High altitude, non-turbo flight

[Hank]

52 minutes ago, Ragsf15e said:

I think you’ll find very little loss of simple mental tasks and you probably won’t notice a lack of judgment.  You likely won’t have significant hypoxia like people talk about in the altitude chamber if you’re just cruising at 10-12k even though there’s likely some degradation there.  You’ll really need to use a pulseox repeatedly to see the dip.  What you’re most likely to notice is the change in fatigue after (or even during) a flight. Those yawns you mention?  Sure you’re not tired?  How do you feel in the evening after a long flight, maybe a little tired?  O2 makes a huge difference there.

I used to feel.bad after long flights above 7500 msl. Then I switched from a clamp-o-matic headset to a QT Halo in-ear headset, and it all cleared up. Guess it wasn't low oxygen after all . . . . Been that way for over 10 years now. Just flew almost 7 hours a couple of Saturdays ago, and 3.5 last Saturday at 8500. No issues.

[Ragsf15e]

9 minutes ago, Hank said:

I used to feel.bad after long flights above 7500 msl. Then I switched from a clamp-o-matic headset to a QT Halo in-ear headset, and it all cleared up. Guess it wasn't low oxygen after all . . . . Been that way for over 10 years now. Just flew almost 7 hours a couple of Saturdays ago, and 3.5 last Saturday at 8500. No issues.

Do you use a pulse ox just to see?

[Hank]

29 minutes ago, Ragsf15e said:

Do you use a pulse ox just to see?

It spends most of its time on the back seat. Need to remember to use it sometime. Didn't have one back in the headclamping days.

[LANCECASPER]

4 hours ago, rturbett said:

I took a deep breath before climbing to altitude... or I was hypoxic and couldn't read it correctly!  If I recall correctly, my instructor was at 94%  

I also did some repetitive mental tasks to "judge myself" along the way...

For my normal flying- which is still being determined - I'm usually below 9k

 

Taking one deep breath could have kept your SpO2 high for a couple minutes, but not long. 

There are a lot of areas where self-examination is a good idea. Judging your own mental acuity is not one of them - you are using your own mental acuity to judge your mental acuity, what if it's off? Thinking that it's not, without the need of an outside objective opinion,  is an indication that it is.

[Pinecone]

2 hours ago, LANCECASPER said:

There are a lot of areas where self-examination is a good idea. Judging your own mental acuity is not one of them - you are using your own mental acuity to judge your mental acuity, what if it's off? Thinking that it's not, without the need of an outside objective opinion,  is an indication that it is.

Like people drinking.

 

[wombat]

I get sleepy when hypoxic.   Didn't know that was one of my major symptoms until I I did the altitude chamber.  Now I do and if I get sleepy in the plane, the first thing I do is check my oxygen level.

[Ibra]

Worth going with somone on O2 and removing own O2 to see personalised symptoms and reactions, I did this with someone in his Bravo: up and down between 8kft-22kft on various profiles (auto-pilot, hand-flying, cruise...) 

It's interesting that he was +25 years older, heavy smoker, lived his whole life in flat land, yet he coped very well

I would not trust my abilities to notice hypoxia alone without O2 alarm or someone else nearby to lose it first or to weak me up 

Edited May 20, 2024 by Ibra

[dkkim73]

I just received my Wellue pulse-ox ring. In the first 20 minutes, very impressed. Seems to maintain a signal and report well. Have trialed some other options. Have been waiting for this, and some test flights with my current "baseline" oxygen rig, before I venture into mask altitudes. A simply finger backup is also good. 

I would respectfully recommend *not* relying entirely on subjective criteria. 

D

ETA: and yes, take opportunities for physio (chamber) flights to experience symptoms, or ROBD (reduced-oxygen breathing devices) if you can't get to a chamber. And remember to allow for changes in age and your physiologic "journey" as well. 

[rturbett]

9 hours ago, LANCECASPER said:

Taking one deep breath could have kept your SpO2 high for a couple minutes, but not long. 

There are a lot of areas where self-examination is a good idea. Judging your own mental acuity is not one of them - you are using your own mental acuity to judge your mental acuity, what if it's off? Thinking that it's not, without the need of an outside objective opinion,  is an indication that it is.

