Mountain High Cannula/Mask?

Does everyone stick to the 18k limit for the cannula and 25k for the mask,

or are these limits considered advisory only?

I use the blue mask if I'm planning to go above 18k and have been above 27k with no issues. (It is an unhelpful fire drill at 17k changing systems in a cockpit, so if you plan to go high, just start with the mask. You can fit it on the ground and hang it from the neck strap. Then pull the top strap back over the head when you get above 10k if you wish.)

It's not clear to me the regs or the physiology eliminate the cannula above 18k if you can remember to use your nose, but the mask covers the bases and looks cool in those wave picts.

What works can vary widely depending on the person, so pulse oximeter is useful to verify things are working. (A brain in la-la land is not dependable to do this on it's own. Especially in and above the 20's.)

Dress warm now...

On Tuesday, October 1, 2019 at 6:45:06 AM UTC-4, John McLaughlin wrote:
Does everyone stick to the 18k limit for the cannula and 25k for the mask,

or are these limits considered advisory only?

The legalitys are not so clear, but practically it is about remembering to breathe only with your nose with the cannula. Something I felt i could do, and so far have remembered. It is much easier to hydrate and communicate with the cannula. Just don't forget...

RR

On Tuesday, October 1, 2019 at 3:44:11 PM UTC-4, RR wrote:
On Tuesday, October 1, 2019 at 6:45:06 AM UTC-4, John McLaughlin wrote:
Does everyone stick to the 18k limit for the cannula and 25k for the mask,

or are these limits considered advisory only?

The legalitys are not so clear, but practically it is about remembering to breathe only with your nose with the cannula. Something I felt i could do, and so far have remembered. It is much easier to hydrate and communicate with the cannula. Just don't forget...

RR

There are several reasons any given person might not breathe well on a cannula at high altitude, mouth breathing is only one. Here's another: It is really easy to hyperventilate on a cannula at 20+K. Trivially easy in fact.. If you must use a cannula above 18K (which I recommend against), do not skimp on the O2, don't use a dumb ass "oxy-miser" anything above 18K. Turn up the flow. If in doubt, turn it up some more. Not a bad idea to monitor heart rate as well as O2 saturation. Tachycardia is reliable indicator of breathing problems, and it will catch hyperventilation (O2 saturation will not, key word alkalosis).

It's much easier to breathe well (and reliably) on a mask, provided the mask fits and seals acceptably well. If you aren't breathing well, hydration and communication are going to cease to matter.

T8

Tango Eight wrote on 10/1/2019 3:47 PM:
On Tuesday, October 1, 2019 at 3:44:11 PM UTC-4, RR wrote:
On Tuesday, October 1, 2019 at 6:45:06 AM UTC-4, John McLaughlin wrote:
Does everyone stick to the 18k limit for the cannula and 25k for the mask,

or are these limits considered advisory only?

The legalitys are not so clear, but practically it is about remembering to
breathe only with your nose with the cannula. Something I felt i could do,
and so far have remembered. It is much easier to hydrate and communicate
with the cannula. Just don't forget...

RR

There are several reasons any given person might not breathe well on a cannula
at high altitude, mouth breathing is only one. Here's another: It is really
easy to hyperventilate on a cannula at 20+K. Trivially easy in fact.. If you
must use a cannula above 18K (which I recommend against), do not skimp on the
O2, don't use a dumb ass "oxy-miser" anything above 18K. Turn up the flow. If
in doubt, turn it up some more. Not a bad idea to monitor heart rate as well
as O2 saturation. Tachycardia is reliable indicator of breathing problems, and
it will catch hyperventilation (O2 saturation will not, key word alkalosis).

It's much easier to breathe well (and reliably) on a mask, provided the mask
fits and seals acceptably well. If you aren't breathing well, hydration and
communication are going to cease to matter.

Does it matter which face mask is used? The one that came with the Mountain High
EDS units I have is very basic, with a very small cavity, so I think it would not
increase the amount of CO2 you breathe. I'm assuming it's the CO2 content that's
the important factor - is that true?

They do have a mask with a rebreather bag, so perhaps that's the one you should use?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

On Wednesday, October 2, 2019 at 8:52:12 AM UTC-4, Eric Greenwell wrote:
Tango Eight wrote on 10/1/2019 3:47 PM:
On Tuesday, October 1, 2019 at 3:44:11 PM UTC-4, RR wrote:
On Tuesday, October 1, 2019 at 6:45:06 AM UTC-4, John McLaughlin wrote:
Does everyone stick to the 18k limit for the cannula and 25k for the mask,

or are these limits considered advisory only?

The legalitys are not so clear, but practically it is about remembering to
breathe only with your nose with the cannula. Something I felt i could do,
and so far have remembered. It is much easier to hydrate and communicate
with the cannula. Just don't forget...

RR

There are several reasons any given person might not breathe well on a cannula
at high altitude, mouth breathing is only one. Here's another: It is really
easy to hyperventilate on a cannula at 20+K. Trivially easy in fact.. If you
must use a cannula above 18K (which I recommend against), do not skimp on the
O2, don't use a dumb ass "oxy-miser" anything above 18K. Turn up the flow. If
in doubt, turn it up some more. Not a bad idea to monitor heart rate as well
as O2 saturation. Tachycardia is reliable indicator of breathing problems, and
it will catch hyperventilation (O2 saturation will not, key word alkalosis).

