Flying with oxygen : recommended also for 20.000 plus feet?

[Raffi]

My instructor,  an airline pilot , would not advise me to go to the higher flight levels , FL 150 plus with oxygen. He thinks it's dangerous , especially above FL200... what do you guys and ladies of course think about this.. do or don't? 

 

[N201MKTurbo]

I would imagine his concern is the lack of backup oxygen. 

I can do 15000 without oxygen for quite a while, but people are different. You should practice your commercial spiral if you haven't recently. Go up to FL200 with an instructor, hand him your O2 mask and see if you can get down to breathable air without issue. 

[N201MKTurbo]

And if that goes well, go back to FL200 and have him randomly unplug your mask without you knowing it and see if you can get down to breathable air after you figure out you are not getting any oxygen.

[N201MKTurbo]

Keeping one of these in your seat back would be a good idea.

https://www.amazon.com/Boost-Oxygen-Supplemental-All-Natural-Respiratory/dp/B077NQ8MSX/ref=asc_df_B077NQ8MSX/?tag=hyprod-20&linkCode=df0&hvadid=642170619269&hvpos=&hvnetw=g&hvrand=727207665593304534&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9030089&hvtargid=pla-1959191443364&psc=1&gclid=EAIaIQobChMIprLmm6K5_gIVPS2tBh3AiAK6EAQYBSABEgKyOPD_BwE

[Yooper Rocketman]

I routinely fly above that with O2; not doing so pretty much negates the advantages of a turbo.  Absent a turbo, the speed loss based on reduced engine performance doesn't make much sense unless crossing mountains, the Great lakes, or topping weather.  I have done FL230 and FL24 when the winds present some real benefit and flying over Lake Michigan in the winter.  I own a Pulse Oximeter and check Oxygen Sat's pretty regularly on everyone in the cabin.  Lately on my Upper Michigan to Florida trips, I have been using FL180/FL190 to conserve O2 for the round trip without refilling (my refills are free at home and $75-$100 off field).  Most times, especially going SE, the winds are better on the trip down rather than the trip back.

If you have never done it, I would suggest you get a system and get comfortable with it lower, then experiment with it higher over time.  Over my 30 years of flying I have encountered a few hypoxic events, so I know the symptoms, which is a great safety enhancement to the Pulse Oximeter.   Your CFI has a valid concern because becoming Oxygen deprived above 20k has much more serious consequences.  

Tom

 

[aggiepilot04]

2 minutes ago, Raffi said:

My instructor,  an airline pilot , would not advise me to go to the higher flight levels , FL 150 plus with oxygen. He thinks it's dangerous , especially above FL200... what do you guys and ladies of course think about this.. do or don't? 

 

I think 15,000 ft is way too conservative, but I'd understand to argument for above 18. I had a very reputable Mooney mechanic tell me once that he would stay below 18. At the time, my engine would occasionally miss up high, but another mechanic later found that an incorrect (unpressurized) mag was installed.

I will occasionally fly higher than 18 if the winds justify it, and I will tell you, it takes a long damn time to get down from FL250 should a situation necessitate it. At a minimum, frequent checks on a pulse oximeter are a must and backup oxygen is also a good idea. I also heard a wise person once say (can't remember if it was on Mooneyspace or elsewhere) that you shouldn't fly over any weather that you wouldn't fly through. When I first heard that, it didn't occur to me that even the freezing level can be a 15-20 minute descent away.

The glide distance of flying high is nice, especially in the mountains. Just like any other tradeoff, you have to weigh all of the factors in your decision making and leave yourself an out.

[exM20K]

I agree with @Yooper Rocketman and @aggiepilot04.  Generally I’m at 16 or 17,000 form my long trips.  If there is a really good weather reason to go higher, I will occasionally do so.  Mask is not very comfortable and makes drinks or snacks inconvenient.

When I was on the cusp of a C340 purchase, a high altitude endorsement was part of the transition training.

https://www.flyingmag.com/guides/how-to-earn-a-high-altitude-endorsement/

while our planes don’t require that, it’s not a terrible idea.  Also it is worthwhile to familiarize yourself with the emergency descent procedures.

