Mooney down in Atlantic

[cnoe]

These minimum standards then become the training goals of 98% of the students out there. Think about it, their personal goal is to achieve the minimum required standards. It seems pretty foolish when you think about it doesn't it? Then, just as soon as those minimum standards are met, most pilots stop their training, take their checkride and hope to live happily ever after.

Without trying to be disrespectful I have to wonder what group of pilots you're hanging out with. Your statements above seem to ignore the MANY pilots I encounter regularly attending safety meetings, seminars, training courses, etc. There's been a tremendous effort by local and distant participants to develop and train Formation Flying groups across the country with one of the BEST right here in Texas. If I'm not mistaken the Mooney Summit sold out again this year. And don't forget that the very subject of this thread was enroute to attend a Mooney PPP.

I for one am always seeking more knowledge and experience, and I suspect that there are many many more like me. There are certainly pilots who are slackers, but hopefully not in the numbers you imply.

Keep training for sure, after all it's only a license to learn.

Cnoe

Sent from my iPad using Tapatalk

[carl]

Pulse oximeters are dangerous.

They are great for showing trends in a hospital environment, but have no place in an aircraft.

Pulse oximeters are worn on the extremities; because of this location they present a lag between central oxygenation, cerebral oxygenation and peripheral oxygenation.

This lag may be upwards of 2 minutes. This depends on several factors such as cardiac output, muscle movement and ambient temperature.

So, what you are seeing has already happened, it is in the past.

Go on, you are in your kitchen; put your pulse-ox on.  Walk around and breathe, look at your reading, 98%. Now hold your breath. Time how long it takes to get to 90% (a moderate level of hypoxia approximating an oxygen pressure in the blood of 60 torr). I bet you can’t hold your breath that long. Why? Because as you are holding your breath the oxygen level in the blood drops fast. It is felt first in the brain. But because you are checking it at the periphery, deoxygenated blood will get to that location in the longest amount of time. Oh yes and you were walking around right.

Try it again after sitting for a while in one spot, sit on a couch for thirty minutes and repeat the test. Hold your breath until you reach a sat of 90%. It will take longer for the extremities to be perfused. Your brain will be hypoxic much sooner.

Now don’t try this again at the flight levels, where it might be a bit cooler, blood has pooled in the extremities.

Remember get your sat monitor up to 98% to start.

Remove your oxygen; your cerebral oxygenation will tend toward zero within one minute, one cardiac volume cycle. The only reason it doesn’t go there immediately is due to stagnant oxygenated blood being circulated, your oxygen to your brain is coming from your fingers, not from your lungs.

Now glance at you pulse-ox as you start to black out. What does it read? 98% give it a couple of minutes to adjust. Out of time.

Pressurized cabins have a cushion, even when they fail, they leak and the pressure does not go immediately to outside pressure, giving the crew (two pilots) time to put on their masks.

With unpressurized cabins you are already breathing outside the plane. And there is really nothing outside to breath.

25,000 feet  pB =282.4 mmHg

PAO2 = 21%(282.4-47 ) – (40)(1.25)

PAO@ = -0.566

[gsxrpilot]

Yeah, I think I can hear what Ward's trying to say, but I gotta agree with Chuck. Most all the pilots I've ever met LOVE to learn. In fact, I would make the gross generalization the OTHER way. People who don't like to learn, who can't "stick with it" and learn the hard things... never become pilots. None of us had to become pilots to fly. I sit next to people several times a week on Southwest or United who are very happy to let someone else figure out the flying stuff and let them just sit there and have another drink. But we all took a flight and said to ourselves, I gotta LEARN how to do that!

This is obviously a very unfortunate accident. And I sincerely hope we learn exactly what happened and what caused it. Obviously the pilot was comfortable flying in the flight levels and had done it many times as evidenced on FlightAware. It's dangerous, but he was comfortable with the risk. It's dangerous to fly single engine IFR, it's dangerous to fly single engine at night.  Hell, it's dangerous to get in our little Mooney's and go fly period. But we all accept the risk.

This has been a great discussion of what needs to be done and considered when flying at altitude. And I appreciate it even though I fly a C and I'm pretty sure my best defense against hypoxia is the 180hp fan up front. But I'm not going to even consider that the pilot was being reckless, foolish, or complacent. If I go down that path, it's time for me to sell the plane.

[carusoam]

Carl,

help me understand something, if you would...

i have a fancy pulse-ox.  I kind of know that it is working because it is graphing the pulsation that it sees.  Then it gives my heart rate and it's best estimate of oxygen concentration in my blood.

if I have an oxygen problem, it displays a low number with an elevated heart rate.

it confirms what I am seeing, blurred vision, and what I'm feeling, elevated HR.  It explains the additional deep breaths I'm taking.

it works as a digital reminder to increase or check my O2 system.

isn't the 'no place in an aircraft' a bit strong?  