Couldn't find the smiley emoji to let you know I was joking on the deep breath.  Had a good conversation through the flight with a very experienced instructor talking about expectations.   I will be getting oxygen in the future, and likely before I try anything like this on my own. 

[McMooney]

12 hours ago, Hank said:

I used to feel.bad after long flights above 7500 msl. Then I switched from a clamp-o-matic headset to a QT Halo in-ear headset, and it all cleared up. Guess it wasn't low oxygen after all . . . . Been that way for over 10 years now. Just flew almost 7 hours a couple of Saturdays ago, and 3.5 last Saturday at 8500. No issues.

I notice i feel, "off", after flying for extended periods at  > 8k ish.  watching the pulse ox, i never go below 90/92 ish and it really only takes a few deep breaths to bring it back up.   started taking a puff or two of ox every now and again, just to avoid that bleh feeling

[Shadrach]

8 hours ago, McMooney said:

I notice i feel, "off", after flying for extended periods at  > 8k ish.  watching the pulse ox, i never go below 90/92 ish and it really only takes a few deep breaths to bring it back up.   started taking a puff or two of ox every now and again, just to avoid that bleh feeling

I wonder if it’s not a combination of things. 
As a flat lander (I live at 524msl) who occasionally travels to high altitude destinations and spends several days above 8000’ doing strenuous activity with no acclimation, its hard for me to get my head around someone feeling “off” over 4 or 5 hours sitting at >8k. Do you feel off after sitting in an airline cabin pressured to 9 K?

I suspect that most GA pilots are moderately dehydrated after an extended flight. None of us want to deal with peeing in the plane, so we avoid hydrating in flight.

 

 

[Steve Dawson]

If you have a pulse oximeter try breathing in through your nose and exhaling through your mouth however purse your lips to restrict exhaling. This should help a little with O2 intake. This increases pressure on the membrane in your lungs to push O2 into your bloodstream. It works well if you're on a cannula. (Doctors feel free to correct) 

I've noticed as much as 6% O2 intake 

[Fly Boomer]

11 hours ago, dkkim73 said:

I just received my Wellue pulse-ox ring. In the first 20 minutes, very impressed. Seems to maintain a signal and report well.

Let us know your experiences as you begin to use this thing at altitude.  I have been eyeballing the Wellue for a while, and I need a little push to open my wallet (again).

[dkkim73]

3 hours ago, Fly Boomer said:

Let us know your experiences as you begin to use this thing at altitude.  I have been eyeballing the Wellue for a while, and I need a little push to open my wallet (again).

Will do. I'm also going to wear it around a bit, and probably overnight, to see what kind of gaps or vulnerabilities it might have. 

Have been waiting for a good wearable before going higher than 17k. I'll probably try popping a bit higher on the Eastbound leg of my next commute. 

ETA: the auto on/off when you wear it or take it off is surprisingly helpful. 

[dkkim73]

4 hours ago, Steve Dawson said:

If you have a pulse oximeter try breathing in through your nose and exhaling through your mouth however purse your lips to restrict exhaling. This should help a little with O2 intake. This increases pressure on the membrane in your lungs to push O2 into your bloodstream. It works well if you're on a cannula. (Doctors feel free to correct) 

I've noticed as much as 6% O2 intake 

That maneuver *definitely* works. A significant mechanism is increased "recruitment" of the alveoli, the little air sacs where "the magic (of gas exchange) happens". They are collapsed but open up when you pressure-breathe yourself as above, and when you breath more deeply, particularly at the lung bases. Unsure how much the absolute pressure increase helps in terms of partial pressure driving gas exchange (given the limited pressures we can generate with our chest esp. during inspiration, would have to look it up) but it certainly doesn't hurt. 

I have used the above to "get by" in terms of avoiding mild hypoxia at bordlerline altitudes when we brought the wrong cannulas on a demo flight. 

A pressure-demand or other positive pressure system helps with the above by delivering external boost. E.g. the common narrow panel military regulators. 

Another important practical physio point to digest: as you climb, the partial pressure of CO2 decreases along with O2, and the lesser absolute value of CO2 will decrease respiratory drive. So you just won't breath as often. So a very basic thing to do is remember to breath more regularly than you feel compelled to, and a bit more deeply. 

If you do both of the above, you can boost your effective oxygenation by a surprising amount at middling altitudes. 