 

[Pinecone]

A good idea would be to do a chamber ride if possible.  Best is one of the chambers that actually reduce the air pressure.  The portable one where they adjust the O2 level would be a close second.

When I did my chamber ride in the USAF, I was the guy that was functional at 25000 feet until they gave up.  I traveled to La Paz, Boliva (airport is 13,000 feet) and had no issues.

But lately, not so much.  So I go on O2 around 8,000 feet.

I would have no qualms about flying over FL180, but can't due to Basic Med.  But would seriously consider carrying a couple of those Boost containers.

[wombat]

I did one of the non-pressure chambers with the FAA, where they use an oxygen concentrator.      Here is a video of it.

During this event I realized that many of the symptoms I had experienced in previous flights were medium intensity hypoxia.   I'm quite healthy and figured that like most things my ability to deal with hypoxia would be significantly above average.  But it's not.  I'm actually quite a bit worse than average.     So when I fly with oxygen, I also fly with a pulse oxymeter.

 

 

[hais]

3 hours ago, N201MKTurbo said:

I would imagine his concern is the lack of backup oxygen. 

I can do 15000 without oxygen for quite a while, but people are different. You should practice your commercial spiral if you haven't recently. Go up to FL200 with an instructor, hand him your O2 mask and see if you can get down to breathable air without issue. 

And hopefully the G1000 hypoxia mode will trickle down eventually...

[Fly Boomer]

4 hours ago, Raffi said:

My instructor,  an airline pilot , would not advise me to go to the higher flight levels , FL 150 plus with oxygen. He thinks it's dangerous , especially above FL200... what do you guys and ladies of course think about this.. do or don't? 

 

Mooney test pilot for the M20K 252 said he had to take the 252 up to 28,000 to get the speed the marketing department had already decided upon (252 MPH).  Also said he would never do it again for the reasons your instructor named.  If I was going to go into the flight levels, I would want one or two backups for oxygen.

[wombat]

What's the failure rate for the built-in O2 system?     What is the price of failure if you do nothing?  What's the price of failure if you mitigate it with some different options? (Carrying a second pilot with a separate O2?     Using a pulse oximeter?)

 

If I'm flying with oxygen, I use my pulse oximeter and only take it off long enough to reposition it onto maybe a finger or something.  For me, that is a satisfactory mitigation.   I would also be satisfied to to mitigate by flying with another pilot on the same system or a non-pilot on a separate system.

But this has all been below FL180, we'll see how I feel after I start getting up a little higher.

 

There is *always* a safer option.   You can always just taxi off the runway, abandon the airplane, go home and go to bed.    So the question is where does the risk of the activity meet your risk tolerance and your budget for risk management?   As long as the activity is legal (which is the government's statement about where you are not allowed to accept the risk regardless of your personal preferences) it's really for you to decide.

[Fly Boomer]

3 minutes ago, wombat said:

But this has all been below FL180, we'll see how I feel after I start getting up a little higher.

In the low 20s (22,000 for example) your Time of Useful Consciousness (TUC) is 5 minutes.  That's for rapid decompression, which I assume would be similar to a sudden loss of oxygen.  That means, if you are average, you turn into a drooling idiot in 5 minutes after the event.  Probably will take at least a couple of minutes to notice that something is amiss.  You can't get down to good air fast enough.  A second (portable) bottle to back up the factory bottle is pretty cheap insurance.

https://en.wikipedia.org/wiki/Time_of_useful_consciousness

[Schllc]

Years ago I was flying home and while planning my flight realized there was a 70knt tailwind at 25k, directly on my tail. Pretty hard to pass up in a plane capable..
I was alone, had the nice blue silicone mask with a microphone, so I filed for 25k and off I went. 
I was cruising along and I looked down in my lap and saw this little black disk. 
At the time the plane I was flying was an ultra with the precise flight conservers, and I thought the disk looked like the adjustment dial on the outside of the unit. 
After a few seconds of fiddling with it, I realized I was trying to put it back together, but it wasn’t apart…. By the grace of god I realized that what I was doing made no sense whatsoever and I engaged the vertical descent for 1400fpm and still to this day do not recall the next two or three minutes. 
What I do recall is being level at 8,000 ft with atc calling me asking intentions. I hit replay on the g1000 and listened to me responding to them and taking instruction. I did not sound like myself, but I was responding. I do not remember any of this…

After my wits were about me again I looked down and realized my arm had gotten wrapped around the o2 hose going to my mask and had inadvertently pulled the grommet out of the front of my mask at 25,000ft.  The disk was the grommet, and if one was completely cogent, would never had mistaken it for anything else.
I don’t know how long it had been pulled out, or how long it took me to notice something was wrong.  The flight recorder only goes back about 2.5 minutes on a constant loop, so that’s all I could listen to.  I don’t know how long the entire event lasted, but I did realize how close I came to being a bad story. 
 