What else do I have to rely on that is better?

two minute old data is pretty good at 12k', unless we are at 25k' where two minutes just isn't...

back to the re-design of O2 systems and their operations for that harsh of an environment.

best regards,

-a-

 

 

 

 

Edited September 18, 2015 by carusoam

[WardHolbrook]

 

Without trying to be disrespectful I have to wonder what group of pilots you're hanging out with. Your statements above seem to ignore the MANY pilots I encounter regularly attending safety meetings, seminars, training courses, etc.

 

Just a personal observation from over 35 years as a CFI, 40 years flying for a living and 49 years as a licensed pilot. I realize that I am most likely preaching to the choir here, but there are more than a few out there who aren't "proactive" when it comes to training and proficiency. I'm sure we all know plenty of guys (and probably a few here) whose only recurrent training events consists of a BFR.

The guys I hang around with get sim training every 6 to 12 months in addition to other periodic training events such as aerobatic training, high altitude physiology training (altitude chamber) and attend frequent safety meetings, seminars, and other training courses. The guys you read about in the accident reports usually aren't the ones that you see attending the meetings, seminars, training courses, etc. The guys you see participating in those are a fraction of the total pilot population. Just saying. 

[cnoe]

I do appreciate your observations. As a late bloomer I'll never reach the level of experience attained by many on this forum but I'm doing my best to learn all I can along the way. I'm just glad to be hanging around many active pilots and perpetual students of flight.

 

I am encouraged by what appears to be a trend of significant decline in serious/fatal GA accidents. "Something" is apparently improving flight safety, but alas the world still remains an imperfect place.

 

 

Sent from my iPad using Tapatalk

Edited September 18, 2015 by cnoe

[DXB]

Pulse oximeters are dangerous.

 

They are great for showing trends in a hospital environment, but have no place in an aircraft.

 

Pulse oximeters are worn on the extremities; because of this location they present a lag between central oxygenation, cerebral oxygenation and peripheral oxygenation.

 

This lag may be upwards of 2 minutes. This depends on several factors such as cardiac output, muscle movement and ambient temperature.

 

So, what you are seeing has already happened, it is in the past.

 

Go on, you are in your kitchen; put your pulse-ox on.  Walk around and breathe, look at your reading, 98%. Now hold your breath. Time how long it takes to get to 90% (a moderate level of hypoxia approximating an oxygen pressure in the blood of 60 torr). I bet you can’t hold your breath that long. Why? Because as you are holding your breath the oxygen level in the blood drops fast. It is felt first in the brain. But because you are checking it at the periphery, deoxygenated blood will get to that location in the longest amount of time. Oh yes and you were walking around right.

 

Try it again after sitting for a while in one spot, sit on a couch for thirty minutes and repeat the test. Hold your breath until you reach a sat of 90%. It will take longer for the extremities to be perfused. Your brain will be hypoxic much sooner.

 

Now don’t try this again at the flight levels, where it might be a bit cooler, blood has pooled in the extremities.

 

Remember get your sat monitor up to 98% to start.

 

Remove your oxygen; your cerebral oxygenation will tend toward zero within one minute, one cardiac volume cycle. The only reason it doesn’t go there immediately is due to stagnant oxygenated blood being circulated, your oxygen to your brain is coming from your fingers, not from your lungs.

 

Now glance at you pulse-ox as you start to black out. What does it read? 98% give it a couple of minutes to adjust. Out of time.

 

Pressurized cabins have a cushion, even when they fail, they leak and the pressure does not go immediately to outside pressure, giving the crew (two pilots) time to put on their masks.

 

With unpressurized cabins you are already breathing outside the plane. And there is really nothing outside to breath.

 

25,000 feet  pB =282.4 mmHg

 

PAO2 = 21%(282.4-47 ) – (40)(1.25)

 

PAO@ = -0.566

 

You are partly correct on the physiologic principle and point out a limitation of sat monitors- that with a sudden dramatic decrease in pO2 in the lung alveolus  (PAO2), pO2 in cerebral tissues always drops ahead of SaO2 in the capillaries of your finger where it is being measured. However you misuse the alveolar gas equation, which is not a valid estimate of PAO2 at high altitude -  a PAO2 < 0 is simply not possible.  And a PAO2 of near 0 is not compatible with life - yet a lot of sherpas and climbers manage ok without O2. I'm hardly an expert here, but this seems like a good write-up on limitations of the equation, including what actual empiric PAO2s are at altitude:   http://ceaccp.oxfordjournals.org/content/4/1/24.full

