What is it like to use oxygen?

[ActiveTrader7]

I find it really weird that you have to use oxygen at high attitudes (obviously you need it). What is it like to strap-on a mask or nasal cannula? I can't imagine it would be comfortable. Why aren't airplanes that can cruise at high altitudes pressurized?

Are the Cirrus SR22 or Mooney Acclaim pressurized? Can you have the average plane retrofitted to become pressurized?

 

[mantakos]

Never used a mask, but as for a cannula, if you want to experience the wonders, stick your pinkies about a quarter inch up your nose. Now leave them there for the rest of the day.

It's a little bit annoying, but not really all that bad, is it?

Most "little" planes are capable of flying at altitudes at which the pilot is well-served by supplemental oxygen, though most flatlander pilots can do what they need to do without climbing that high.

The planes you mention are not pressurized. The reason they aren't all pressurized is because this is expensive, both to build and maintain. I've never heard of a plane that wasn't designed to be pressurized, being "retrofitted".

How many tens of thousands of dollars would you be willing to spend in order to not have to leave your pinkies in your nose for a few hours, now and then?
-harry

 

[Ken Ibold]

Pressurization adds weight, complexity and maintenance cost. Every hole through the pressure vessel has to be sealed. That means every cable and wire and screw and rivet has to be accounted for somehow. There are pressure bulkheads front and rear that add structure. The door seal has to be immaculate. Then there is the control mechanism and outflow valve, and the plumbing necessary to provide the pressurized air. Which is coming from where? Robbing power from the engine, perhaps?

At a time when the cost of airplanes is already going through the roof, the manufacturers are trying to come up with ways to keep the airplane light and cheap(er). The closest thing there is to a model that comes in pressurized/nonpressurized versions is the Piper Mirage/Matrix. There are differences other than pressurization (standard equipment such as boots, radar, copilot PFD), so a direct comparison is not possible, but the Mirage weighs 200 pounds more -- all of which comes out of payload -- and costs 50% more.

 

[Henning]

I find it really weird that you have to use oxygen at high attitudes (obviously you need it). What is it like to strap-on a mask or nasal cannula? I can't imagine it would be comfortable. Why aren't airplanes that can cruise at high altitudes pressurized?

Are the Cirrus SR22 or Mooney Acclaim pressurized? Can you have the average plane retrofitted to become pressurized?

Neither are exactly comfortable. Can you retrofit? No, not practicaly even if the airframe will take it. There's also the windows, door seals.... Consider this a low level of pressurization would be about 3.2 PSI, in your average 4 seat single that would equate to over 30,000 pounds of expansive force. That's a bomb.

If you're interested though, I have an idea to build an experimental single out of a P-Baron fuselage....

 

[ActiveTrader7]

Pressurization adds weight, complexity and maintenance cost. Every hole through the pressure vessel has to be sealed. That means every cable and wire and screw and rivet has to be accounted for somehow. There are pressure bulkheads front and rear that add structure. The door seal has to be immaculate. Then there is the control mechanism and outflow valve, and the plumbing necessary to provide the pressurized air. Which is coming from where? Robbing power from the engine, perhaps?

At a time when the cost of airplanes is already going through the roof, the manufacturers are trying to come up with ways to keep the airplane light and cheap(er). The closest thing there is to a model that comes in pressurized/nonpressurized versions is the Piper Mirage/Matrix. There are differences other than pressurization (standard equipment such as boots, radar, copilot PFD), so a direct comparison is not possible, but the Mirage weighs 200 pounds more -- all of which comes out of payload -- and costs 50% more.

and with the cost of the Mirage/Matrix, you can just by a light jet. If it came as an option on a new plane, I wouldn't mind paying extra. Sounds like to much work with an existing plane.

 

[SkyHog]

I use oxygen on a daily basis. Its kinda fun....lets me breathe!

 

[SteveinIndy]

I find it really weird that you have to use oxygen at high attitudes (obviously you need it). What is it like to strap-on a mask or nasal cannula? I can't imagine it would be comfortable. Why aren't airplanes that can cruise at high altitudes pressurized?

Are the Cirrus SR22 or Mooney Acclaim pressurized? Can you have the average plane retrofitted to become pressurized?

