Looking for A-14 (or similar) pressure breathing diluter demand regulator

The A-14 system, so I thought, is not a true pressure-demand type required at greater altitudes, but is a diluter-demand pressure regulated system with manual pressure valving available(?) Not to be confused with "pulse-demand" EDS. If needed I have a diluter-demand mask with microphone that can be loaned to Keith for his adventure.

While a cup of blood (or water for that matter) will boil at that altitude, circulating blood in a semi-sealed body will likely not (look up "Myth, boiling blood"). Mouth saliva would freeze first. Amazingly, experts say the astronaut in "2001 a Space Odyssey" caught in open space could theoretically have survived his short exposure.

If there's one locally, take a "flight" in an altitude chamber to discover how you function under hypoxic conditions (or you can try breathing a mixture of N2 with air/O2 to get your blood sat to 90% and less).

The A-14 system, so I thought, is not a true pressure-demand type required at greater altitudes, but is a diluter-demand pressure regulated system with manual pressure valving available(?) Not to be confused with "pulse-demand" EDS. If needed I have a diluter-demand mask with microphone that can be loaned to Keith for his adventure.

While a cup of blood (or water for that matter) will boil at that altitude, circulating blood in a semi-sealed body will likely not (look up "Myth, boiling blood"). Mouth saliva would freeze first. Amazingly, experts say the astronaut in "2001 a Space Odyssey" caught in open space could theoretically have survived his short exposure.

If there's one locally, take a "flight" in an altitude chamber to discover how you function under hypoxic conditions (or you can try breathing a mixture of N2 with air/O2 to get your blood sat to 90% and less). "drunk" pilot: https://www.reddit.com/r/videos/comm...are_emergency/

The diluter-demand function of the A14, from what I have read, occurs below a certain altitude, 30,000' if I recall correctly. In this mode the mixing chamber mixes cabin air with O2 and the amount of O2 increases with altitude. Above this altitude it supplies 100% O2. The pressure breathing function is a separate function that has different dial settings for increasing altitudes. Here the pressure of the O2 supplied not the mixture to the mask increases. The markings on the A14 dial suggest 5 different pressures for settings of Safety, 41,000', 43,000', 45,000', & above 45,000'. Not sure why the 1st dial setting is marked Safety but it is the 1st position when the dial is turned off normal.

I've read the same about blood boiling. I think, as you have pointed out, they are referring to an uncontained and uncirculating liquid and meant to make a point about how low the pressure is. Articles I've read also use statements like "seems to boil" instead of boils. I guess the body can contain the vapor pressure sufficiently so it doesn't reach atmospheric pressure and really boil. Apparently the skin will expand and early experiments with dogs in space or a vacuum chamber discovered this. Saliva boiling on the tongue makes sense.

I do plan to get experience in a hypobaric chamber and am hoping they will let me use my own mask, regulator, and bottle however, I suspect this might be considered a liability for then to allow. I still plan to ask. What better way to test the performance of the system I intend to use at FL350-400!

Just updating my initial post with availability and cost of New Surplus (NS) A14 regulators manufactured by FPI in 1990 with part #1550. These are new in the original OEM packaging. Stock is currently 10 units and the cost is $600 per unit. Let me know if anyone needs a unit and I will put you in touch with the shop in CA that is stocking these. Also, if anyone knows of a shop that can overhaul these units besides FPI, and especially someone out west, please advise.

Jim
VVII

Fuzzy memory says the pickup was in BC (Hope?), ultimately destined for
Oklahoma...

Bob W.

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Your fuzzy memory is correct about Hope. You picked up the Vancouver Soaring Associations L-13 C-GZEU. Dearly loved and much missed by me - and many others in the club. It was the first glider I ever flew in, I did my first solo and also made my first flight as a licensed pilot in that ship too. She was essentially timed out though as Transport Canada enforced the factory life limits and getting an extension of 250 hours would have been financially prohibitive. I remember coming out to the airport so you could pick her up. Sorry to hear about the re-entry difficulty and I certainly wish the wing AD hadn't grounded the L-13 a few years later.

