Supplemental oxygen

[2G]

The other day a couple of pilots were treating 123.3 as their private chat line which I was forced to listen to so I could hear my friend's hourly position reports. One of the things one kept (repeatedly) talking about was having to descend to 12,500 to "reset" the 30 minute clock. This is entirely wrong: there is no "resetting" of the clock; it is a ONCE A FLIGHT exception, no doubt intended to give pilots w/o supplemental oxygen leeway in crossing high-altitude mountain passes. The governing FAR is 91.211:

§ 91.211 Supplemental oxygen.
(a)General. No person may operate a civil aircraft of U.S. registry -

(1) At cabin pressure altitudes above 12,500 feet (MSL) up to and including 14,000 feet (MSL) unless the required minimum flight crew is provided with and uses supplemental oxygen for that part of the flight at those altitudes that is of more than 30 minutes duration;

(2) At cabin pressure altitudes above 14,000 feet (MSL) unless the required minimum flight crew is provided with and uses supplemental oxygen during the entire flight time at those altitudes; and

(3) At cabin pressure altitudes above 15,000 feet (MSL) unless each occupant of the aircraft is provided with supplemental oxygen.

[Charlie M. (UH & 002 owner/pilot)]

Great point.....
While never having to deal with this issue....my feeling (and FAA/NTSB if an incident or accident....), bouncing low for a short bit does NOT agree with Mother Nature.
While "maybe legal" (emphasis on MAYBE), Mother Nature is almost as a hard a judge as gravity (yeah....I know....no such thing as gravity.....the earth sucks.....you get the point....).

Sounds like this pilot may become a statistic....sucks for everyone else as well as family and friends.....:-(

[John DeRosa OHM Ω http://aviation.derosaweb.net]

I would have jumped on the party line and told them anonymously 1) please go to 123.5 and 2) BTW your thoughts on resetting the oxygen clock defies all medical knowledge and you are seriously risking hypoxia.

[[email protected]]

This was very helpful! I have had oxygen system crap out twice while flying over the Great Basin and bounced between 12,499 and 13,999 for the rest of the flight to get home. Good to know going below 12.5k doesn’t “reset� the 30 min timer.

Cheers!
Bruno - B4

[Tango Eight]

The smart guys are on O2 at >10,000 during the day and >5,000 at night. Most humans are measurably impaired at 12,500.

T8

[gkemp]

On Tuesday, July 23, 2019 at 8:57:52 AM UTC-7, Tango Eight wrote:
> The smart guys are on O2 at >10,000 during the day and >5,000 at night. Most humans are measurably impaired at 12,500.
>
> T8

The Air Force have done tests that show flight decision making can be negatively affected without supplemental Oxygen above 6000 feet. I always put mine on when I got into the cockpit when releasing above 6000 feet.

gkemp

[[email protected]]

O2 systems fail. Probably, the best thing you could do, would be go thru a altitude chamber course. Everyones symptoms are different and it is insidious while its happening. knowing your symptoms and when it(hypoxia) is happening to you, can be a life saver! I went threw a course at ASU a few years back. Recently while flying a friends glider in Moriarty, I noticed my symptoms gradually appearing (tingling o, the back of the neck and headache). This lead me to check the EDS system and realize it was not fuctioning properly. I was able to reset it and get it working so didnt abort but had I not recognized the problem------

CH

[John McCullagh[_2_]]

At 15:57 23 July 2019, Tango Eight wrote:
>The smart guys are on O2 at >10,000 during the day and >5,000 at night.
>Most humans are measurably impaired at 12,500.
>
>T8
>
Much depends on your age, fitness, smoking habits, medication such as
beta-blockers, length of flight and the altitude at which you normally
live. At 10,000ft, you need 30% oxygen to function as well as normal if you
live at sea-level. Since air is 21% oxygen: that is a 50% increase. Even
10,000 ft is too high without supplemental oxygen for many middle-aged
pilots who should be using a pulsed-demand supply soon after take-off for
high flights. The law is set in much the same way as blood/alcohol levels.
If you stay within legal limits, it does not mean that you are flying as
safely as you could. For example: visual sensitivity at night is decreased
by 10 percent at 5,000 ft and by 30 percent at 10,000 ft. Even in the day
at 10,000 ft there are reductions in memory capacity, patience, focus,
endurance etc. Jean-Marie Clement's book has 39 pages on the subject!