More importantly, I disagree with the conclusion that sat monitors are dangerous and have no place in an aircraft. I do suspect they will be pretty useless in a sudden decompression at FL430.  But if your O2 flow stops working at 17,000, no healthy person is going to pass out quickly. Yet one might feel sick or do something stupid. If you feel funny, you can get accurate SaO2 feedback within a minute or two that tells you that you should come down immediately.  At FL250, useful consciousness without prior acclimation is much shorter, but there is quite a bit of variability from person to person, and a guy who lives in Breckenridge will do much better than me. If your O2 is not working during your climb to this altitude or forgot to turn it on, you can certainly get some warning from a sat monitor.  If you are using an inadequate O2 flow or the flow gradually drops unnoticed at FL250, the SaO2 monitor can also warn you.  At relatively low altitudes (5,000-12,500), there is also tremendous variability in the amount SaO2 drops from person to person, and a monitor can help guide O2 use in this lower risk setting, particularly at night.  I also wouldn't hesitate to use a monitor to tune my O2 flow rate at 12,500-17,000.  I say use a monitor early and often in these settings.   I think they are much more likely to cause anxiety and confusion from false low readings or not picking up a reading than give false assurance from normal readings.

Lastly, in a hospital environment the monitors are certainly not merely useful for general trend monitoring.  They are useful for moment to moment life saving decision making on patients because changes in systemic O2 delivery are reflected in a very short time. Yes they lag behind cerebral pO2, but that knowledge is built into our interpretation. There is no reason I see they can't be used on one's self for the same purpose in an aircraft, albeit without complacency- it won't save you every time at higher altitudes if you are already too impaired to act on the low number.  

 

[ArtVandelay]

Pulse oximeters are dangerous.

They are great for showing trends in a hospital environment, but have no place in an aircraft.

Pulse oximeters are worn on the extremities; because of this location they present a lag between central oxygenation, cerebral oxygenation and peripheral oxygenation.

This lag may be upwards of 2 minutes. This depends on several factors such as cardiac output, muscle movement and ambient temperature.

So, what you are seeing has already happened, it is in the past.

Go on, you are in your kitchen; put your pulse-ox on.  Walk around and breathe, look at your reading, 98%. Now hold your breath. Time how long it takes to get to 90% (a moderate level of hypoxia approximating an oxygen pressure in the blood of 60 torr). I bet you can’t hold your breath that long. Why? Because as you are holding your breath the oxygen level in the blood drops fast. It is felt first in the brain. But because you are checking it at the periphery, deoxygenated blood will get to that location in the longest amount of time. Oh yes and you were walking around right.

Try it again after sitting for a while in one spot, sit on a couch for thirty minutes and repeat the test. Hold your breath until you reach a sat of 90%. It will take longer for the extremities to be perfused. Your brain will be hypoxic much sooner.

Now don’t try this again at the flight levels, where it might be a bit cooler, blood has pooled in the extremities.

Remember get your sat monitor up to 98% to start.

Remove your oxygen; your cerebral oxygenation will tend toward zero within one minute, one cardiac volume cycle. The only reason it doesn’t go there immediately is due to stagnant oxygenated blood being circulated, your oxygen to your brain is coming from your fingers, not from your lungs.

Now glance at you pulse-ox as you start to black out. What does it read? 98% give it a couple of minutes to adjust. Out of time.

Pressurized cabins have a cushion, even when they fail, they leak and the pressure does not go immediately to outside pressure, giving the crew (two pilots) time to put on their masks.

With unpressurized cabins you are already breathing outside the plane. And there is really nothing outside to breath.

25,000 feet  pB =282.4 mmHg

PAO2 = 21%(282.4-47 ) – (40)(1.25)

PAO@ = -0.566

This "test" is not valid. The problem with holding your breath is that CO2 levels increase the bloodstream, which causes its own problems, this is why you can't just put a bag over your mouth and become hypoxic. I have tested one of those small O2 canisters that give you 30 breaths, my O2 levels go from 90 to 97 with 2 breaths, that's only 20-30 seconds between readings.

For a person at rest, it's takes about 1 minute for blood to make the round trip through the body, so the blood at the finger is half way on its trip, 30 seconds, as you become hypoxic your heart rate increases, so drop that some more. Of course these are averages, and depends on you fitness level, age, weight, etc.

Obviously if you lose O2 at 25000' or higher, waiting that long it too much. This is why you should have an airflow indicator on each persons air hose and a air pressure gauge as well, which should be checked as part of your preflight. The airflow indicator should be part of your scan, it will give you an instantaneous indication if airflow has stopped.

Having a couple of the small O2 cans in your flight bag could provide O2 long enough to get to lower altitude, they are cheap insurance, just make sure they aren't made in China.

[Deb]

Pulse oximeters are dangerous.

 

They are great for showing trends in a hospital environment, but have no place in an aircraft.

 

Pulse oximeters are worn on the extremities; because of this location they present a lag between central oxygenation, cerebral oxygenation and peripheral oxygenation.