Because of what I have learned about them through my research (I do research into injury patterns in aircraft crashes) I wouldn't go up in a Cirrus if my life depended upon it (because it does), therefore I have no concern about the pressurization question. If I were you I would scratch it off your list of aircraft to consider. I have such serious concerns about their safety that when my CFI switched from a Cessa 182 to a Cirrus that I told her either we rented a different aircraft or I would find a new instructor.

 

[Dave Krall CFII]

Cannulas aren't bad at all when properly placed. The O2 is GREAT for relieving the often subtle fatigue of hypoxia at extended altitude flights and maintaining mental accuity. It makes me feel normal again, and that's not an easy thing to do!

 

[Henning]

and with the cost of the Mirage/Matrix, you can just by a light jet. If it came as an option on a new plane, I wouldn't mind paying extra. Sounds like to much work with an existing plane.

Even if you can buy a jet at close to the money, you'll never operate it even close, and I'm not even starting on insurance, just operating costs. If you want a small recip powered pressurized single, you basically have three options, one is experimental, the Lancair IVP (also available with a turbine) and two Certified, the Malibu and P-210. Outside of that you are looking at twin Recips, P-Barons, Aerostars, the 340, 414 &421 Cessnas (won't even think about the 411), the pressurized Navajos (again, I wouldn't consider them due to operating costs unless I had a job for them), a few pressurized Twin Commanders (these I like) and a few pressurized Queen Airs. When you get into the turbine powered aircraft, you options expand. Probably for a personal transport the TBM 850 come close to the top of my list (it has a slower less expensive sibling the TBM 700 as well) as a turbo prop single and another turbine single if you want a longer legged travelling machine with family or clients aboard, the Pilatus PC-12 is the front runner with it's larger cabin and lavatory facilities. When we start adding turbine twins to the mix, the Eclipse is out there as a jet, it is pressurized, but it most definitely is not cabin class, but for a jet, it is moderately priced, but again, the price of purchase is not indicative of the price of operation. As soon as you start getting into jets, costs make a steep climb curve. Even Turbo Props get pretty pricey, but when put alongside equivalent recips, it can be a competetive comparison especially when you calculate in dispatch reliability.

 

[Ted]

Most people seem to get by without oxygen just fine. The limits on when you need O2 (as I recall) are 12,500 ft for crew for a duration of longer than 30 minutes, 14,000 ft for crew so long as the duration of time above 12,500 is less than 30 minutes, and 15,000 for crew and PAX. If I'm wrong please correct me, since I should know this by now.

How often do you really expect to be up that high? Most of my friends, even on longer trips, don't usually go above 9,500. One of my friends got the Archer up to 10,500... that was a big deal. I know one person who flies a T182, and he'll go up until just below Class A with oxygen, and it doesn't seem to bug him any.

For you, I can't see much of a point in having a pressurized plane. There are a lot of extra systems and complexity associated with them. Certainly I have a dream of owning a P-Navajo... but that's a dream, and only if I didn't actually intend on flying it very much (or was very rich). Maintenance would be killer.

 

[TMetzinger]

Metzinger's Fifth Law Of Aviation:

For every aviation question that starts with "Why aren't", "Why don't", or "Why can't", the answer is always "Money."

 

[TMetzinger]

Most people seem to get by without oxygen just fine. The limits on when you need O2 (as I recall) are 12,500 ft for crew for a duration of longer than 30 minutes, 14,000 ft for crew so long as the duration of time above 12,500 is less than 30 minutes, and 15,000 for crew and PAX. If I'm wrong please correct me, since I should know this by now.

How often do you really expect to be up that high? Most of my friends, even on longer trips, don't usually go above 9,500. One of my friends got the Archer up to 10,500... that was a big deal. I know one person who flies a T182, and he'll go up until just below Class A with oxygen, and it doesn't seem to bug him any.

For you, I can't see much of a point in having a pressurized plane. There are a lot of extra systems and complexity associated with them. Certainly I have a dream of owning a P-Navajo... but that's a dream, and only if I didn't actually intend on flying it very much (or was very rich). Maintenance would be killer.

Your memory is correct. But what's "legal" and what's "safe" are two different things. I recommend using O2 for any flight above 10000 regardless of duration, and any flight above 6000 at night. Many folks who I respect recommend even lower altitudes. O2 makes a big difference in fatigue.

