Higher Altitudes and O2

[tundra_flier]

It still makes me wonder if pressurized ambient air without accompanying oxygen has been tried in flight, versus accompanying oxygen without pressurization.

You mean pressurized cockpit vs oxygen mask?  I was under the impression that a pressurized cockpit was the same as staying at a lower altitude physilogically.  Or did I missinterpret your question?

Phil

[Ted_Stryker]

It still makes me wonder if pressurized ambient air without accompanying oxygen has been tried in flight, versus accompanying oxygen without pressurization.

You mean pressurized cockpit vs oxygen mask?  I was under the impression that a pressurized cockpit was the same as staying at a lower altitude physilogically.  Or did I missinterpret your question?

Phil

A pressurized cockpit/cabin does eliminate the need for supplemental oxygen in that it is the same to the body physiologically.  The regs still state that pressurized or not, if you're over 14,000 you need to have it available.  On commercial aircraft it is not unusual to have at least one crewmember on O2, especially if one of the other crew leaves the cockpit.  This is a contingency procedure in case of a loss of pressurization, sudden or otherwise.

[Baradium]

I've read that staying below 10,000 ft is ideal without pressurisation.  I've also read an article by a female pilot who was flying over 8,000 who became disoriented.  Once she dipped below 8,000, things were back to normal.  I think it can depend on the person.

This makes me curious, though.  I wonder if a pressurized air machine would work differently than actual oxygen.  Of course, there's the military, who use pressurized oxygen in their masks.  They have the best of both.

My mother has been a respiratory therapist for as long as I know, so her speculations would probably put my guesses to shame.  It still makes me wonder if pressurized ambient air without accompanying oxygen has been tried in flight, versus accompanying oxygen without pressurization.

I've been working in the medical field for 2 years, so I know enough to really do some damage.   

When you fly in an airliner, it's pressurized ambient air in the cabin.

-Ryan

[Baradium]

A pressurized cockpit/cabin does eliminate the need for supplemental oxygen in that it is the same to the body physiologically.  The regs still state that pressurized or not, if you're over 14,000 you need to have it available.  On commercial aircraft it is not unusual to have at least one crewmember on O2, especially if one of the other crew leaves the cockpit.  This is a contingency procedure in case of a loss of pressurization, sudden or otherwise.

This might have been misleading...  oxygen availible is determined by cabin pressure altitudes.  Emergency oxygen systems under a different category are determined by the amount of time to get to an altitude that doesn't require oxygen IIRC.

For example, we have to offer oxygen to passengers if our cabin pressure is above xxx altitude, but we don't if we are above that altitude and our cabin pressure altitude stays low.

By availible I take it to mean the FAA definition that a passenger can use it if they want, not that it has to be around for the crew to deploy (such as our emergency oxygen systems).

[Ted_Stryker]

A pressurized cockpit/cabin does eliminate the need for supplemental oxygen in that it is the same to the body physiologically.  The regs still state that pressurized or not, if you're over 14,000 you need to have it available.  On commercial aircraft it is not unusual to have at least one crewmember on O2, especially if one of the other crew leaves the cockpit.  This is a contingency procedure in case of a loss of pressurization, sudden or otherwise.

This might have been misleading...  oxygen availible is determined by cabin pressure altitudes.  Emergency oxygen systems under a different category are determined by the amount of time to get to an altitude that doesn't require oxygen IIRC.

For example, we have to offer oxygen to passengers if our cabin pressure is above xxx altitude, but we don't if we are above that altitude and our cabin pressure altitude stays low.

By availible I take it to mean the FAA definition that a passenger can use it if they want, not that it has to be around for the crew to deploy (such as our emergency oxygen systems).

Well said.... and correct.  Thanks for clarifying.   I did indeed, unintentionally, mix the requirements for emergency crew oxygen vice passenger O2 in my post.  Sorry about any confusion my statement may have caused.       That's what I get for posting before having had sufficient coffee   

[fireflyr]

A pressurized cockpit/cabin does eliminate the need for supplemental oxygen in that it is the same to the body physiologically.  The regs still state that pressurized or not, if you're over 14,000 you need to have it available.  On commercial aircraft it is not unusual to have at least one crewmember on O2, especially if one of the other crew leaves the cockpit.  This is a contingency procedure in case of a loss of pressurization, sudden or otherwise.

This might have been misleading...  oxygen availible is determined by cabin pressure altitudes.  Emergency oxygen systems under a different category are determined by the amount of time to get to an altitude that doesn't require oxygen IIRC.