 

This lag may be upwards of 2 minutes. This depends on several factors such as cardiac output, muscle movement and ambient temperature.

 

So, what you are seeing has already happened, it is in the past.

 

Go on, you are in your kitchen; put your pulse-ox on.  Walk around and breathe, look at your reading, 98%. Now hold your breath. Time how long it takes to get to 90% (a moderate level of hypoxia approximating an oxygen pressure in the blood of 60 torr). I bet you can’t hold your breath that long. Why? Because as you are holding your breath the oxygen level in the blood drops fast. It is felt first in the brain. But because you are checking it at the periphery, deoxygenated blood will get to that location in the longest amount of time. Oh yes and you were walking around right.

 

Try it again after sitting for a while in one spot, sit on a couch for thirty minutes and repeat the test. Hold your breath until you reach a sat of 90%. It will take longer for the extremities to be perfused. Your brain will be hypoxic much sooner.

 

Now don’t try this again at the flight levels, where it might be a bit cooler, blood has pooled in the extremities.

 

Remember get your sat monitor up to 98% to start.

 

Remove your oxygen; your cerebral oxygenation will tend toward zero within one minute, one cardiac volume cycle. The only reason it doesn’t go there immediately is due to stagnant oxygenated blood being circulated, your oxygen to your brain is coming from your fingers, not from your lungs.

 

Now glance at you pulse-ox as you start to black out. What does it read? 98% give it a couple of minutes to adjust. Out of time.

 

Pressurized cabins have a cushion, even when they fail, they leak and the pressure does not go immediately to outside pressure, giving the crew (two pilots) time to put on their masks.

 

With unpressurized cabins you are already breathing outside the plane. And there is really nothing outside to breath.

 

25,000 feet  pB =282.4 mmHg

 

PAO2 = 21%(282.4-47 ) – (40)(1.25)

 

PAO@ = -0.566

 

Carl,

Thank you for posting on this topic. Since you are a respiratory therapist and teach this subject, we all respect your expertise and value your opinion.

It is certainly true that a pulse oximeter placed on an extremity does not measure instantaneous cerebral pO2. Nevertheless, as DXB has posted, peripheral arterial saturation measurements (SaO2) do reflect an overall SaO2 in the body. As you state in your post, they are of great value in the clinical setting. 

Similarly in the cockpit, those measurements present an overall measurement of SaO2. The limitation of any monitoring system is the frequency of measurements (and how often they are evaluated), and what is done with that information. The goal of the pulse oximeter is to warn of low SaO2. It is hoped that a pilot checks it frequently, and has the ability to respond to abnormal values. As such, it does provide useful information.

Many of our Mooneys are capable of flight over 12,500 ft. There is no question that at 25,000 ft the time to respond is brief, and the failure of the oxygen delivery system needs to be recognized immediately. And yes, the pilot must be able to still process the information and react appropriately.

While the time of useful consciousness at 25,000 ft may be 3-5 minutes, it is 20-30 minutes at 18,000 ft, and longer at lower altitudes. Thus, if a pilot does not feel "right", he can check his O2 saturation and hopefully respond appropriately. Even with a lag between cerebral perfusion and peripheral perfusion, there is ample time to repond at most of the altitudes we fly at. I recognize that the onset of hypoxia is insidious and that one of its effects is decreased cognition. Nevertheless on balance, having a pulse oximeter is more likely to warn of hypoxia than not.

When flying at these altitudes, it is important to be aware of the risks involved, the steps to mitigate them and all of the limitations therein. Although these pulse oximeters may not be ideal, at less than $100 they offer information that is not available otherwise and help mitigate the inherent risks.

[bradp]

I would like to clarify a couple of things about the post above questioning the utility of a pulse oximiter at altitude.

1.  There is no lag between central oxygenation and cerebral oxygenation except for the cardiac output that is diverted to the brain, heart and other high-oxygen consuming organs in states of cardiovascular stress.  In a person with a normal heart (i.e. you have a third class medical and were not a blue baby as an infant) there is perfect mixing of oxygenated blood as it leaves the heart.  The body doesn't get to decide that it is sending more oxygenated blood to the brain, but it does have a mechanism to preserve cardiac output to the brain (see #2, below).  

2.  If you are peripherally vasoconstricted for reason number (1), above, or another reason, like your cabin heat is off and you're going all Memphis Bell in the flight levels with Piloto's bomber jacket and no gloves, you will either get intermittent readings or will be unable to get a  reading on your pulse oximeter.  They may be unreliable, but they will mostly be unreliable by showing a low value or no value.   For this reason I recommend one with a pulse waveform (what we call a pleth waveform) - it will give you an idea of the quality of the measurement at any given time.  Carl is correct that muscle movement can affect a pulse ox reading negatively.  