 

[SkyHog]

Your memory is correct. But what's "legal" and what's "safe" are two different things. I recommend using O2 for any flight above 10000 regardless of duration, and any flight above 6000 at night. Many folks who I respect recommend even lower altitudes. O2 makes a big difference in fatigue.

You must not respect me then, when I tell people (who hail from any elevation other than sea level) that the FAA's laws are actually overly protective, and that 12,500 ft is nothing, and 14,000 ain't much higher.

I use O2 when legally required, but I know that my body doesn't need it. I've been higher before without issue.

 

[SteveinIndy]

Metzinger's Fifth Law Of Aviation:

For every aviation question that starts with "Why aren't", "Why don't", or "Why can't", the answer is always "Money."

I am going to use this in an upcoming article.

 

[stingray]

If you are going to fly above 9000 it is a good idea to get a ox monitor for yourself. I did not know until I got one that I needed ox at 9000' or so if I was up for more than 1 hr. Everyone is different but they are so cheap it pays to have one aboard. I use a cannula it is not a bother for the value I get. (Not tired and no headache) when I land.

The P-210 would be a nice plane if you need a pressurized plane. Comes with KI so you get an all weather plane.

Dan

 

[Ken Ibold]

You must not respect me then, when I tell people (who hail from any elevation other than sea level) that the FAA's laws are actually overly protective, and that 12,500 ft is nothing, and 14,000 ain't much higher.

I use O2 when legally required, but I know that my body doesn't need it. I've been higher before without issue.

The thing to do is monitor your saturation level with a pulse oximeter. Below 90% and you ought to be on supplemental O2, regardless of your altitude. Everyone's body is different.

The old adage about legal does not equal safe and safe does not equal legal most definitely applies here.

 

[Ken Ibold]

Because of what I have learned about them through my research (I do research into injury patterns in aircraft crashes) I wouldn't go up in a Cirrus if my life depended upon it (because it does), therefore I have no concern about the pressurization question. If I were you I would scratch it off your list of aircraft to consider. I have such serious concerns about their safety that when my CFI switched from a Cessa 182 to a Cirrus that I told her either we rented a different aircraft or I would find a new instructor.

If that's the case, I have serious doubts about your methodology.

 

[Henning]

If that's the case, I have serious doubts about your methodology.

I wasn't even gonna touch that one, eeeesh.

 

[t0r0nad0]

Adam Z took it a step further...

http://www.pilotsofamerica.com/forum/showthread.php?p=266166#post266166

 

[SteveinIndy]

If that's the case, I have serious doubts about your methodology.

Why is that? I'm guessing you either sell or fly Cirrus aircraft? That is no grounds to immediately question the validity of my research nor to dig your heels in. The first tenet of research is to go where the data takes you, without regard for whatever your allegiances may or may not be. In my case, I simply wish to keep as low as possible the rate at which my fellow pilots are dying.

It's simply a fact that there seems so far to be a serious issue (or issues) with the aircraft produced by Cirrus. It may be a problem with the aircraft such as failure to include structural reinforcements or crashworthy fuel systems to make what otherwise would be a survivable crash a debacle in order to save weight, money, etc.

It may be the marketing of it to persons who should not be flying such an aircraft (seeing as how they are marketed as being a high performance aircraft compared
to similar GA designs) and instilling a false sense of security because of the Wile E. Coyote-esque ballistic recovery system. I use the cartoon analogy because if you read the accident reports for the aircraft with this system they normally deploy only AFTER impact.

Given the often cocky nature of pilots, those flying BRS-equipped aircraft may be more willing to get themselves into situations they have no business being in (VFR into IMC, etc). This is especially probably true in the case of low hour pilots.

Keep in mind that the information I am stating here is theory at this point, and based on preliminary analysis of our data. The formal publication should be ready for publication late this year or early next year. Regardless of that fact, I was simply stating my hesitance to fly in an aircraft that has issues- which have been questioned by persons far more eminent in the aviation community than myself.

 

[Ken Ibold]

Why is that? I'm guessing you either sell or fly Cirrus aircraft? That is no grounds to immediately question the validity of my research nor to dig your heels in...