HTH

 

[Will.iam]

I second the wella o2 oxygen ring. In fact i really think it’s a must have as it vibrates at any set level you set and is continuously taking 1 second measurements so you know the second your o2 drops. Case in point. Was climbing to fl210 with my oxygen concentrator like i have done before, and passing through FL190 this time i heard a weird clunk misstep of the concentrator and on my next breath instead of getting my puff of O2 like i normally do i got nothing. And the machine did not cycle again and then i heard a beep from the concentrator and the screen was flashing a warning that before i could read it i felt my finger buzzing and i looked at my O2-ring and my O2 was dropping past 89% that got my immediate attention and i refocused on swapping to my main built in storage tank and after 2 breaths my O2 shot back up passed 89% where my O2 ring was set at and it stopped buzzing my finger but i was still perplexed as to why my oxygen concentrator stopped working. Since i was down to one source of oxygen i requested from center that i would like to descend so i could troubleshot my oxygen issue. As i was decending passing through 18k the concentrator started working again and i leveled off at 17k and switched back to the concentrator to limit my use of my main tank. The concentrator worked for the rest of the flight at 17k. The O2-ring really helps redirect your priority if you get sidetracked with a different issue, much better than if i had a oximeter on my finger. Who knows how long it would have been before i noticed it or remembered to check it especially if i was going hypoxic as fast as i was. It’s like watching a pot for it to boil over. Always seems to do it when you stop staring at it. And flying you can not afford to get channel focused at the expense of other duties. The vibrating ring is priceless for that very reason. Getting your attention when you need it immediately. Like the sensorcon for detecting and bringing to your attention CO gas in cabin by beeping and flashing red lights!

i need to do some more tests at altitudes above 18 to see if i can recreate the issue. My current theory is all the times i have gone past 18k before were in the summer and the cabin was still hot. This time it was winter time and i had on a coat and did not heat up the cabin and had the concentrator on the floor instead of the seat. I’m thinking it might have gotten too cold and stopped. Also i was trying the airbud tips on my cannula and it might have messed it up. I also noticed that at 18k as i was climbing the puff at level 6 on the concentrator was not big enough to fill up my lungs so i was not getting a full breath and that was working against me. Later i took the airpod tips off and the flow of air by the puff allowed me to take more natural deeper breaths which increased my O2 levels.  

[LANCECASPER]

3 hours ago, Will.iam said:

I second the wella o2 oxygen ring. In fact i really think it’s a must have as it vibrates at any set level you set and is continuously taking 1 second measurements so you know the second your o2 drops. Case in point. Was climbing to fl210 with my oxygen concentrator like i have done before, and passing through FL190 this time i heard a weird clunk misstep of the concentrator and on my next breath instead of getting my puff of O2 like i normally do i got nothing. And the machine did not cycle again and then i heard a beep from the concentrator and the screen was flashing a warning that before i could read it i felt my finger buzzing and i looked at my O2-ring and my O2 was dropping past 89% that got my immediate attention and i refocused on swapping to my main built in storage tank and after 2 breaths my O2 shot back up passed 89% where my O2 ring was set at and it stopped buzzing my finger but i was still perplexed as to why my oxygen concentrator stopped working. Since i was down to one source of oxygen i requested from center that i would like to descend so i could troubleshot my oxygen issue. As i was decending passing through 18k the concentrator started working again and i leveled off at 17k and switched back to the concentrator to limit my use of my main tank. The concentrator worked for the rest of the flight at 17k. The O2-ring really helps redirect your priority if you get sidetracked with a different issue, much better than if i had a oximeter on my finger. Who knows how long it would have been before i noticed it or remembered to check it especially if i was going hypoxic as fast as i was. It’s like watching a pot for it to boil over. Always seems to do it when you stop staring at it. And flying you can not afford to get channel focused at the expense of other duties. The vibrating ring is priceless for that very reason. Getting your attention when you need it immediately. Like the sensorcon for detecting and bringing to your attention CO gas in cabin by beeping and flashing red lights!

i need to do some more tests at altitudes above 18 to see if i can recreate the issue. My current theory is all the times i have gone past 18k before were in the summer and the cabin was still hot. This time it was winter time and i had on a coat and did not heat up the cabin and had the concentrator on the floor instead of the seat. I’m thinking it might have gotten too cold and stopped. Also i was trying the airbud tips on my cannula and it might have messed it up. I also noticed that at 18k as i was climbing the puff at level 6 on the concentrator was not big enough to fill up my lungs so i was not getting a full breath and that was working against me. Later i took the airpod tips off and the flow of air by the puff allowed me to take more natural deeper breaths which increased my O2 levels.  