3.  The time it takes for a red blood cell to get from the venous circulation to the arterial circulation is pretty low - and importantly less than the time of useful consciousness in the flight levels.   

4.  The brain cares about oxygen delivery to tissues.  For the math/medicine nerds in the group, Delivery of O2 to the tissues (DO2) is:

DO2 = cardiac output * oxygen content per mL of blood 

DO2 = cardiac ouput * [((SaO2%/100)*1.34*Hemoglobin concentration) + 0.003*PaO2)]

As you can see the real driver for oxygen content is how much hemoglobin is bound to oxygen.   The pressure of oxygen in the gas exchange parts of the lung drives how much oxygen is bound to hemoglobin.  Lance Armstrong might do 30 sec better in the flight levels because he drove up his hemoglobin levels (cheating bastard).  

5.  As alluded to previously, the reason you feel air hungry when you hold your breath is mostly due to the buildup of carbon dioxide in your blood.  People don't become nearly as air hungry with hypoxia - in fact with a normal carbon dioxide level (which will not be impaired in the flight levels) and a normal blood pH you can go on happy as a clam without feeling any need to breathe - ask the folks who have been to the altitude chamber.  

6.  The reason your oxygen saturations can last longer at seal level with holding your breath is as follows:

When I want to keep someone's oxygen saturations up for as long as I can when I am going to make them apneic on purpose is doing something called pre-oxygenation.  I do this when I place a breathing tube in someone.  Pretty much I try to let them breathe 100% oxygen at Sea Level for a period of time.  The purpose of this is to essentially wash out the 70 odd percent atmospheric nitrogen that out lungs are filled with with 100% oxygen.  An adult with normal lungs can last with a normal oxygen saturation for between 3 and 10 minutes completely apneic with this method.  That's a really long time in my book.  The reason is that you create a reserve by which oxygen delivery across the lung can occur.  You still build up CO2 over time, but this is a remarkably useful procedure.   I take care of infants and children, which have much less of a lung functional volume, a higher heart rate and higher tissue oxygen consumption, so instead of getting 3 minutes, I get 30 seconds-1 min of time to do what I need to do before they start dropping oxygen saturation levels.  

 

When you take a deep breath in and hold your breath, you are doing something similar but instead of filling the lungs with 100% oxygen you're starting out with 21%.  It's somewhat but not very useful to try to hyperventilate to wash out carbon dioxide from the lung prior to holding your breath - this is what those deep sea free divers do.   Your ability to hold your breath and maintain normal saturations will necessarily be less than if you pre-oxygenated with 100% oxygen. 

 

Now lets do the same thing in the flight levels.  You are entraining your lung with a lower total pressure of gas even if it's 100% (via a perfectly working non-rebreathing mask).  Cool.  Can you hold your breath for a time longer than at sea level with 21% oxygen?  Nope.  Why? Because the partial pressure of the 100% oxygen is still low because the atmospheric pressure is 400 mmHg instead of 760 mmHg.  You fill the alveoli with less pressure of oxygen (even though it's 100%) and you have fewer oxygen molecules per volume unit of alveoli.  Less driving pressure to get oxygen across the lung and bound to hemoglobin in the blood.  This also shows why it's really dangerous to use a nasal cannula in the flight levels - with that you are replacing 21% oxygen with 35% oxygen and a coordinate decrease in the percentage of nitrogen.  The atmospheric pressure is still what it is (Mt. Everest).  However, you just took what little ability to sustain a pre-oxygenation reserve and cut it significantly.  Having a small reserve may not mean much in terms of time (20-30 sec? Maybe...), but that 30 seconds of useful consciousness may be the difference between reaching for the backup oxygen bottle and not making it.  So please use a mask setup as per the regs if traveling in the FLs.

What does the body do when oxygen sats are lower?  What it can... namely your heart rate will increase to increase cardiac output and via that oxygen delivery equation get more ml/min of oxygenated blood to the brain and the heart.  You'll also breathe faster (you have both carbon dioxide measuring apparatus in your brain and you can sense hypoxia even though you don't feel as "air hungry" when hypoxic), and you'll divert blood from muscles and gut to brain and heart.  The brain is good at extracting every bit of oxygen it can your the saturation of blood that returns to your heart (the mixed venous oxygen saturation) will be lower.  I think Carl was describing this phenomenon of diverting useful cardiac output and increasing oxygen extraction in his post, above, but it should be recognized that a mechanism to achieve this is peripheral vasoconstriction and that should be reflected in the quality of the pulse-saturation waveform.

