required full time at 14,000 MSL. Supplemental oxygen required for passengers over 15,000 MSL. Like PaulB says there is a time factor. There are specific guidelines for the amount of oxygen (which I don't know), but any oxygen will help. Several times I have flown on C-130's above 10000 with the ramp open putting HALO jumpers out. We commonly just passed the O2 bottle around and took a hit every few minutes, just to avoid the dizzies (please note, I was a passenger, not crew).

It's the sudden ascent that really has the impact I think.

I didn't realized Accusim was that detailed....hmmmmm....might have to plunk down some change .....

 

[SADT]

Even oxygen starvation is Accusimmed...

If your sound is up, you should hear your pilot breathing heavily. That is the first sign. Usually you get a couple of chances, before he goes nuts breathing and blacks out. You might even notice a zooming type effect.

These are the indicators. They are subtle, but they are there.

I loved the "Go nuts breathing" part. Its really funny to watch your view zoom in and out as he (the pilot) struggles for breath. Not so funny when your B-17 at 17000 feet, rolls hard over directly above mount Rainier......

 

[Daube]

I loved the "Go nuts breathing" part. Its really funny to watch your view zoom in and out as he (the pilot) struggles for breath. Not so funny when your B-17 at 17000 feet, rolls hard over directly above mount Rainier......

Indeed, the first time for me was in the Accusim P-47. I could hear the breath first, but I didn't understand what it meant. Then after a short while, I started getting the view problems with the fluctuating zoom... Then I took a look at the altitude gauge and understood I had to activate the oxygen mask for the pilot. This feature was totally unexpected, I was pleasantly surprised.

 

[roger-wilco-66]

Hehe, an interesting aspect of oxygen comes to my mind. I've read in several books (one was a B-17 related book) that hungover aircrews used the oxygen in the morning to overcome their bad condition. Never tried that myself (I don't get hungover enough , so I really don't know of there's something to it.

Cheers,
Mark

 

[Quixoticish]

Hehe, an interesting aspect of oxygen comes to my mind. I've read in several books (one was a B-17 related book) that hungover aircrews used the oxygen in the morning to overcome their bad condition. Never tried that myself (I don't get hungover enough , so I really don't know of there's something to it.

Cheers,
Mark

It gives you a bit of a rush and clears your head but the effect quickly dissipates.

We found that the only way to really beat a hangover if you've had a bit too much to drink was to stick a saline drip in overnight.

 

[Sieggie]

All flight crews of pressurized military aircraft must go through High Alt training and the Chamber. It will really open your eyes to the effects of oxygen deprivation. Things slowly lose color as the pressure drops and you don't notice until you put the mask on and take a hit on the old O2. Everything flashes back into color again in an instant. It is very unnerving.

A quick hit on the O2 will help with mild motion sickness from turbulence also.

Dave

 

[djscoo]

8-10k is certainly survivable without oxygen on foot. Going from ground level to 10,000 in an airplane is probably more of a shock on the system than if you were walking up, acclimating as you go. I climbed 2 fourteeners over the summer and never had any issues with altitude sickness(as Lotus said, it's largely personal as well). I'm sure the need for oxygen has everything to do with the speed at which you travel to that altitude.