There is certainly more elevated risk at those altitudes, and one must be very vigilant, aware and have some routine to check yourself very regularly. 
I personally stay 19k or below if I am alone, and will only go to 25k with someone else and if we pick up enough time to really make a difference. 
This isn’t my recommendation or suggestion, it’s merely a personal minimum in my Mooney, or any non pressurized airplane. Things can deteriorate much quicker than you would like to believe…

Last thought on this story…    
I was embarrassed by this.  I felt foolish, like my arrogance and confidence led me to a bad choice that could have killed me.
I finally opened up and told the story to a pilot friend of mine and he told me I should share, because perhaps someone could benefit from hearing my mistake.  I sure hope it does, because I still feel foolish. 

[Ragsf15e]

6 minutes ago, Schllc said:

Years ago I was flying home and while planning my flight realized there was a 70knt tailwind at 25k, directly on my tail. Pretty had to pass up in a plane capable..
I was alone, had the nice blue silicone mask with a microphone, so I filed for 25k and off I went. 
I was cruising along and I looked down in my lap and saw this little black disk. 
at the time the plane I was flying was an ultra with the precise flight conservers, and I though the disk looked like the adjustment dial on the outside of the unit. 
After a few seconds of fiddling with it, I realized I was trying to put it back together, but it wasn’t apart…. By the grace of god I realized that what I was doing made no sense whatsoever and I engaged the vertical descent for 1400fpm and still to this day do not recall the next two or three minutes. 
what I do recall is being level at 8,000 ft with atc calling me asking intentions. I hit replay on the g1000 and listened to me responding to them and taking instruction. I did not sound like myself, but I was responding. I do not remember any of this…

After my wits were about me again I looked down and realized my arm had gotten wrapped around the o2 hose going to my mask and had inadvertently pulled the grommet out of the front of my mask at 25,000ft.  The disk was the grommet and of one was complete cogent, would never had mistaken it for anything else.
I don’t know how long it had been pulled out, or how long it took me to notice something was wrong.  The flight recorder only goes back about 2.5 minutes on a constant loop, so that’s all I could listen to, so I don’t know how long the entire event lasted, but I did realize how close I came to being a bad story. 
 

There is certainly more elevated risk at those altitudes, and one must be very vigilant, aware and have some routine to check yourself very regularly. 
I personally stay 19k or below if I am alone, and will only go to 25k with someone else and if we pick up enough time to really make a difference. 
This isn’t my recommendation or suggestion, it’s merely a personal minimum in my Mooney, or any non pressurized airplane. Things can deteriorate much quicker than you would like to believe…

Last thought on this story…    
I was embarrassed by this story.  I felt foolish, like my arrogance and confidence led me to a bad choice that could have killed me.
I finally opened up and told the story with a pilot friend of mine and he told me I should share, because perhaps someone could benefit from hearing my mistake.  I sure hope it does, because I still feel foolish. 

Nothing foolish about that at all.  Good story for everyone and how we all learn.  Thanks.

[Schllc]

5 hours ago, exM20K said:

I agree with @Yooper Rocketman and @aggiepilot04.  Generally I’m at 16 or 17,000 form my long trips.  If there is a really good weather reason to go higher, I will occasionally do so.  Mask is not very comfortable and makes drinks or snacks inconvenient.

When I was on the cusp of a C340 purchase, a high altitude endorsement was part of the transition training.

https://www.flyingmag.com/guides/how-to-earn-a-high-altitude-endorsement/

while our planes don’t require that, it’s not a terrible idea.  Also it is worthwhile to familiarize yourself with the emergency descent procedures.