[Steve Koerner]

On a related note, if you run out of oxygen, you can get yourself some extra altitude margin in a pinch by pressure breathing. I rather discovered this while swimming laps. I could do better with a controlled pressurized exhale. I figured the same idea might transfer to soaring. I did some reading that supported the premise and then did some experimenting at altitude. It definitely works (legalities aside). Having 45 years of western soaring under my belt, I have a better than average sense for my own personal oxygen requirements. My tentative conclusion is that, for me, pressure breathing is worth around three thousand feet. Certainly I'm not recommending pressure breathing in lieu of supplemental oxygen, but it might be a useful thing to know about just in case.

[Charlie M. (UH & 002 owner/pilot)]

Agreed.....what is the cost of an O2 refill vs. a bad outcome?!?!??

Poor physical health, smoking (my bad....don't harp....I get enough already....), lack of sleep, different start point (coastal pilot suddenly flying at Denver or similar....) etc.
In general, I see no real downside to excess O2 other than sorta hyperventilating.....not great, but the opposite is way worse.
When you go O2 low, first thing to go is higher thinking.....exactly what you need then.....

No....have not done an altitude chamber....
No....have not done much flying above 10K'ASL.....
Yes, did a gold climb with no external O2 to about 13.5K' on the eastern seaboard.

[Eric Greenwell[_4_]]

Steve Koerner wrote on 7/23/2019 10:21 AM:
> On a related note, if you run out of oxygen, you can get yourself some extra altitude margin in a pinch by pressure breathing. I rather discovered this while swimming laps. I could do better with a controlled pressurized exhale. I figured the same idea might transfer to soaring. I did some reading that supported the premise and then did some experimenting at altitude. It definitely works (legalities aside). Having 45 years of western soaring under my belt, I have a better than average sense for my own personal oxygen requirements. My tentative conclusion is that, for me, pressure breathing is worth around three thousand feet. Certainly I'm not recommending pressure breathing in lieu of supplemental oxygen, but it might be a useful thing to know about just in case.
>
Are you talking about "pursed lips breathing"? That can raise my ox saturation 5
percentage points.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

[2G]

On Tuesday, July 23, 2019 at 10:23:55 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
> Agreed.....what is the cost of an O2 refill vs. a bad outcome?!?!??
>
> Poor physical health, smoking (my bad....don't harp....I get enough already....), lack of sleep, different start point (coastal pilot suddenly flying at Denver or similar....) etc.
> In general, I see no real downside to excess O2 other than sorta hyperventilating.....not great, but the opposite is way worse.
> When you go O2 low, first thing to go is higher thinking.....exactly what you need then.....
>
> No....have not done an altitude chamber....
> No....have not done much flying above 10K'ASL.....
> Yes, did a gold climb with no external O2 to about 13.5K' on the eastern seaboard.

Personally, I use a Mountain Pulse-Ox system that I set to come at 10,000 ft which you usually reach in a few minutes in the high desert. People, simply, should not bring gliders not equipped with O2 into this environment.

I took an altitude chamber ride to 25,000 ft, but that was 40 years ago. And half the day was spent in the classroom discussing physiological effects. Now they only take you to 18,000. All of the comments about physical degradation are, of course, valid and a wise pilot pays attention to them, especially drugs, dehydration and sleep quality. The basic problem with pushing the limits are the consequences of going past them. Remember, most accidents a series of factors that align malevolently, not just a single one.

Tom

[Eric Greenwell[_4_]]

Tango Eight wrote on 7/23/2019 8:57 AM:
> The smart guys are on O2 at >10,000 during the day and >5,000 at night. Most humans are measurably impaired at 12,500.