I base my opinion on six years of aviation safety analysis covering every single general aviation accident in the United States, said period including the "early years" of the SR-22 when it seemed like one was crashing each week. I think most of the people on this board will vouch for my credentials as an aviation safety analyst. The NTSB did when it made me a panelist on the General Aviation Accident Prevention Symposium. The FAA did when they had me produce videos on aviation safety. Ditto EAA.

Trust me, I ain't digging my heels in. My conclusion then as now is that the accidents that are there cannot be traced to the AIRPLANE any more than they can be traced to the soft drinks the pilots packed on board.

 

[TMetzinger]

I'm with Ken - The Cirrus accident rate does not appear to indicate any design flaws in the airplane. Nearly all the cirrus accident reports I've looked at (a bunch) had causes related to pilot error.

So, for a passenger getting into an airplane with an unknown pilot, the risk may indeed be higher with a Cirrus. But that's not the same thing as saying the airplane is unsafe. Similar reputations have befallen other airplanes in their early years as well.

 

[SteveinIndy]

I base my opinion on six years of aviation safety analysis covering every single general aviation accident in the United States, said period including the "early years" of the SR-22 when it seemed like one was crashing each week. I think most of the people on this board will vouch for my credentials as an aviation safety analyst. The NTSB did when it made me a panelist on the General Aviation Accident Prevention Symposium. The FAA did when they had me produce videos on aviation safety. Ditto EAA.

Trust me, I ain't digging my heels in. My conclusion then as now is that the accidents that are there cannot be traced to the AIRPLANE any more than they can be traced to the soft drinks the pilots packed on board.

I am not necessarily blaming the crashes on the aircraft. I am talking about the survivability of the crashes that might happen for whatever reason. That is my focus of research, although the data on cause, etc is in my database and we're taking that into account.

I may PM you for your input on this and other issues if you don't mind.

 

[Henning]

Why is that? I'm guessing you either sell or fly Cirrus aircraft? That is no grounds to immediately question the validity of my research nor to dig your heels in. The first tenet of research is to go where the data takes you, without regard for whatever your allegiances may or may not be. In my case, I simply wish to keep as low as possible the rate at which my fellow pilots are dying.

It's simply a fact that there seems so far to be a serious issue (or issues) with the aircraft produced by Cirrus. It may be a problem with the aircraft such as failure to include structural reinforcements or crashworthy fuel systems to make what otherwise would be a survivable crash a debacle in order to save weight, money, etc.

It may be the marketing of it to persons who should not be flying such an aircraft (seeing as how they are marketed as being a high performance aircraft compared
to similar GA designs) and instilling a false sense of security because of the Wile E. Coyote-esque ballistic recovery system. I use the cartoon analogy because if you read the accident reports for the aircraft with this system they normally deploy only AFTER impact.

Given the often cocky nature of pilots, those flying BRS-equipped aircraft may be more willing to get themselves into situations they have no business being in (VFR into IMC, etc). This is especially probably true in the case of low hour pilots.

Keep in mind that the information I am stating here is theory at this point, and based on preliminary analysis of our data. The formal publication should be ready for publication late this year or early next year. Regardless of that fact, I was simply stating my hesitance to fly in an aircraft that has issues- which have been questioned by persons far more eminent in the aviation community than myself.

Well, that's what he was getting at, the methodology used in coming to your conclusion. You have just stated that you have used absolutely no methodology in coming to your conclusion, you have only collected accident statistics and applied your theory. On what do you base your theory that the Cirrus is less crashworth than any other aircraft in it's weight catagory? I have my own theories, and won't fly any composite construction aircraft that has been in a significant accident, but that comes about by my 2+ decades of working with composites and understanding their failure modes, on the other side of that coin though is that a properly designed composite structure is safer than a monocoque aluminum structure in the initial accident, however the aluminium I consider repairable where with the composite, I do not. Even safer to a point is a 4130 tube chassis plane, but once the critical energy barrier is breeched, the Composite structure is safer. Again, steel is repairable.

I have inspected and crawled through a Cirrus and looked over it's structural design work and would not hesitate to get in a new one, or one less than 6 years old. Before I bought one or flew an older one, I'd want to know a bit more about its layup schedule, I'd probably visit the factory and look at some raw parts and cross sections and observe some layup.

 

[SteveinIndy]

I'm with Ken - The Cirrus accident rate does not appear to indicate any design flaws in the airplane. Nearly all the cirrus accident reports I've looked at (a bunch) had causes related to pilot error.

