Flying GA (unpressurised) aircraft at higher altitudes

[Wrist Watch]

Hi,

recently I've been doing some longer navigation flights, and for convenience with regard to terrain/airspace, chosen flight levels such as 115, 105, or 095, depending on direction. I've noticed that after some time in cruise I started to yawn, lose incentive to proactively scan the surroundings, and just wanted to get comfy in my seat.

At first I thought it was isolated but after arriving at my destination airports somewhat tired every time, I figured it might have something to do with altitude. I've lived my whole life near sea level so I might not be accustomed to prolonged stays at reduced oxygen levels.

I've read some reports on here of people using supplemental oxygen from FL080 or FL050 at night... Is it really necessary? What's your take on it, any similar experiences or suggestions?

[Above The Clouds]

Are you getting headaches, tingling in your hands, a feeling of well being, euphoria, finding it hard to concentrate, spots in front of your eyes, these and other symptoms are the on set of hypoxia which are exaggerated if you smoke, are of older age and less fit than you used to be. Be very careful because hypoxia will creep up on you unexpectedly, try googling it.

[dirkdj]

A portable oxygen bottle is highly recommended. Even at FL90, a flight of more than two hours is much more comfortable with oxygen and cannulas. At night, going on oxygen, even at FL50, is like switching on the lights on the ground. You can have your portable bottle refilled at a scuba station (be sure they do 100% oxygen) for the price of two beers.

[airwave45]

I've found that using O2 via a cannula makes longer flights less tiring.
have quite a few 5+ hour flights this year usually at fl080 to fl160 with O2 they are a non issue.

Had a few last year without O2 and the downsides range from just tiring to mild headaches to inability to process mild complexity.

using a modern metered supply system such as provided by Mountain High (I'm sure others are available) means your O2 lasts a stunning duration and makes a huge difference.

You can operate quite high without O2, but why bother ?
flights are easier and quantifiably safer on O2.

If not yet convinced, try some simple arithmetic next time you have spent an hour above fl080, you'll be horrified at your decrease in ability.

I put the system online above 6k now, costs sweeties to run and adds minimal hassle.

[Jonzarno]

You might look at Mountain High O2D2 pulse demand regulator and cannulas:

Aviation Portable Oxygen Systems - Mountain High Aviation Oxygen Supply

[mary meagher]

Yes indeed, for a very comfortable way of dying, its hard to beat apoxia...general well being, don't care, pleasantly intoxicated (that word contains the essence, doesn't it!)

If you are a smoker, generally fat and unfit, getting on in years, a functioning oxygen system will certainly help....it is also good for hangovers.

My first experimental flights at altitude in a glider, at Deeside gliding club, I was floating happily in the wave at about 14,000, with the oxygen system turned on half way between 2 and 4...found out later that this halfway meant there was NO OXYGEN being supplied. Luckily my flying skills had declined somewhat and I was unable to maintain altitude, so descended to lower levels.
Never did like being dependent on systems that can be screwed up by simple mistakes!

So when I did eventually manage to achieve diamond height, at 20,300 feet above the airfield, that was it, never again. Don't like scuba diving either.

[Romeo Tango]

When younger and more foolish (and more healthy) I used to do occasional long trips up to about 14000'. I found that rather than being euphoric I got very crotchety and swore at the aircraft more than usual, decisions were slow and difficult to make. Since then I have used O2 cannulas and had a much nicer time.

[sharpend]

If I recall, the RAF rules are:

10,000 feet daytime - hypoxia
4,000 feet - night vision goes.

8000 feet for passengers.

[Pilot DAR]

I've done a number of non pressurized high altitude flights, and they have reminded me why pressurized aircraft are popular. I know that the lure of the high must be answered, but after a few times way up, you'll be content with the middle altitudes while flying non pressurized aircraft. O2 does make a really pleasant and safe difference, so take it and use it liberally....

[Piper.Classique]

I seem to be fairly comfortable up to FL100 or so. Beyond that I find I am very tired after the flight. I took the cub to 195 once, just for fun. Used a portable O2 set. Best bit was hearing some heavy asking «you've got a what at what flight level?»

[wsmempson]

10-12,000 ft I find fine without O2, but wear a portable meter on my finger just to be sure. I'm relatively fit, and ski at 10,000ft plus at least twice a year, without hypoxia. However, after a 5hr flight at over 10,000ft or above, I feel quite washed out the following day.

[cats_five]

There is a lot of variation between individuals in their respose to low oxygen levels regardless of fitness, fatness & so on, but the suggestion of the Mountain High kit and the pulse oximeter on the finger are excellent. This is what a lot of glider pilots use for wave flying, which goes up to FL190 or beyond in the wave boxes. It's carry-on kit so you don't need to worry about the paperwork.

[FullWings]

I use the MH kit and it’s superb. Just come back from two weeks flying in the Alps and one medium-sized O2 bottle lasted for the whole trip - and that’s in a 2-seater.

You just fit the cannula, turn on the electronics and leave it for the rest of the day. When you’re flying half a wingspan from the rock at 12,000+, you need your blood nice and saturated to keep your brain working properly.

You can fly without supplemental oxygen up to quite high altitudes but the degradation in your performance is real and there are possible long-term effects with damage to the oxygen-starved bits of your tissues...

[bad bear]

A lot of the research in to how we react to reduced O2 was done about 60 years ago and may have been wrong. Some of the experiments were in a small decompression chamber with an observer breathing pure O2 sitting next to the subject. The exhaust from the observers breathing is thought to have artificially raised the concentration of O2 in the chamber and skewed the results.

There is a good section on this issue in Jean-Marie Clement's book "Dancing with the wind"

Current thinking is to use O2 from take off if the flight is going above 6,000' which with modern "mountain high" EDS equipment uses very little O2 but just enough to keep the pilot thinking well.

bb

[fwjc]

Any recommendations for reliable pulse oximeters? Thank you in advance.

[lasseb]

I bought one at www.dx.com. works like a charm. Recommend by a doctor friend of mine. He compared it to is clinic stuff and found they agreed with his expensive version. http://www.dx.com/p/finger-pulse-oximeter-black-gray-2-x-aaa-290773#.VcJ9MBr8JDs

[Pace]

American pilots have better lungs than we do up to 12500 unlimited up to 14000 for 30 minutes without supplementary oxygen.
14000 oxygen all the time and the poor old American PAX do not need to be on oxygen until 15000

I fly pressurised now but used to be OK up to 14 unpressurised

Pace

[fwjc]

lasses - Thanks for the recommendation, I have one on order

[IdiotPilot]

I can't go above 6k without a tingle and a light headed feeling. I smoke a little, just a little, and I think that has something to do with it. I hope when I quit smoking I'll be able to handle it eventually.
I would never go to 10k without oxygen like some people I know are doing. Especially with pax aboard.

[Pace]

Idiot Pilot

Just be sure thats altitude and not anxiety nerves and over breathing which can also cause light headedness and tingling