I have had an Inogen since 2017 but there's not a chance in the world I would use it at FL180 and above. I notice that it starts to lose it's ability to produce breathing oxygen pretty rapidy above 16,000. I've used it up to 17,500 once. But in addition to that the FAA in their documents say that you have to use a mask, and not a cannula, at FL180 and above for good reason.

https://www.faa.gov/pilots/safety/pilotsafetybrochures/media/oxygen_equipment.pdf

[Schllc]

I had a very unpleasant experience at 25k with a mask. Would not do things the same way again if I ever even went that high in the Mooney. 
On the off chance I did want to go that high, I would have an extra mask rigged and ready, and I would be with another person. These days I occasionally may venture out to 21 for a nice tailwind, but the climb and small differences for anything over 19k are usually not worth the time to climb or the fuel. Look at your planning in ForeFlight. Often the gain is minutes and the fuel consumption is higher. 
Point is that it is seldom worth the risk to go that high. Tailwinds seldom justify the altitude, and there is no terrain in the US that would push you that high. 
The acclaims sweet spot is really 16-19k. 

[hazek]

This year was my first year flying above 13k where O2 is legally required all the time(it’s after 30min above 10k) in EASA land. I had a finger oximeter before but on flights it just wouldn’t work. On the ground it provided a reading just fine but in the air even at something like 6k it wouldn’t work on any finger. It’s as if the blood was pulled out of hands.

So I bought one more expensive that was advertised working under tougher conditions and now this one works most of the time - sometimes I have to wait a bit to get a reading. It’s called Ninon 9590. I use Aerox’s Oxysaver cannula so I don’t go above 18k. So far highest I went was 17.5k - the problem usually for VFR is getting the clearance into class C.

Anyway while I have the oximeter, what I found works better is just my Garmin smartwatch and the oximeter as a double check. I had the Venu 3 but I wanted better so splurged on the D2 Mach 1 Pro that has all the pilot stuff, among which is the Fly activity. If I use that, I can have it setup to take continuous, or rather frequent, O2 readings and with the display always on during the activity I can always just glance at my watch. Surprisingly it shows my SpO2 higher than the Ninon finger oximeter, and I suspect it’s due to the blood leaving my hands when I fly. I also noticed the setting on the flowmeter need to be a bit higher than what I fly at for me to have good SpO2 and feel good. Not sure why that is. I’m too chicken to test sats below 92% and I also start to feel “something” which stops when I increase the flow. I should probably do the chamber somewhere to learn my hypoxia symptoms.

 

[Ventus4]

I normally fly my F with O2 and >10k.
This is almost mandatory to fly ifr in europe south of the alps.
I verify many times the performances and they match the ‘66 POH within the specify tolerance:
Here the example:


I used mph on the g5 to stay coherent with the poh.
As you can read 166 mph tas @11k with 9.4usgh
while the poh at 10k was 171 with the same Fuel Flow.
In that trip you can read 158kt gps which is the big advantage of flying high many times


Inviato dal mio iPhone utilizzando Tapatalk

[cliffy]

You're never too old (or too many hours ) to learn new things.

Gotta say  this is one good thread with a variety of experiences, risk/gain values and hardware info.

I harp on O2 and hypoxia in non-pressurized airplanes to be very careful of hypoxia sneaking up on you. 

Just like the Payne Stewart Learjet crash, hypoxia can and will sneak up on you and you may never know it until its too late!

One trip in a  US Air Force altitude chamber made me a believer.

What did I learn here?  Using the Vue ring and a smart watch. I use a finger tip unit but I don't go above 10,500.

I know my symptoms and they start at a  lower altitude as the years go by. 

I have an old Vue ring but its been dead for years. I just may jump for a new one now.

Also hadn't thought about the "pressure " breathing by exhaling. Going to test that now.  

My D model doesn't do well at 14,000 in the summer (high DA)  12,500' is about all it can do effectively in  the summer with

any up and down drafts. Not enough reserve HP. Haven't been up there since 9/11.