I might be even smarter: last year, I began using oxygen above 8000', when I
discovered I began a form of periodic breathing at about 8500'. It's easy to
detect with an oximeter, which showed my oxygen saturation varying between 95 and
90 over a 1 to 2 minute period. With my EDS turned on, I stay in the 96-97 range.

The periodic breathing is fairly common, I've read, among pilots and mountain
climbers. Another reason to carry and use an oximeter.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

[Glider1]

I have heard evidence that physical conditioning has a very low correlation with the tolerance of lower oxygen levels at altitude. This came from someone who regularly teaches classes in altitude oxygen deprivation and hypoxic conditions. He has done hundreds of demonstrations with class volunteers and says that other than regular smokers, asthma etc, everyone is different, no matter if you run 6 miles a day or sit in a chair playing video games eating Cheetos, makes no difference in predicting the altitude you will start going hypoxic.
As a result, I set the EDS at 5,000 feet.

[Steve Koerner]

On Tuesday, July 23, 2019 at 11:15:29 AM UTC-7, Eric Greenwell wrote:
> Steve Koerner wrote on 7/23/2019 10:21 AM:
> > On a related note, if you run out of oxygen, you can get yourself some extra altitude margin in a pinch by pressure breathing. I rather discovered this while swimming laps. I could do better with a controlled pressurized exhale. I figured the same idea might transfer to soaring. I did some reading that supported the premise and then did some experimenting at altitude.. It definitely works (legalities aside). Having 45 years of western soaring under my belt, I have a better than average sense for my own personal oxygen requirements. My tentative conclusion is that, for me, pressure breathing is worth around three thousand feet. Certainly I'm not recommending pressure breathing in lieu of supplemental oxygen, but it might be a useful thing to know about just in case.
> >
> Are you talking about "pursed lips breathing"? That can raise my ox saturation 5
> percentage points.
>
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> - "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm
>
> http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

Yes, Eric. Exhaling against pursed lips increases air pressure in your lungs during a substantial portion of the breathing cycle. Under some flying circumstances and terrain scenarios, doing so could well be a much better plan of action compared to opening the dive brakes if your oxygen fails or runs out.

[John Foster]

On Tuesday, July 23, 2019 at 1:28:42 PM UTC-6, Steve Koerner wrote:
> On Tuesday, July 23, 2019 at 11:15:29 AM UTC-7, Eric Greenwell wrote:
> > Steve Koerner wrote on 7/23/2019 10:21 AM:
> > > On a related note, if you run out of oxygen, you can get yourself some extra altitude margin in a pinch by pressure breathing. I rather discovered this while swimming laps. I could do better with a controlled pressurized exhale. I figured the same idea might transfer to soaring. I did some reading that supported the premise and then did some experimenting at altitude. It definitely works (legalities aside). Having 45 years of western soaring under my belt, I have a better than average sense for my own personal oxygen requirements. My tentative conclusion is that, for me, pressure breathing is worth around three thousand feet. Certainly I'm not recommending pressure breathing in lieu of supplemental oxygen, but it might be a useful thing to know about just in case.
> > >
> > Are you talking about "pursed lips breathing"? That can raise my ox saturation 5
> > percentage points.
> >
> > --
> > Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > - "A Guide to Self-Launching Sailplane Operation"
> > https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> > - "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm
> >
> > http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf
>
> Yes, Eric. Exhaling against pursed lips increases air pressure in your lungs during a substantial portion of the breathing cycle. Under some flying circumstances and terrain scenarios, doing so could well be a much better plan of action compared to opening the dive brakes if your oxygen fails or runs out.

It's called "PEEP". Positive End Expiratory Pressure. By blowing out through pursed lips, it increases the air pressure in the airways of the lungs, which is then transmitted to the alveoli (air sacks in the lungs). This increases the pressure that drives oxygen into the blood stream. Something to consider in an emergency, but don't rely on it regularly and don't use it to replace the regular use of supplemental oxygen at altitude.