 

Long winded, but in summary a pulse-oximeter should be used on flights above (pick your altitude - depending on your lung health, age, personal reaction to altitude) 8,000 ft, 10,000 ft 12,500 ft.... I don't know the answer but that's for each of us to determine for ourselves.  Please use a pulse ox with the caveat that they are incredibly useful but not perfect almost real time measurements of what your oxygenation level is.  If you are feeling symptomatic and the pulse ox is saying 100% something may be wrong... use your backup oxygen and consider the possibility of carbon monoxide poisoning.  If you feel symptomatic and you're not sure if something is or what's wrong quickly get to a lower altitude now and then figure out your situation once your time of useful consciousness has been addressed. 

Stay safe up there...

- Brad

(my IRL credentials are Pediatric Critical Care Medicine Doc, Aeromedical Transport Doc, PhD in Molecular Physiology)

 

(@ Carl on the side - check your averaging for your pulse ox - in peds we keep the averaging super short, the delay you see may be a reflection of the averaging).  

 

 

 

[Danb]

while I'm no physician, thank god, I'm a lowly cpa but couldn't disagree any more with Carl's post regarding dangerous?  Are you implying to have no useful information albeit maybe not timely, do use xm weather well that must be dangerous..im not getting rid of my xm, adsb on the iPad or my two oximeters...my key is 

1. I do check the meter at least every 5 minutes just to be timely

2.Totally agree with TJ to include the airflow indicator as part of your scan, mine is over my yoke and almost continuously watched, but every 5 minutes when I put the oximeter on my finger I make sure to check the flow.

3. based on your comment's Carl provide a meaningful solution since this thread has turned into a remarkable learning tool

also as mentioned we are all different I need and use oxygen at 8000 ft. if I'm feeling good and lower if tired or don't feel sharp, the oxygen system in my plane is there for a purpose and therefore used often, I rarely fly above 13,000 ft. Learned to many lessons of what may occur there  i.e.. icing in July, hot cylinders ,chance of hypoxia, etc.

 

the great thing were doing is trying to learn and provide all of us with useful knowledge

Cnoe with respect your around good pilots, I kinda disagree I see to many pilots at my field who don't train, don't use checklists on and on..therefore I se many pilots unfortunately most are older who have that feeling of knowing it all and being invincible

All fly safe , have your own limits and be on this forum for yrs. to add to our knowledge

 

 

 

 

 

 

[mike_elliott]

 

Edit - according to CAMI's flyer these are the bases still providing chamber course. Contact CAMI for details :https://www.faasafety.gov/files/gslac/courses/content/36/467/PT_06272005_web.pdf

I have been working with the FAASteam Program manager Billy Hattaway who has contacts inside CAMI group to get this done for the Mooney Summit IV, TENTATIVELY scheduled for the first weekend in Oct, 2016. This is a rather dated FAA publication, and a few of the players have retired, budgets have been cut, etc. In otherwords, there is "red tape" not mentioned, but Billy is one of the best and we will get this done for next year. This year, the FAA "budget" stood in the way of the portable vomit comet and the oxygen deprivation chamber, and Tyndall was booked for our weekend (they had a couple spots for Oct 18th I believe). All said, let CAMI know your interested so they keep this alive! (and you keep alive)

[cnoe]

Thanks for your efforts to make this training/experience available to the community. With a service ceiling of 17,999' my J doesn't visit the flight levels but I found the course to be quite valuable nonetheless. I would encourage everybody/anybody to go through this training.

I'd like to add that as an avid snowboarder I seem to fare quite well with high altitudes but will still monitor my O2 sats when in the 10K+ range and will break out the nasal canula when needed. But what hasn't been said is that (my) O2 numbers will drop significantly when breathing is relaxed and shallow. Simply taking a couple of deep or deliberate breaths will raise my O2% by ~5 without any supplementary oxygen. If nothing else the pulse oximeter reminds me to take a deep breath once in a while. Similarly my wife reminds me regularly to do some calf pumps to prevent throwing a PE (also not a bad idea).

 

[Parker_Woodruff]

I'm with Ward's sentiments.  What you see on a web board is often a much nicer picture than the guys that don't participate in online safety discussion.

Edited September 18, 2015 by Parker_Woodruff

[mike_elliott]

The FAAsteam has some data on those that actively participate in wings seminars , activities and those that don't with respect to incidents and accidents and violations. The data heavily favors active participation in safety events

[peevee]

Thanks for your efforts to make this training/experience available to the community. With a service ceiling of 17,999' my J doesn't visit the flight levels but I found the course to be quite valuable nonetheless. I would encourage everybody/anybody to go through this training.

I'd like to add that as an avid snowboarder I seem to fare quite well with high altitudes but will still monitor my O2 sats when in the 10K+ range and will break out the nasal canula when needed. But what hasn't been said is that (my) O2 numbers will drop significantly when breathing is relaxed and shallow. Simply taking a couple of deep or deliberate breaths will raise my O2% by ~5 without any supplementary oxygen. If nothing else the pulse oximeter reminds me to take a deep breath once in a while. Similarly my wife reminds me regularly to do some calf pumps to prevent throwing a PE (also not a bad idea).