So, for a passenger getting into an airplane with an unknown pilot, the risk may indeed be higher with a Cirrus. But that's not the same thing as saying the airplane is unsafe. Similar reputations have befallen other airplanes in their early years as well.

Of course, there's that famous quote about "When in doubt, blame the person who isn't around to defend himself..." but I am not going to go there since cause is not my area of focus.

 

[SteveinIndy]

Well, that's what he was getting at, the methodology used in coming to your conclusion. You have just stated that you have used absolutely no methodology in coming to your conclusion, you have only collected accident statistics and applied your theory.

Actually we are using logistic regression and other accepted statistical techniques to look at correlations. I actually had no theory when I started the project. I was actually surprised on the findings I have seen so far. The reason we are not publishing it yet is that we are seeking additional data prior to doing the final writeup that way we are not simply responding to some manner of aberration in the data.

If I find that is what I have based my preliminary assessment upon, I will gladly retract my statements here and would even fly in a Cirrus aircraft. Hell, I would even send a copy of the research to the president of Cirrus and tell him to feel free to use it in his marketing. If the evidence thus far holds true then, I will forward it to him and request that possible issues identified be addressed. In fact, I plan to do this for any manufacturer.

On what do you base your theory that the Cirrus is less crashworthy than any other aircraft in it's weight category?

Severity of injuries present in autopsy reports of accident victims that are coded according to establish standard measures of injury severity.

 

[poadeleted20]

I am not necessarily blaming the crashes on the aircraft. I am talking about the survivability of the crashes that might happen for whatever reason. That is my focus of research, although the data on cause, etc is in my database and we're taking that into account.

I'd really like to see your crashworthiness data. I have yet to see a Cirrus fatal accident which I, with 12 years experience as an aircraft survivability engineer, can imagine would have been survivable in any other airplane in its class.

 

[poadeleted20]

Severity of injuries present in autopsy reports of accident victims that are coded according to establish standard measures of injury severity.[emphasis added]

So you're comparing dead people with dead people? While this appears on its face to meet the "apples to apples" criterion, what difference does it make if one dead person's injuries are more severe than another's? They're both equally dead. What you need to find to convince me are cases of equally severe impacts in which the Cirrus occupants died but the non-Cirrus occupants survived. Absent that, we're only talking about how much work the undertaker has to do to make the corpse presentable, and I just can't see that as a basis for rejecting a fast, modern, comfortable, superbly equipped, highly ergonometric airplane like the Cirrus.

 

[Everskyward]

What is it like to strap-on a mask or nasal cannula? I can't imagine it would be comfortable. Why aren't airplanes that can cruise at high altitudes pressurized?

Back to the O2 mask question. I've used many different types of O2 masks for hours at a time. All I can say is they are not the most pleasant things in the world but you get used to it if necessary. Your passengers might not be so enamored of it though. The one problem I had with full face masks with built-in microphones is that after a while, moisture from breathing would sometimes cause the microphone to short out. I got around this by putting a small folded up tissue inside the mask to absorb the moisture. Also, if you are using a diluter-demand mask you need to remember to inhale strongly enough to activate the valve which supplies the O2.

The first time I flew a pressurized airplane it seemed weird that a mask was not necessary when climbing to altitude. Now I am totally spoiled and would not want to go back to using a mask on a regular basis.

I'm not even touching the Cirrus question.

 

[SteveinIndy]

So you're comparing dead people with dead people? While this appears on its face to meet the "apples to apples" criterion, what difference does it make if one dead person's injuries are more severe than another's? They're both equally dead. What you need to find to convince me are cases of equally severe impacts in which the Cirrus occupants died but the non-Cirrus occupants survived. Absent that, we're only talking about how much work the undertaker has to do to make the corpse presentable, and I just can't see that as a basis for rejecting a fast, modern, comfortable, superbly equipped, highly ergonometric airplane like the Cirrus.

The reason for using data from fatal cases is the lack of a large scale readily accessible source of data for survivors of plane crashes. One could conceivably use the National Trauma Data Bank but the number of applicable cases are low. This is one of those areas where the federal privacy laws are more of a hindrance than a help. If we identify that aircraft A has more of a problem with, for example, fire than aircraft B, then maybe there exists a problem with the system. The other use of fatal data is in seeing if injuries happen that could be an issue in aircraft egress (leg injuries, etc) leading to scene deaths, but not deaths upon impact such as due to thermal or inhalation injuries.