[jfitch]

On Monday, July 22, 2019 at 8:50:36 AM UTC-7, 2G wrote:
> The other day a couple of pilots were treating 123.3 as their private chat line which I was forced to listen to so I could hear my friend's hourly position reports. One of the things one kept (repeatedly) talking about was having to descend to 12,500 to "reset" the 30 minute clock. This is entirely wrong: there is no "resetting" of the clock; it is a ONCE A FLIGHT exception, no doubt intended to give pilots w/o supplemental oxygen leeway in crossing high-altitude mountain passes. The governing FAR is 91.211:
>
> § 91.211 Supplemental oxygen.
> (a)General. No person may operate a civil aircraft of U.S. registry -
>
> (1) At cabin pressure altitudes above 12,500 feet (MSL) up to and including 14,000 feet (MSL) unless the required minimum flight crew is provided with and uses supplemental oxygen for that part of the flight at those altitudes that is of more than 30 minutes duration;
>
> (2) At cabin pressure altitudes above 14,000 feet (MSL) unless the required minimum flight crew is provided with and uses supplemental oxygen during the entire flight time at those altitudes; and
>
> (3) At cabin pressure altitudes above 15,000 feet (MSL) unless each occupant of the aircraft is provided with supplemental oxygen.

I turn my EDS on for 10,000 ft. But the wording in that regulation does not preclude several segments of flight between 12.5 and 14K. "that part of the flight at those altitudes" might include multiple segments. At the very least it is ambiguous. If you spend 1 minute at 12,501 then return to 12,499, surely you needn't land before bumping a second time to 12,501? Had it meant 30 minutes total, or only one continuous excursion, it would have been easy to write it that way.

[[email protected]]

I have been using, selling, installing and servicing oxygen systems for hang glider pilots and soaring pilots since 1991. My age is getting to be a factor, my field elevation is at 6,200 MSL (Moriarty, NM) with altitudes of 17,999 MSL on tap. I now set the MH EDS system to 5,000 and start huffing supplemental 02 about five minutes prior to launch. I have learned that it helps with my concentration on tow, especially during the turbulent and demanding midsummer conditions in the high desert. The amount of O2 used from 6,200 to release at around 8,000 and a climb to 10,000 is negligible.

[John DeRosa OHM Ω http://aviation.derosaweb.net]

On Tuesday, July 23, 2019 at 8:31:54 PM UTC-5, wrote:
> I have been using, selling, installing and servicing oxygen systems for hang glider pilots and soaring pilots since 1991. My age is getting to be a factor, my field elevation is at 6,200 MSL (Moriarty, NM) with altitudes of 17,999 MSL on tap. I now set the MH EDS system to 5,000 and start huffing supplemental 02 about five minutes prior to launch. I have learned that it helps with my concentration on tow, especially during the turbulent and demanding midsummer conditions in the high desert. The amount of O2 used from 6,200 to release at around 8,000 and a climb to 10,000 is negligible.

I'm with Mark Mocho on this. As a midwest flat-lander I start O2 out west as soon as I am in the glider (one less thing to forget after tow). My aged red blood chemistry is just not up to handling the thin air at the 5,000+ft airports that I fly out of. My MH EDS is always set to D5 and sometimes late in a flight I change to R/M for 5-10 minutes as a pick me up.

[[email protected]]

Everyone needs to read the August 2018 issue of Soaring magazine issue on hypoxia by Dr. Dan Johnson, Jean-Marie Clement, Patrick McLaughlin, & Dr. Heini Schaffner - the idea that anyone would not understand the effects of hypoxia and the cumulative effects of high altitude flying without O2 is scary and incredible. There is ample information available to anyone as to the folly of ignoring lower O2 levels. It will open your eyes as to the need to start O2 at lower altitudes regardless of age. Hypoxia is not an on/off physiological event - the effects are cumulative. And what one person can "get away with" does not mean another person can, or the same person can the next flight - the effects are individual. Incipient hypoxia stars at relatively low altitudes, and impairment at higher altitudes and/or prolonged exposure can be catastrophic. Listen to the recording cited in the August Soaring magazine issue "XC Tips" article by Garret Willat (now posted on the SSA website). PEEP or pursed lip breathing, as John F. points out, is a "now" expedient technique that will temporarily increase O2 levels. If you have to use it, and don't have supplemental O2, you must descend NOW while you still have the ability to do so. The basic recommendation from the Soaring magazine article is to start O2 at 5kft, regardless of fitness level, etc. The o2 is cheap compared to the alternative. And for those who regularly fly at high altitudes (>10 kft), of course you have a pulse oximeter along to periodically check your O2 saturation level.