 

16-19 really is the sweet spot for the acclaim. You get a little more speed up higher, but seldom enough to make it worth the trade off. 

[Fly Boomer]

20 minutes ago, Schllc said:

After my wits were about me again I looked down and realized my arm had gotten wrapped around the o2 hose going to my mask and had inadvertently pulled the grommet out of the front of my mask at 25,000ft.  The disk was the grommet and of one was complete cogent, would never had mistaken it for anything else.

Great story, and great ending.  Thanks for sharing.  It seems to me like many of my big learning moments in flying (and maybe life) have been associated with a near miss.  

[N201MKTurbo]

7 minutes ago, Fly Boomer said:

Great story, and great ending.  Thanks for sharing.  It seems to me like many of my big learning moments in flying (and maybe life) have been associated with a near miss.  

There was someone around here who talked about a pilot being annealed. He said that if you think you have been annealed, you haven’t. If you have been annealed, you know it for sure. The things that make you annealed are something that nobody wants to experience. 

[exM20K]

@Schllc Thanks for sharing.  I consider the O2 system to be the weakest link in the chain for high altitude flight; there are just too many connections and fragile points.

This wreck, and the loss of an Acclaim and its pilot on the way to a MAPASF PPP in Atlantic City are reminders that hypoxia awareness and a backup supply are very, very important once over 17,000, where your TUC gets very short.  

 

I did the PROTE Chamber at the Mooney Summit in 2019 (i think it was then) and hope the organizers this year can schedule it again.  I'm in pretty good shape, but I was playing with yarn and unable to math pretty quickly.  Knowing my symptoms is very helpful.

-dan

[Yooper Rocketman]

I found it tough going from 300 knots pressurized, 3.5 hours from the U.P of Michigan to Spruce Creek in Florida (1100 NM with routing) to 5.5 in the Rocket.  So, when buying my Rocket if I find tail winds on the way down I like flying high.  We do that trip every month from November until April for two weeks, then back to my dealership to work double time for the next hiatus.

I have had two hypoxic events since I bought my Rocket back a year ago, both detected by symptoms before the pulse Oximeter.  On the way to Ashville in October, at FL230, I felt minor symptoms, checked the pulse ox and I was low.  I checked the flow unit on my tubing, found it was normal gut I still dialed it up.  After a few minutes I still didn't feel right so I checked again, flow meter was really high so I'm thinking WTH?  As I am grabbing the adjustable flow unit on the O2 tubing I finally realize the o-ring was leaking out the shaft of the adjustable knob, badly.  I took the mask off and shoved the leaking flow unit up to my nose, I could feel instant improvement and called Chicago Center (I was over Lake Michigan).  No answer after 3 tries and they were not that busy.  WTH?  I looked at my wife, who was trying to give up her mask to me knowing how serious this was, and said, OK, enough of this.  I called Guard and got a response immediately, explained I NEEDED TO GET DOWN TO A BREATHABLE ALTITUDE IMMEDIATLY due to an oxygen issue. This guy asked a bunch of questions and then went off line for probably 2 minutes to approve my descent.  To be clear, my sats were back in the 90's, I had plenty of O2, so it wasn't an emergency, but it was very challenging holding the O2 leak to my nose, hitting the push to talk button and communicating all at the same time with my left hand (oh, and I had bumped the trim switch reaching for the PTT so was hand flying with my right hand).  If I had not gotten my O2 sats in the 90's I would have squawked 7700 und just gone down!!

Once down to 11,000 and back with ATC (instead of Guard) I was asked to call a number and they clearly said it was just to check on me (this would be several hours later).  After landing in Ashville, after dark, I called the number and the Supervisor's only concern was how his crew handled it.  I told him I was thankful but thought the urgency of his controller handling Guard was not very timely, considering the situation.  I suggested he have a conversation about hypoxia dangers with him.  He was appreciative of the feedback and I suspect he had already reviewed the tapes and knew this had been handled poorly.

I will share the other challenge for everyone's benefit later.  It was an equally interesting event a couple of months ago.