 

I find my altitude tolerance changes a lot with my cardio health. Last year I spent a lot of time hiking in and around the 12-14k range and I could monitor my o2 and be fine at 13,5 with little to no flow, this year I've been working too much and haven't been getting the exercise, and my o2 demands show it.

 

A lot of people quick to jump to hypoxia, is it not possible he had some other sort of health problem that incapacitated him? Heart attack, stroke, who knows.

Edited September 18, 2015 by peevee

[Andy95W]

I'm with Ward's sentiments.  What you see on a web board is often a much nicer picture than the guys that don't participate in online safety discussion.

So that means we really are just preachin' to the choir...

[Bennett]

We are really fortunate at San Carlos airport. The San Carlos Flight Center arranges Wings seminars every Wednesday night, and discussion meetings on most Saturday's. The subjects vary sufficiently to cover advanced topics for us crusty old timers, as well as new pilots. I am (pleasantly) surprised how well attended these seminars are. The meeting room is generally filled, with SCFC members able to monitor the seminars from home, via streaming video, and to send in questions for the presenters. The presenters are normally CFIIs, with others called in for their specialized knowledge and experience. We have had several sessions related to hypoxia and O2 gear. Sort of: "if they put on the seminars, they will come". It is great to have so many meaningful questions, and comments by the many truly experienced pilots who attend - quite a few retired military and airline pilots.

H

[ArtVandelay]

We are really fortunate at San Carlos airport.

Except you got some really long winded departure clearances...I had my Garmin think I had a stuck mike and it cut off my read back.

[carl]

Pulse oximeters are worn on the extremities; because of this location they present a lag between central oxygenation, cerebral oxygenation and peripheral oxygenation.

What I mean here, central and cerebral oxygenation are the same, the lag is in the peripheral oxygenation. There is a smaller lag with smaller patients simply do to size difference (and other difference).

The adult lag component can be seen on ICU patients with Licox placement, directly measuring cerebral PaO2

 

Pulse Oximetry gives a false sense of security that I believe develops by reading a saturation monitor and then believing you are ok, when you are hypoxic already. I have spoken to pilots who think a saturation of 90% equals a oxygenation of 90mmHg ( wrong is it is 60, Hypoxic ) 

 

 

 

The Alveolar gas equation absurdity does not exist. It is not an absurdity it is a reality. At these condition gas flow is negative and leaves the body. Yes this is incompatible with life, which is my point, when we are suddenly placed in that environment there is little time to recover.

How did Reinhold Messner climb Everest without oxygen?  He did it gradually allowing he body to adjust. He and the Tibetan Sherpa have 1) increased amount of hemoglobin so the oxygen carrying capacity is increased 2) Hyperventilation, he was able to lower his CO2 levels much lower than most, (the PACO2 was possibly  7–8 torr) 3) Amazing oxygen uptake through training and natural ability. Of course mountain breathing (pursed lip breathing) added a bit of positive end expiratory pressure. This shifts the alveolar equation into the positive.

  

 

Irish tiger

"I noticed one thing in the requirements - you HAVE to have a medical certificate to participate. My best friend (who is a physician by the way) is the only person that flies with me in the flight levels, and I want him to participate in an event like this sometime. He has no desire to learn how to fly, he could care less.

But - just because he's not an aviator and doesn't hold a medical certificate doesn't mean it won't be beneficial to him!!! I really want him to go"

He just needs a third class medical certificate, as you state, a student physical , he does not have to take any flight lessons at all. Just visit any AME.

 

 

 

 

What is your blood oxygenation when your saturation monitor reads 90%?

 

The solution? Never let hypoxia happen.

Nasal cannulas are workable to about 14,000 but above that I believe a personal improved standard should be used:

At least one pilot at the controls shall wear, secured and sealed, an oxygen mask that either supplies oxygen at all times or automatically supplies oxygen whenever the cabin pressure altitude exceeds 12,000 feet MSL;

 

Carl

 

[Bennett]

Reading through all this commentary (which I find truly informative) I now realize the sort of Russian Roulette I was inadvertently playing in my many FL 250 to F 270 flights across the country. Sure I always kept a back up (to the built in bottle), portable O2 bottle hooked up with its own regulator and masks, and a pulse oximeter that I looked at occasionally, but I see that I was truly lucky. As I mentioned earlier in this thread I now fly a J, and I won't be up to those flight levels in my current airplane.