[Ramy[_2_]]

I’ll confess. In the last 40 years I normally started my O2 above 12,500. I estimate I have something like 3-4000 hours between 5000-12500 without O2. I never felt a need to start any lower. I must be brain dead by now, which explains a lot ;)
But seriously, each individual is different. Not everyone needs O2 at 5000 feet, or even at 10,000 feet, and it does not make them irresponsible idiots if they don’t stick a cannula in their nose every flight at every altitude.
If I ever crash please don’t blame it on hypoxia.
Just wanted to offer a different perspective.

Ramy

[[email protected]]

Pilots who live at higher altitudes (Colorado, New Mexico) definitely have an advantage, as they are well acclimated to the thinner air. I remember seeing visitors from low-lying states gasping as they tried to carry their hang gliders on 12,200 ft. Gold Hill at Telluride, while those of us that were more used to it were hauling 100+ lbs. up the last stretch to launch with no significant problem. Of course, we were a lot younger then....

[Eric Greenwell[_4_]]

Ramy wrote on 7/24/2019 9:29 PM:
> I’ll confess. In the last 40 years I normally started my O2 above 12,500. I estimate I have something like 3-4000 hours between 5000-12500 without O2. I never felt a need to start any lower. I must be brain dead by now, which explains a lot ;)
> But seriously, each individual is different. Not everyone needs O2 at 5000 feet, or even at 10,000 feet, and it does not make them irresponsible idiots if they don’t stick a cannula in their nose every flight at every altitude.
> If I ever crash please don’t blame it on hypoxia.
> Just wanted to offer a different perspective.

....and that's why pilots should check their saturation with an oximeter even lower
than they would normally start using oxygen. People's responses do vary a lot.


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

[Dan Marotta]

I've got an oximeter in the Stemme but never used it in flight. I'll try
to remember to do that just to see the results.Â* I currently set my MH
regulator to 10K' but, given that I have my own O2 fill capability, it
wouldn't hurt much to lower that to 5K' just to see if I notice any
difference.

Oh, and I've attended USAF altitude chamber training twice while I was
in the AF and am familiar with my hypoxia symptoms.Â* I wonder if they
change with age...Â* And I've experienced a cabin pressure failure at
FL450.Â* Pressure breathing is not much fun!

On 7/25/2019 1:29 PM, Eric Greenwell wrote:
> Ramy wrote on 7/24/2019 9:29 PM:
>> I’ll confess. In the last 40 years I normally started my O2 above
>> 12,500. I estimate I have something like 3-4000 hours between
>> 5000-12500 without O2. I never felt a need to start any lower. I must
>> be brain dead by now, which explains a lot ;)
>> But seriously, each individual is different. Not everyone needs O2 at
>> 5000 feet, or even at 10,000 feet, and it does not make them
>> irresponsible idiots if they don’t stick a cannula in their nose
>> every flight at every altitude.
>> If I ever crash please don’t blame it on hypoxia.
>> Just wanted to offer a different perspective.
>
> ...and that's why pilots should check their saturation with an
> oximeter even lower than they would normally start using oxygen.
> People's responses do vary a lot.
>
>

--
Dan, 5J

[jfitch]