For example, we have to offer oxygen to passengers if our cabin pressure is above xxx altitude, but we don't if we are above that altitude and our cabin pressure altitude stays low.

By availible I take it to mean the FAA definition that a passenger can use it if they want, not that it has to be around for the crew to deploy (such as our emergency oxygen systems).

Well said.... and correct.  Thanks for clarifying.   I did indeed, unintentionally, mix the requirements for emergency crew oxygen vice passenger O2 in my post.  Sorry about any confusion my statement may have caused.       That's what I get for posting before having had sufficient coffee   

Don't you have an IV stand for caffiene next to your desk???

[Baradium]

Well said.... and correct.  Thanks for clarifying.   I did indeed, unintentionally, mix the requirements for emergency crew oxygen vice passenger O2 in my post.  Sorry about any confusion my statement may have caused.       That's what I get for posting before having had sufficient coffee   

I figured it was unintentional.  I could tell what you meant, but wasn't sure if it was obvious for those who don't deal with oxygen requirements on a regular basis.   


I havn't had any coffee today, but I try to just not take caffiene period.  I'm actually supposed to be at the airport, but as I was walking out the door company called and said to relax because there isn't an airplane for me.  At least they're being nice and not paying me for sitting at home instead of not paying me for sitting at the airport all day.   

[Ted_Stryker]

A pressurized cockpit/cabin does eliminate the need for supplemental oxygen in that it is the same to the body physiologically.  The regs still state that pressurized or not, if you're over 14,000 you need to have it available.  On commercial aircraft it is not unusual to have at least one crewmember on O2, especially if one of the other crew leaves the cockpit.  This is a contingency procedure in case of a loss of pressurization, sudden or otherwise.

This might have been misleading...  oxygen availible is determined by cabin pressure altitudes.  Emergency oxygen systems under a different category are determined by the amount of time to get to an altitude that doesn't require oxygen IIRC.

For example, we have to offer oxygen to passengers if our cabin pressure is above xxx altitude, but we don't if we are above that altitude and our cabin pressure altitude stays low.

By availible I take it to mean the FAA definition that a passenger can use it if they want, not that it has to be around for the crew to deploy (such as our emergency oxygen systems).

Well said.... and correct.  Thanks for clarifying.   I did indeed, unintentionally, mix the requirements for emergency crew oxygen vice passenger O2 in my post.  Sorry about any confusion my statement may have caused.       That's what I get for posting before having had sufficient coffee   

Don't you have an IV stand for caffiene next to your desk???

Hmm... IV stand at the desk.....  GREAT IDEA!!!    I'll have to work on that          Yesterday I went through almost two full pots of coffee before I went home and had another.  Am I addicted to coffee?  Nah... I can live without it.  I can go days without a sip... but if it's available...    I think it's more like that great quote from Ensign Pavel Chekov in the Star Trek episode "The Deadly Years".  At one point Chekov is complaining about all the medical samples McCoy is taking and Sulu says "You'll live."   Checkov's prompt retort is; "Oh yes, I'll live.   But I won't enjoy it!"      

[Ted_Stryker]

Well said.... and correct.  Thanks for clarifying.   I did indeed, unintentionally, mix the requirements for emergency crew oxygen vice passenger O2 in my post.  Sorry about any confusion my statement may have caused.       That's what I get for posting before having had sufficient coffee   

I figured it was unintentional.  I could tell what you meant, but wasn't sure if it was obvious for those who don't deal with oxygen requirements on a regular basis.   


I havn't had any coffee today, but I try to just not take caffiene period.  I'm actually supposed to be at the airport, but as I was walking out the door company called and said to relax because there isn't an airplane for me.  At least they're being nice and not paying me for sitting at home instead of not paying me for sitting at the airport all day.   

Well, glad they called you in enough time!  I may be able to pop on the chat interface sometime in the next couple of hours.  We could echange notes about flying experiences

[Baradium]

Well, glad they called you in enough time!  I may be able to pop on the chat interface sometime in the next couple of hours.  We could echange notes about flying experiences

Sounds good, I'll be in chat as long as they don't call me in.

[tundra_flier]

At least they're being nice and not paying me for sitting at home instead of not paying me for sitting at the airport all day.   

Hmmmm...the airport is my favorite place to waste time. 

Phil

[YawningMan]

Oh, hehe.  Yes, pressurized cabins are definitely pressurized ambient air, but that's not what I had meant.