To avoid further derailing this thread any further, I suggest we take this discussion to private messages. My apologies to the OP....

 

[gprellwitz]

To avoid further derailing this thread any further, I suggest we take this discussion to private messages. My apologies to the OP....

I suggest moving it over to the thread Adam started a while back, because we may all have a chance to learn something.
http://www.pilotsofamerica.com/forum/showthread.php?p=266166#post266166

Moderators, would it be possible to move just the Cirrus-related posts over there?

And, as far as O2 goes, I've used a pulse oximiter and found that I do benefit from occasional hits of O2 when above even 8000'. The O2 sat goes up, and I feel a little more awake.

I don't particularly like the mask with the built-in mic because it's difficult to don and the sound quality isn't anywhere near as good.

And I'd like to know if there's benefit to using some of the supposed O2-saving canulas if you don't have the entire rig from the same company? In other words, can I plug the Aerox canula into the Cessna built-in O2 in the T182 or T210 and see a reduction in O2 usage?

 

[Henning]

And, as far as O2 goes, I've used a pulse oximiter and found that I do benefit from occasional hits of O2 when above even 8000'. The O2 sat goes up, and I feel a little more awake.

Conversly it can interupt a perfectly good nap...

And I'd like to know if there's benefit to using some of the supposed O2-saving canulas if you don't have the entire rig from the same company? In other words, can I plug the Aerox canula into the Cessna built-in O2 in the T182 or T210 and see a reduction in O2 usage?

Yes, basically all the systems (with the exception of the demand/diluter systems) are the same. The Aerox and other "saver" systems have a flow control in the hose between the pressure regulator and the mask. This is basically a needle and seat with a flowball to indicate how much O2 is flowing, typically they calibrate the scale in ft of altitude to match the the flow rate with altitude.

 

[TMetzinger]

Well, if nothing else, this conversation reminded me to go look at the date stamp on my portable O2 bottle. Date chiselled in the shoulder is 2000, but there's a stamp on it that says expires Jul 2009, so I guess my gas guy retested it when I got it filled in Jul 2004.

I find the cannulas comfy for long flights. The Aerox silicone mask was also comfy when I used it.

 

[gismo]

If you're interested though, I have an idea to build an experimental single out of a P-Baron fuselage....

You and several other folks. I even know of one flying example with a turbine bolted to a P-Baron airframe. Seems like I saw an online picture of something similar (I think the fuse was from a pressurized Aerostar) just yesterday. Personally, as much as I like my Baron, if I were to convert a pressurized piston twin to a turbine single, I'd start with something having a wider cabin and a much greater pressure differential than a P-Baron in which you need nose straws above FL180. I like the P-Baron too, for what it's intended, just doesn't seem like a good platform for this kind of modification.

 

[Henning]

You and several other folks. I even know of one flying example with a turbine bolted to a P-Baron airframe. Seems like I saw an online picture of something similar (I think the fuse was from a pressurized Aerostar) just yesterday. Personally, as much as I like my Baron, if I were to convert a pressurized piston twin to a turbine single, I'd start with something having a wider cabin and a much greater pressure differential than a P-Baron in which you need nose straws above FL180. I like the P-Baron too, for what it's intended, just doesn't seem like a good platform for this kind of modification.

I was going to use a GTSIO 520, probably K if I could find one, or a Chevy. The other consideration was converting the Mercedes or Audi Diesel. I dont think I'd tear up an Aerostar, though maybe a Duke....

 

[bbchien]

Because of what I have learned about them through my research (I do research into injury patterns in aircraft crashes) I wouldn't go up in a Cirrus if my life depended upon it (because it does), therefore I have no concern about the pressurization question. If I were you I would scratch it off your list of aircraft to consider. I have such serious concerns about their safety that when my CFI switched from a Cessa 182 to a Cirrus that I told her either we rented a different aircraft or I would find a new instructor.

I have made this comment in many locations and it never draws a reaction: "After a wreck there sure isn't much left of a Cirrus". Really, just a pile of melted composite. It even carries it's own autoignition source- and it has fired after impact quite a few times.