As to the long winded IFR clearances, we have been trying for years to just say: Clearance Alfa for 30 and Clearance Bravo for 12. The wording never seems to change: For runway 30 departures: "After take off, maintain runway heading, climb to 2000', within 2 miles of the airport turn right to a heading of 120, maintain 2000" until crossing the Oakland 165 radial (see, we still have use for the VORs), climb to 4000', expect 9000' five minutes after departure, squawk xxxx, contact Nor Cal at 135.65"

[carusoam]

Carl,

thank you for the detailed follow-up. The technical level of the details is greatly appreciated.

 

PV,

Keep following along.  We won't know the cause of Dr. Moir's accident for some time, if at all...

The top of this thread covers the logic of why the conversation has started and continues.

It may have helped to start a separate thread to cover the speculation aspect.  In this case, lacking facts, we are speculating.  But, we are having a real time discussion of a safety topic with high level technical people.  The level of respect for the lost Mooney brother is unequalled.  The timeliness is beneficial.

If and when Dr. Moir's family reads this thread, I'm sure they would approve.

As for heart attacks and strokes, those are a little more complex to fend off while flying solo.  But I am interested in the topic.  A while ago, I had a health issue. I had enough knowledge from these types of discussions to prioritize a course of action. I Put the odds in my favor, rolled the dice and it worked...now I have the good fortune to work with people recovering from heart attacks, strokes and other head injuries.

Best regards,

-a-

Edited September 18, 2015 by carusoam

[aviatoreb]

Do any of the medical people I know I bet -

I would guess that if a person is in a state of health close to having a stroke or heart attack, that the stress of high altitude flying, even on proper legal O2 devices, might be more inclined to bring it on at the most inconvenient time while at FL25 as solo PIC.  So perhaps while not a hypoxia event, a heart attach or stroke might be a altitude event precipitated by the condiitions and stress of the physical environment.  Perhaps that same heart attack or stroke might have indeed occurred at some other time in the near furture, but not while in such an irrecoverable scenario?

Related - does anyone know how often people die each year due to health events while behind the wheel of a car?

[DXB]

Pulse Oximetry gives a false sense of security that I believe develops by reading a saturation monitor and then believing you are ok, when you are hypoxic already. I have spoken to pilots who think a saturation of 90% equals a oxygenation of 90mmHg ( wrong is it is 60, Hypoxic ) 

The Alveolar gas equation absurdity does not exist. It is not an absurdity it is a reality. At these condition gas flow is negative and leaves the body. Yes this is incompatible with life, which is my point, when we are suddenly placed in that environment there is little time to recover.

 

I think there is a misunderstanding here of the alveolar gas equation (AGE) that is clouding the discussion.  A negative result for pAO2 by the AGE is not an indicator of O2 leaving the body at low inspired pO2.  The equation reads out absolute alveolar pressure (PAO2), not a pressure differential or direction of flow. There is no such thing as an absolute pressure below zero- it's an irrational concept.  Further, the steady state assumptions that are the basis for this equation break down at low atmospheric pO2 - thus it simply should not be applied at high altitude.  Here is a second review on the equation- this one goes through its mathematical derivation and details how its founding assumptions no longer apply as inspired PO2 drops:  http://ceaccp.oxfordjournals.org/content/4/1/24.full.pdf    Although there may be extreme altitudes where a sudden drop in PO2 reverses the A-a gradient, I am not at all convinced this is the key factor at FL250.  Given the complexity of the system, I don't know an easy way to predict the A-a gradient at such marginally survivable elevations.  There is acute compensatory hyperventilation to sustain PAO2 going on simultaneously with a precipitous drop in central venous pO2 which is essentially what enters the pulmonary capillary bed. I'm sure a real physiology expert could say more than me. However the AGE is inadequate to address this question.  

Regardless, these details seem of limited practical value to the average pilot. Awareness of expected lengths of useful consciousness by altitude is useful however. Based on this info, I think that SaO2 monitoring is of great practical value at the non-FL altitudes and but agree with you that it might give pretty short warning at FL250 with a sudden and complete O2 flow loss.  I also think it is of practical value to realize that the range of 88-92 or so on the monitor (or a PaO2 of 60mmHg) is very imprecisely correlated with the degree of hypoxia defned at the tissue level, since many other variables are at play to determine the latter.  I'm sure you've noticed that 90 creates noticeable impairment for some folks and none for others.  I think striving to keep >95 provides a reasonable cushion for most folks.  

Lastly I agree that there is likely a short lag between onset of  serious hypoxia at the tissue level in the brain and a getting very low reading on the monitor at the finger. It would be fun to discuss why over a beer, perhaps also with bradp above, but may get a little cumbersome here and not add much light.

 

[carusoam]

Any insight towards long term effects to a pilot's brain regarding the altitudes we fly and the lower O2 levels we are measuring?

Is there an SPO2 level we should be avoiding?  Or, that occurs at lower numbers than we are awake for?

thank you for sharing your insight,

-a-