how is it like to breathe oxygen at high alts

[bd32322]

As I am contemplating turbo aircraft - I am wondering how does it feel like to breathe oxygen up at altitude? Do you get tired quickly - are there other physiological symptoms that make it uncomfortable?

 

Thanks in advance

[Parker_Woodruff]

How high?

I only have experience up to FL190, but probably will never fly unpressurized above FL230.  I do have a lot of time breathing through a cannualla between 14,000 and 17,000.  It's not uncomfortable.  Just be ready for some dry nose.

Keep in mind, you're using a mask above 18,000 ft pressure alt.

The speed increases for long cross country flights are more than worth it!

[FAST FLIGHT OPTIONS LLC]

Hypoxia and the related symptoms are going to vary from person to person and the severity of those symptoms will also vary based on altitude and a host of other factors to include the person’s physical condition.  After a long flight @ 12K I might feel tired w/o O2.  If I use the oxygen from takeoff to touch down I actually feel refreshed after the flight. I say 12K because that’s about as high as you could go w/o the O2.  I have on occasion turned it on at flights @ 8K when I started to feel a bit tired.  At 17K it keeps me alert and I don’t find it to be at all uncomfortable which is something I hear pilots complain about from time to time.  The 02 is something I definitely like having in my 231, would never fly w/o it, keeps me feeling fresh at all altitudes and the only negative I could think of is the hassle of having to refill when you get low.

 

[Joe Zuffoletto]

Breathing supplemental oxygen while flying is second nature to me as most of my trips are in the flight levels over the Rockies and Sierras. I've been up to FL250 with no problems, but most of my flights are in the high teens and low 20's. I've never suffered any ill effects.

Even though it makes radio work a hassle, I always use a mask with a rebreather, regardless of altitude. Cannulas dry out my nose and waste oxygen.

[WardHolbrook]

FWIW, here are my thoughts, in no particular order, on the use of O2:

1. 
   
2. Visit an altitude chamber and take a ride. YOU ned to know what YOUR hypoxia symptoms are. Also, symptoms can change so if it's been a few years since your last chamber ride it's probably time to do it again.  
   
3. Buy a pulse oximeter and use it regularly during high altitude flight. 
   
4. Buy a small emergency bottle and mask and keep themt within reach just in case your main system developes a problem. This bottle only needs to contain enough O2 to get you down to a breathable altitude.
   
5. Don't automatically default to the high altitudes just because you can. Flight planning takes on new meaning. One of the flight planning programs or online programs will really help you pick the most efficient altitudes and routes. I use Flitesoft and Fltplan.com. I prefer Flitesoft. 
   

Do you need this stuff to be legal? No, but you do need it to be safe up there. We're not talking a lot of money, Chamber rides used to be free, I think they still are depending upon where you go. The pulse oximeter and emergency bottle aren't budget busters either. Fltplan.com is free and commercial flight planning programs like Flitesoft won't break the bank either.     

[bd32322]

thanks everyone for your replies. WardHolbrook - I like the points you make - good idea. I was planning to fly at whatever altitude gives me the best winds or weather - but not above FL250 probably.

ok now I am back into buying a turbo aircraft mood - just dunno which one

[Parker_Woodruff]

Quote: bd32322

ok now I am back into buying a turbo aircraft mood - just dunno which one

[jlunseth]

O2 smells like, well, O2.  Same smell at altitude as on the ground.

Like Parker, I don't go above FL230 often.  There has to be a reason, like a much stronger tailwind at 23 than at 21 (which is unusual but does happen).  The time of useful consciousness is too short for me at those altitudes.  Not looking at the charts, but it is in the five minute something seconds range.  So you take 2 or 3 minutes to figure out you have a problem, and then not much time left to get down.

But other than that, I fly in the flight levels basically every trip I make over two hours.  One to two hours I will probably pick something between 16 and 19.  Less than an hour I will just stay down under 12, as a general rule, unless it is too rough down there.

One of the magic things about a turbo is that the roughness ends at the tops of the popcorn cumulus, which is around 16.  Above that it is generally glass smooth, so with pax on board who are not GA veterans, I will generally go up to the mid- to high teens just for the smoother ride for them, even on shorter flights.

I use a mask above FL180.  Cannula below.  Pax generally use cannulas regardless of altitude.