On Tuesday, October 30, 2018 at 3:32:17 PM UTC-6, Keith Schwab wrote:
Hi Everyone!
I'm looking for an A-14 regulator, or something similar, to prepare for higher altitude wave flights in the Sierra. Curious if anyone has an one laying around they might be willing to part with or lend for a season.
Thanks!
Keith



My club's (Soaring Society of Boulder) 1-34 got totaled last summer, and it has an old and lately unused A14 regulator in it. Contact the ship's manager, Phil, at .

I would like to correct a couple of statements made here with respect Bob Harris’s altitude record flight. My apologies for being slow to respond.
1) Bob Harris did not limit his climb “because he couldn't keep his mask on�. He terminated the climb because he believed one of his two oxygen systems had malfunctioned.
2) However, the statement that he was “forced down when his oxygen system started to fail� is also incorrect. His subsequent investigation showed that both oxygen systems were operating within specification. The problem was they were not operating identically. As Bob pointed out in his presentation to the World Gliding Championship at Benalla, Australia the following year, differences in the regulators’ pressure settings, stiction between the components, the lack of vibration in the sailplane to address that stiction and the fact that the regulators were at or near their operating limit, resulted in a substantial difference in the pressure he felt in his mask when he switched between the two systems. He interpreted this difference as an indication that one of the two had failed, but later determined it had not.
3) He did not suffer from any medical condition as a result of his record flight.
Mike Koerner

Thx for the clarification. Proof that second hand information often gets corrupted in the re-telling! Guilty of passing on the "mask coming off scenario" that was not verified. Is there a written account somewhere of this flight? Also curious with how he dealt with his exhalation moisture. Heard he vented his mask to the outside of the AC. Maintaining visibility can be a lot of work at these fridgid temperatures.

Jim
VVII

On Sunday, December 23, 2018 at 9:59:15 PM UTC-8, wrote:
I would like to correct a couple of statements made here with respect Bob Harris’s altitude record flight. My apologies for being slow to respond.
1) Bob Harris did not limit his climb “because he couldn't keep his mask on�. He terminated the climb because he believed one of his two oxygen systems had malfunctioned.
2) However, the statement that he was “forced down when his oxygen system started to fail� is also incorrect. His subsequent investigation showed that both oxygen systems were operating within specification. The problem was they were not operating identically. As Bob pointed out in his presentation to the World Gliding Championship at Benalla, Australia the following year, differences in the regulators’ pressure settings, stiction between the components, the lack of vibration in the sailplane to address that stiction and the fact that the regulators were at or near their operating limit, resulted in a substantial difference in the pressure he felt in his mask when he switched between the two systems. He interpreted this difference as an indication that one of the two had failed, but later determined it had not.
3) He did not suffer from any medical condition as a result of his record flight.
Mike Koerner

Thanks Mike. After reviewing Bob Harris's article I have a few observations:
1) the regulators he used we MD-2s not A-14s. These were manufactured by Cobham Life Support.
MD-2 regulators are obsolete; they were the 2894 series and they got replaced by 29255 series regulators. Very similar units. No idea how these compare to A-14s except they were both rated to ~50k'.

2) the account I heard, but did not verify, was that Bob terminated his flight because he couldn't keep his mask on (due to high pressure on the mask).. You note, and the article confirms, that he reported what he thought was a failed regulator (delivering higher pressure than expected). Is it possible that these reports are related i.e. the regulator he thought had failed was delivering higher pressure than the other one - and so it as forcing his mask off? Maybe a minor point but maybe not. At some point, if the mask is not tight enough it may be forced off and this is something to be prepared for. I added an extra strap on my mask as a backup to the 8 snap connections on my A-11 helmet for this reason.