It's much easier to breathe well (and reliably) on a mask, provided the mask
fits and seals acceptably well. If you aren't breathing well, hydration and
communication are going to cease to matter.

Does it matter which face mask is used? The one that came with the Mountain High
EDS units I have is very basic, with a very small cavity, so I think it would not
increase the amount of CO2 you breathe. I'm assuming it's the CO2 content that's
the important factor - is that true?

They do have a mask with a rebreather bag, so perhaps that's the one you should use?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

I've had good luck with (decent quality, form fitting) re-breather mask systems on constant flow. I don't breathe well on the EDS / cannula system at high altitude. My breathing tends to get sort of "lazy" by 16 - 18K and I find I have to use one of the higher delivery modes to maintain high saturation. Re-breather mask fixes that and CO2 seems the most likely reason.

I have not tried the MH masks. I've seen one (blue rubber, apparently decent quality) that looked like it might be worth a try.

Minor rant: *Any* hard plastic mask (Aerox & Mountain High are both guilty of selling such) that looks like an emergency medical single use mask has no place in the cockpit... you would honestly just be better off sucking on the end of the hose. I've seen these things literally fall apart before first use as someone unwrapped the sealed plastic bag it was shipped in. It's completely unconscionable that anyone would sell you something this crummy as part of a life support system.

While I'm at it, I'd encourage folks to take a skeptical look at their oxygen delivery gear. The old style Aerox needle valve/rotameter is notorious for breaking under normal handling, as are the old green plastic barbed fittings. Expect anything plastic or rubber to become more fragile when cold soaked, don't expect that these O2 system manufacturers have done any durability or cold soak testing of their products: they obviously haven't. Again... I find it completely unconscionable that anyone sells such rubbish for life support purposes, but it's out there, beware.


T8

On Tuesday, October 1, 2019 at 3:44:11 PM UTC-4, RR wrote:

The legalitys are not so clear [...]

FAR 23.1447 spells it out (for certificated aircraft). Above 18K the requirement is for a mask that covers nose and mouth.

The fact that some people can get away with a cannula at 26K (once) does not mean that this is a sound practice. We've had two hypoxia incidents (that I know of) at Mt Washington due to pilots emulating certain old timers. Physiology varies. Physical fitness doesn't seem to be a factor (in fact casual observation suggests the reverse :-)).

T8

On Wednesday, October 2, 2019 at 7:17:16 AM UTC-4, Tango Eight wrote:
On Tuesday, October 1, 2019 at 3:44:11 PM UTC-4, RR wrote:

The legalitys are not so clear [...]

I should have been more specific, the legalities in experimental aircraft (many if not most of our gliders) are not so clear.

And I am sorry if I implied a recommendation. I am just speaking of my own experience (18 years of diamond and Lenny climes) accompanied with, pulse oximeters (from back when they were expensive) and backup systems at hand.

I totally agree with T8 about not scrimping on the Ox. No using the oxisaver flow levels. But for me, with full beard and mustache, I know what is being delivered to my nose, where I would be concerned about leakage from a mask.

Ox at altitude is not something to take lightly. And single place aircraft require real diligence in acquiring the knowledge about your personal reaction to hypoxia. Know your symptoms, and learn to react quickly.

One thing that is very important to know is the Ox saturation curve has a "kink" in it at 25k. Flights to 24k are like scuba diving, flights above are like cave diving. You need to have redundant systems. Everyone knows climbers have ascended Everest without Ox and think they can descend if something goes wrong, but the amount of "useful conciseness" you have above 27k is measured in seconds not minutes.

RR



FAR 23.1447 spells it out (for certificated aircraft). Above 18K the requirement is for a mask that covers nose and mouth.

The fact that some people can get away with a cannula at 26K (once) does not mean that this is a sound practice. We've had two hypoxia incidents (that I know of) at Mt Washington due to pilots emulating certain old timers. Physiology varies. Physical fitness doesn't seem to be a factor (in fact casual observation suggests the reverse :-)).

T8

https://www.faa.gov/pilots/training/...%2061-107A.pdf

Page 13 is the table of useful consciousness versus altitude, and is surrounded by a pretty good discussion.

Above 22k, note that the time to descend can be longer than the time to think. So a backup system and being willing and able to come down really fast need to be thought through beforehand.

RR is right, something happens in the 20's. Perhaps the partial pressure of O2 in the blood and air get close?

On Wednesday, October 2, 2019 at 2:02:08 PM UTC-6, wrote:
https://www.faa.gov/pilots/training/...%2061-107A.pdf

Page 13 is the table of useful consciousness versus altitude, and is surrounded by a pretty good discussion.

Above 22k, note that the time to descend can be longer than the time to think. So a backup system and being willing and able to come down really fast need to be thought through beforehand.

RR is right, something happens in the 20's. Perhaps the partial pressure of O2 in the blood and air get close?

This article is quite interesting.
https://www.airspacemag.com/military...eet-117615369/