Tom

[wombat]

10 hours ago, Fly Boomer said:

In the low 20s (22,000 for example) your Time of Useful Consciousness (TUC) is 5 minutes.  That's for rapid decompression, which I assume would be similar to a sudden loss of oxygen.  That means, if you are average, you turn into a drooling idiot in 5 minutes after the event.  Probably will take at least a couple of minutes to notice that something is amiss.  You can't get down to good air fast enough.  A second (portable) bottle to back up the factory bottle is pretty cheap insurance.

https://en.wikipedia.org/wiki/Time_of_useful_consciousness

 

I am looking at buying a pulse oximeter with an alarm, which would help protect against my failure to continuously monitor the O2 saturation.   Humans are really bad at monitoring something that doesn't change much, and I'm no exception

Examples: 

https://www.turnermedical.com/CREATIVE_PC_60B1_FINGER_PULSE_OXIMETER_p/creative_pc-60b1.htm

https://www.concordhealthsupply.com/Wrist-Oximeter-p/75006.htm?gclid=CjwKCAjw6IiiBhAOEiwALNqncUt85iR167brcsAsyhAToxNDzKaX_JBpxzUmbxtC39iAliAH0O1pjRoCjeIQAvD_BwE&click=71&gad=1

 

If I am at FL220 and find that my oxygen is not working properly, it's an emergency.   I bet that with speed brakes on and engine to idle I can get down to lower altitudes pretty quick.   Hyperventilation is an option that can help for a short period of time.

[ilovecornfields]

2 hours ago, wombat said:

Hyperventilation is an option that can help for a short period of time.

One of my first Mooneyspace posts was on pulse oximeters and I basically got attacked for suggesting people get one and use it to adjust their oxygen delivery. I feel more used to the “feedback” now so I’ll comment again on things that have been said before:

1. Pulse oximeters are great, but to paraphrase Dirty Harry, you have to know their limitations.

2. They will read artificially high in the presence of CO.

3. They are inaccurate in the setting of poor perfusion (cold, poor circulation).

4. They tell you what happened in the past, not what’s happening now. This study showed it took almost a minute to detect acute hypoxemia in the foot (compared to ear) but a cold hand could easily have the same problem. 20-30s delay is not uncommon even in normal warm patients. https://pubmed.ncbi.nlm.nih.gov/10386281/

5. #4 is worse than it seems because the fall in oxygen levels once you start to get hypoxic isn’t linear. Once you detect hypoxemia on the pulse ox, you’re on a very steep part of the curve and likely much more hypoxic than the number is reading. If you factor in the time for the device to alarm, your response time (while hypoxic) to the alarm and the time it takes to take corrective action (while hypoxic) then it may be too late.

6. Hyperventilation doesn’t cure hypoxia. You’re just going to introduce another respiratory disorder (respiratory alkalosis) by blowing off CO2 and increase your chances of passing out.

7. Be careful out there.

CP thoughts only. Not a flight level flyer or flight surgeon.

Edit: Cool dog study showing how hyperventilation actually makes cerebral hypoxia worse (I guess not so cool if you were the dog).https://pubmed.ncbi.nlm.nih.gov/6774644/

[wombat]

Good post.  Those are all great points.

[Pinecone]

14 hours ago, Fly Boomer said:

In the low 20s (22,000 for example) your Time of Useful Consciousness (TUC) is 5 minutes.  That's for rapid decompression, which I assume would be similar to a sudden loss of oxygen.  That means, if you are average, you turn into a drooling idiot in 5 minutes after the event.  Probably will take at least a couple of minutes to notice that something is amiss.  You can't get down to good air fast enough.  A second (portable) bottle to back up the factory bottle is pretty cheap insurance.

https://en.wikipedia.org/wiki/Time_of_useful_consciousness

That is an average.  Some people are better and some worse.  I was good for over 5 minutes at 25,000 feet when I was younger.  I am not sure how long I could have gone, because they gave up and had me put my mask back on

Also, rapid decompression is NOT the same. When you rapid decompress, the air in your lungs expands and rushes out, taking what oxygen it had with it.

For ANYONE flying oxygen, I HIGHLY recommend a chamber ride to learn your personal hypoxia symptoms, as everyone is different.

[Raffi]

Thank you all for this very useful information!  At first it looked quite simple,  you put a mask on and there you go...

I got really valuable information on this subject, and I don't think I'm alone on this. 

Keep posting!