3) I had heard, but did not confirm, that he vented his mask to the outside but in his article he clearly states he frosted up above 32,000' and was flying on instruments by 39,000' has he had zero visibility! I also experienced significant canopy icing on both my flights to 25k' and 28k'. I was able to "scrape and wipe" to maintain visibility but I expect this could be an overwhelming task at 30k' and above. I am looking at ways to apply film "windows" on both sides of my canopy and also vent my exhaled air to the outside. This is another significant issue to address.

Appreciate your feedback. It's obvious that lot's can go wrong attempting these high flights and the more accurate info we can learn from the better prepared we can be.

I also fly with an oximeter and have found the readings to be very informative for evaluating cannula versus mask performance. However, it would appear that even these can be misleading, if I recall the recent SSA article correctly, so again, good to know and more work to be done.

Jim
VVII

On Wednesday, December 26, 2018 at 5:47:38 PM UTC-7, wrote:
On Sunday, December 23, 2018 at 9:59:15 PM UTC-8, wrote:
I would like to correct a couple of statements made here with respect Bob Harris’s altitude record flight. My apologies for being slow to respond.
1) Bob Harris did not limit his climb “because he couldn't keep his mask on�. He terminated the climb because he believed one of his two oxygen systems had malfunctioned.
2) However, the statement that he was “forced down when his oxygen system started to fail� is also incorrect. His subsequent investigation showed that both oxygen systems were operating within specification. The problem was they were not operating identically. As Bob pointed out in his presentation to the World Gliding Championship at Benalla, Australia the following year, differences in the regulators’ pressure settings, stiction between the components, the lack of vibration in the sailplane to address that stiction and the fact that the regulators were at or near their operating limit, resulted in a substantial difference in the pressure he felt in his mask when he switched between the two systems. He interpreted this difference as an indication that one of the two had failed, but later determined it had not.
3) He did not suffer from any medical condition as a result of his record flight.
Mike Koerner

Thanks Mike. After reviewing Bob Harris's article I have a few observations:
1) the regulators he used we MD-2s not A-14s. These were manufactured by Cobham Life Support.
MD-2 regulators are obsolete; they were the 2894 series and they got replaced by 29255 series regulators. Very similar units. No idea how these compare to A-14s except they were both rated to ~50k'.

2) the account I heard, but did not verify, was that Bob terminated his flight because he couldn't keep his mask on (due to high pressure on the mask). You note, and the article confirms, that he reported what he thought was a failed regulator (delivering higher pressure than expected). Is it possible that these reports are related i.e. the regulator he thought had failed was delivering higher pressure than the other one - and so it as forcing his mask off? Maybe a minor point but maybe not. At some point, if the mask is not tight enough it may be forced off and this is something to be prepared for. I added an extra strap on my mask as a backup to the 8 snap connections on my A-11 helmet for this reason.

3) I had heard, but did not confirm, that he vented his mask to the outside but in his article he clearly states he frosted up above 32,000' and was flying on instruments by 39,000' has he had zero visibility! I also experienced significant canopy icing on both my flights to 25k' and 28k'. I was able to "scrape and wipe" to maintain visibility but I expect this could be an overwhelming task at 30k' and above. I am looking at ways to apply film "windows" on both sides of my canopy and also vent my exhaled air to the outside. This is another significant issue to address.

Appreciate your feedback. It's obvious that lot's can go wrong attempting these high flights and the more accurate info we can learn from the better prepared we can be.

I also fly with an oximeter and have found the readings to be very informative for evaluating cannula versus mask performance. However, it would appear that even these can be misleading, if I recall the recent SSA article correctly, so again, good to know and more work to be done.

Jim
VVII

I've used clear acetate (sorry can't recall the thickness, but thick enough to hold shape without wrinkling). I've used both sheets and pieces cut from rolls. I tape them to the interior of the canopy using Scotch Magic Tape (easier to remove or re-position though not clear). The slight air gap seems to be enough to keep frost from forming.

Frank Whiteley