[bd32322]

Quote: Parker_Woodruff

 What's your mission profile and what's your budget?

[M20F]

Quote: colojo

Even though it makes radio work a hassle, I always use a mask with a rebreather, regardless of altitude. Cannulas dry out my nose and waste oxygen.

[WardHolbrook]

Quote: JimR

Plus one for chamber training courtesy of the USAF.  I did it here at Tyndall Air Force Base in Florida a few years ago.  I think that there was a nominal charge, but it was only $20 or $30.  Probably the greatest bang from the training buck that I have ever gotten.  They only take us civilians up to FL250, but that is plenty enough to satisfy the purposes of the course.  I remember them telling us that the average time of useful consciousness at that altitude is only around three minutes.  It is a very harsh environment up there, plain and simple.  I'll happily defer to Ward on this, but I thought that I also remembered them telling us that one's personal symptoms of hypoxia remained constant throughout one's life.  Mine were a loss of color vision and a tingling in the rear end.  No jokes please!  Hey, it could be worse.  One of the common symptoms that the Air Force listed was "brown outs".  Yes, it is what you think that it is. 

Jim      

[M20F]

Quote: WardHolbrook

[WardHolbrook]

Quote: M20F

[M20F]

Quote: WardHolbrook

What is the difference between a non-pressurized GA airplane and a pressurized GA airplane above FL250? 

[elanvert]

I fly a 252 and I would never take it above 23K it is just plain commun sense, it is certified up to 28K but what if something went wrong up there, before you realise it it is too late!!  only need to remember the Pain Stewart's accident. Even pressurized aircraft can give it up

[WardHolbrook]

Quote: M20F

What is the difference between a non-pressurized GA airplane and a pressurized GA airplane above FL250? 

[29-0363]

There is far more to high altitude flight than just hypoxia - most people think that Decompression Sickness (aka DCS or "the bends") is a hazard for deep sea divers, but it can and does affect pilots as well. Some people will show symptoms from a long exposure at FL180 (4-5 hours), while others might operate at FL250 without any symptoms at all.

I believe females are more affected than males because of their tissue make-up (I didn't want to use the word fat), and unpressurised high altitude flight within 24 hours of scuba diving can be serious if not fatal. Older folk may also be more affected.

For further reading search on Avweb under aeromedical topics, or Wikipedia under Decompression Sickness.

[Awful_Charlie]

It's far from a fail safe, but when I go above FL150 or so, I set the altitude hold to FL100 or so and set a RoD in too.  The idea is that I just have to hit the two buttons on the KAS297 to get me to a better environment.  If I'm hypoxic I reckon I've got a better chance of hitting two buttons over retrieving & donning a spare o2 set and it working as intended.

To the OP, I don't have a problem with Oxysaver cannulas for a few hours at a time, I find them more confortable than  a mask, which I use as by the regulations.  A few hours up high with o2 and I fell better after landing than after a few hours at say 8000 without.  Staying hydrated with a mask is more difficult, and your shaving habits will have an effect on how comfortable a mask or cannula sits.  Otherwise, it can get pretty cold up there, and my Bravo heater isn't effective enough when the OAT gets much below -30 or so, and somewhere about that temp the windows also start to freeze the condensation on the inside.  Shorts and tee shirt it is most certainly not!

[PTK]

Quote: bd32322

As I am contemplating turbo aircraft - I am wondering how does it feel like to breathe oxygen up at altitude? Do you get tired quickly - are there other physiological symptoms that make it uncomfortable?

 

Thanks in advance

[johnggreen]

Wthin the last couple of years, I read a story about a Mooney pilot (ex Air Force pilot) who took his Mooney to 28m.  No unusual circumstances were present.  When he started down, he noticed the syptoms of the bends, called center and by the time he landed, he was almost completely incapacitated.  They air lifted him to a decompression chamber and saved his life.

Different strokes for different folks, but after studying all the available info years ago, I decided that 18m is my limit.  Yes, I am erring on the side of conservatism, but that's my decision.  The limitiations of  single pilot, single engine, piston, non-pressurized aircraft are in my opinion significant.

The only reason I'm flying a Bravo and not a pressurized turbo prop is simple; I can't afford it.

Jgreen

[xftrplt]

This topic has been discussed at length on this forum. Suggest a search for "hypoxia", and read the previous threads.