On Wednesday, July 24, 2019 at 8:59:56 PM UTC-7, wrote:
> Everyone needs to read the August 2018 issue of Soaring magazine issue on hypoxia by Dr. Dan Johnson, Jean-Marie Clement, Patrick McLaughlin, & Dr. Heini Schaffner - the idea that anyone would not understand the effects of hypoxia and the cumulative effects of high altitude flying without O2 is scary and incredible. There is ample information available to anyone as to the folly of ignoring lower O2 levels. It will open your eyes as to the need to start O2 at lower altitudes regardless of age. Hypoxia is not an on/off physiological event - the effects are cumulative. And what one person can "get away with" does not mean another person can, or the same person can the next flight - the effects are individual. Incipient hypoxia stars at relatively low altitudes, and impairment at higher altitudes and/or prolonged exposure can be catastrophic. Listen to the recording cited in the August Soaring magazine issue "XC Tips" article by Garret Willat (now posted on the SSA website). PEEP or pursed lip breathing, as John F. points out, is a "now" expedient technique that will temporarily increase O2 levels. If you have to use it, and don't have supplemental O2, you must descend NOW while you still have the ability to do so. The basic recommendation from the Soaring magazine article is to start O2 at 5kft, regardless of fitness level, etc. The o2 is cheap compared to the alternative. And for those who regularly fly at high altitudes (>10 kft), of course you have a pulse oximeter along to periodically check your O2 saturation level.

If I have to turn on the oxygen at 5K, I'm going to have to do it in the truck on the way up the hill to the airport. And keep it on the whole time I'm there. Airport is 6K and our takeoff is typically at 9000 ft density and can be 10K. 5K may make sense if you are a retiree living at 20 ft in Florida, but it lacks both practicality and necessity for everyone in every situation.

[[email protected]]

I will say it again - read the article in Soaring magazine - then comment. Opinions and anecdotes are fine, but I think we would rather bet our lives on actual data. The FAA "guidelines" were set circa WW II and were not based on physiological realities. The article explains the onset of hypoxia, and contains test results on a variety of individuals showing that the FAA regs are severely out of date as to onset altitude. Incipient hypoxia occurs at low altitudes (5-8kft), regardless of age and conditioning. Incipient does not mean disabling, but it is the start of (probably unnoticed by the individual) degradation of performance. The article does not address the question of whether individuals living at high altitudes (my house is at 6400 ft, but I turn on the O2 before taking off from Moriarty at 6200 ft) experience the onset of incipient hypoxia at higher altitudes. The article recommendation is on the side of ensuring sufficient O2 from start to finish of flight by those who have run and documented test results.

[Eric Greenwell[_4_]]

jfitch wrote on 7/25/2019 8:31 PM:
> On Wednesday, July 24, 2019 at 8:59:56 PM UTC-7, wrote:

>
> If I have to turn on the oxygen at 5K, I'm going to have to do it in the truck on the way up the hill to the airport. And keep it on the whole time I'm there. Airport is 6K and our takeoff is typically at 9000 ft density and can be 10K. 5K may make sense if you are a retiree living at 20 ft in Florida, but it lacks both practicality and necessity for everyone in every situation.
>
Don't worry about the density altitude, as your lungs respond to actual pressure,
unlike a carburetor.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

[Charlie Quebec]

I have a very large oxy bottle and always start oxygen at ground level. Ive noticed a reduction in fatigue and improved concentration.
5000ft might be OK, but I would rather spend a few bucks on oxy and be right at the top of my game all the time.

[6PK]

As someone already stated settings the MH to 5000msl uses negligible amounts of 02 even up to 10,000msl.
The cost is minimal and the benefit for some maybe huge....

[Dan Marotta]

I set my O2 to ground level yesterday and the density altitude was above
9,000' when I took off.Â* Still had a ho-hum flight.Â* At least it was
cool at 16,000' MSL.

On 7/29/2019 10:11 PM, Charlie Quebec wrote:
> I have a very large oxy bottle and always start oxygen at ground level. Ive noticed a reduction in fatigue and improved concentration.
> 5000ft might be OK, but I would rather spend a few bucks on oxy and be right at the top of my game all the time.

--
Dan, 5J