 

[SteveinIndy]

And I'd like to know if there's benefit to using some of the supposed O2-saving canulas if you don't have the entire rig from the same company?

My previous career (before I went back to school) was as a respiratory therapist and one thing you should keep in mind is that it's not a good idea mix and match oxygen devices, especially in the case of flow-sensing O2 setups. I do not know if this carries over to the aircraft O2 systems, but I would be hesitant to do so because of the potential negative consequences of a mismatch. Personally if it were me, and I were relying on bottled O2, I would invest in one of the newer carbon fiber tanks that are available through EMS suppliers. They carry a lot more O2 than a standard steel or aluminum tank for a lot of weight savings....approximately 1/2 to 1/3 the weight for a several fold increase in capacity. You could likely, at the flow rates associated with a cannula (2-6 L/min) get at least a couple of hours off of one using a standard nasal cannula.

The other issue, assuming you are talking about using the flow-sensing cannulae intended for home oxygen use (such as by COPD patients), is that I do not know if you can use them at altitudes above 5,000' AMSL. More correctly, I don't know if they have ever been tested for such environments. Just my two cents.....

 

[gismo]

Most people seem to get by without oxygen just fine. The limits on when you need O2 (as I recall) are 12,500 ft for crew for a duration of longer than 30 minutes, 14,000 ft for crew so long as the duration of time above 12,500 is less than 30 minutes, and 15,000 for crew and PAX. If I'm wrong please correct me, since I should know this by now.

How often do you really expect to be up that high? Most of my friends, even on longer trips, don't usually go above 9,500. One of my friends got the Archer up to 10,500... that was a big deal. I know one person who flies a T182, and he'll go up until just below Class A with oxygen, and it doesn't seem to bug him any.

For most folks the FAA part 91 O2 altitude limits are woefully inadequate. Yes you can stay conscious at and above 18,000 ft but your cognitive skills will be on the level of a lobotomized earthworm. BTW the regs are quite a bit more conservative when paying passengers are involved. I too have flown at 14,000 ft without O2 and I could tell that my thinking was mired in molasses. I've also found that spending more than 15 minutes above 10-11k MSL without O2 leaves me noticeably fatigued and often results in a headache. I've also found via a PulseOx meter that my O2 sat can be considerably different at the same altitude without O2 so just because you feel "OK" one one high flight doesn't mean you won't suffer more on another under the same environmental conditions.

 

[gismo]

And I'd like to know if there's benefit to using some of the supposed O2-saving canulas if you don't have the entire rig from the same company? In other words, can I plug the Aerox canula into the Cessna built-in O2 in the T182 or T210 and see a reduction in O2 usage?

A conserving canula will work with any continuous flow source that can supply a regular canula or mask, but to get the O2 savings you need to have an adjustable flow control and a flowmeter to set it. If you have all that and can set the flow to a level appropriate for your altitude it should work as well as if it were connected to a source "designed" for it. I still strongly recommend that you also use a blood oxygen saturation meter to confirm that you are getting enough oxygen though.

 

[Henning]

I have made this comment in many locations and it never draws a reaction: "After a wreck there sure isn't much left of a Cirrus". Really, just a pile of melted composite. It even carries it's own autoignition source- and it has fired after impact quite a few times.

Even if it doesn't burn, there still should be little left, it's part and parcel to the crash/failure mode of composites and is part of what saves your life. Metals crumple, but carbon fiber is different, it crushes and shatters. Carbon Fiber strands are a crystaline form bonded together by long strand polymer chains, typically epoxy or vinylester. It absorbs energy by shattering and dissintegrating rather than crumpling and folding. It is also one of the reasons I don't trust a pure carbon/plasic matrix that is older (fatigued, as there is no way to quantify the fatigue prior to failure) and/or has undergone a non deforming impact, because the crystaline chain can be shattered and disconnected while the the plastic it is imbedded in is undamaged due to its much higher modulous of elasticity (CF has a very low MF which is why it can provide such a rigid surface with such little material so you can make very light strong parts out of it). That's why many composite structures are truely composite and use Kevlar and S glass (and now a material I have been playing with lately that I'm pretty impressed with, polyethylene fibers). All materials are different and have different properties and failure modes. Their engineering is different, as is their failure analysis. Even different metals need to be analysed differently when reviewing their failures to see if they did what you wanted them to do.