My curiosity was for aircraft that can make it to those altitudes that might not have a pressurized cabin.  Let me try again.

I work as a sleep lab technician.  Most of the time, I am treating Sleep Apnea.  For patients who have sleep apnea, they are prescribed a mask that fits over the nose, or the nose and the mouth.  This creates pressurized ambient air in the nasal passages, or nasal and oral passages locally on the person.  The rest of the body doesn't experience any kind of pressurized air.

What I was thinking is how useful it would be to develop a similar system as a way to provide an air supply to a pilot in flight who might not have a pressurized cabin, and might not have an easy time of finding a supplier of compressed O2, or would rather pay a higher cost upfront than have to always pay for the service to recharge his O2 tank.

As I think about it more and more, I'm beginning to doubt it's viability as a replacement for O2 for pilots.  O2 can be delivered via a simple cannula.  The pressurized air is delivered via a mask, or at best, by bigger tubing that fits in the nasal passages, called "Nasal pillows".  While you wouldn't have to recharge your O2 canister, you would likely have to recharge a battery.  This battery would likely have to be somewhat bulky to carry sufficient charge over a sustainable amount of time.  Weight would likely be at least as much as an O2 canister, if not heavier.

Getting back to the mask, this could be problematic.  I know pilots without perfect vision who opt out of wearing glasses because of limited visibility where the frames of the glasses lie in their field of view.  The mask does sit somewhat in front of the eyes.  Nasal Pillows don't, but I'm about to touch on the disadvantage with those.

Nasal masks or pillows might create a problem with communications.  The pilot's microphone normally sits immediately in front of their lips.  Everytime I've seen a pilot with a headset, that's where the microphone has been.  With pressurized air in the nasal passageway, that means there will be a gust of air each time the pilot opens his mouth to speak into the microphone, and it could create unwanted interference, unless there was a dampener on the microphone.  Still, if someone isn't used to the mask, it is unusual to try and speak with air rushing out of one's mouth.

Further considerations are the effects of the pressure on a person's ears.  This is especially important in flight, and at higher altitudes.  It could cause more problems than it fixes.

I guess I answered my own question.   

[Baradium]

At least they're being nice and not paying me for sitting at home instead of not paying me for sitting at the airport all day.   

Hmmmm...the airport is my favorite place to waste time. 

Phil

Haha!  I enjoy that too, but it's not so fun when you have to sit on a couch next to dispatch and *can't* go anywhere. 

[Baradium]

As I think about it more and more, I'm beginning to doubt it's viability as a replacement for O2 for pilots.  O2 can be delivered via a simple cannula.  The pressurized air is delivered via a mask, or at best, by bigger tubing that fits in the nasal passages, called "Nasal pillows".  While you wouldn't have to recharge your O2 canister, you would likely have to recharge a battery.  This battery would likely have to be somewhat bulky to carry sufficient charge over a sustainable amount of time.  Weight would likely be at least as much as an O2 canister, if not heavier.

For it to work you'd have to be able to maintain the higher pressure of air in the lungs, which would make it hard to breathe in and out.  It couldn't just be forced in, it'd have to pressurize the lungs themselves because the problem with altitude is the lower pressure making it harder to absorb oxygen.

The thing about pure oxygen (or diluted oxygen per a diluter demand mask), is that you get the same or more oxygen into the body with the lower pressure in the lungs because of the higher % of oxygen now in the air.  Inserting a tube into your mouth wouldn't work because you would still end up with ambient pressure in your lungs.   A pressurized air system would have to be sealed around your face and even then I would think it'd be hard on the body.

[tundra_flier]

Nasal masks or pillows might create a problem with communications.  The pilot's microphone normally sits immediately in front of their lips.  Everytime I've seen a pilot with a headset, that's where the microphone has been.  With pressurized air in the nasal passageway, that means there will be a gust of air each time the pilot opens his mouth to speak into the microphone, and it could create unwanted interference, unless there was a dampener on the microphone.  Still, if someone isn't used to the mask, it is unusual to try and speak with air rushing out of one's mouth.

Communications wouldn't really be a problem, you'd just have to use a throat mic.  They're used with many hands free phone systems, and were used by WWII bomber crews because of the oxygen mask.  I am curious how that would work with the ear drums though.  With higher pressure in the respiritory tract than ambient.  I'd think it'd be like doing a fast decent, except you couldn't pop your ears.   

Phil