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Aviation Oxygen (merged)

" unless of course the cockpit windows get blown out! "

all that has already happened - e.g. BEA BAC 1-11 l/h cockpit window was blown out as result of a maintenance error (using the wrong screw size). The pilot (Capt) sitting next to that window could be rescued. The circumstances were grateful because it occured at medium altitude and not at FL390 ...

EDxx, Germany

If you are in a pressurised aircraft, you wouldn't need oxygen. Isn't that the point of pressurisation?

You have gaseous oxygen for the emergency masks. In light jets this is rarely (never?) done by the chemical generators which you get on airliners.

I'd put fairly sizeable money on this +23 to -60°C change NOT happening in seconds, unless of course the cockpit windows get blown out!

I think that is what those masks are for.

There was that famous Lear accident where the windows were frosted over following an apparent loss of cabin pressure. I don't know how to work out the temperature drop from 15psi to say 3psi but surely the absolute temperature would drop in proportion to the pressure loss, or something like that? It would get very cold going suddenly from 15psi to 3psi - regardless of the outside being -57C or whatever.

All that stuff about water in oxygen is bollox. The industrial oxygen extraction process doesn't leave any significant water in there. Maybe something like 0.1%. Oxygen goes liquid at -183C and you would be hard pushed to have any liquid water still around by then.

Administrator
Shoreham EGKA, United Kingdom

Lenthamen, Jet-Techs in Lelystad will be able to fill your bottle with aviation approved oxygen. Give them a call.

Jørgen

EHLE, Netherlands

Lenthamen, Jet-Techs in Lelystad will be able to fill your bottle with aviation approved oxygen.

Thanks for the info, JayBee. Going to give them a call...

BTW: I ended up ordering the O2D2 pulse regulator for the front seats, and constant flow for the rear seats... I don't fly with passengers on the back seat that often, so its a good compromise.

I was at a local scuba store in Amsterdam this afternoon and they refused to fill my cylinder because it did not contain a CE marking. My cylinder has a US DOT marking, but that did not count... :-)

Next to the connection (DIN or CGA 540), also the conformity marking is something to consider before buying a cylinder...

I was at a local scuba store in Amsterdam this afternoon and they refused to fill my cylinder because it did not contain a CE marking. My cylinder has a US DOT marking, but that did not count...

Welcome to the "variable world" of scuba shops and the variable IQ of their workers

I used to get this kind of stuff, even variably from time to time in the same shop. One of them asked me for an oxygen certificate which I didn't have, obviously, and he gave me a Sherlock Holmes look and said "you are not a real diver are you????".

So I now rent the big cylinder from British Oxygen and have no more hassle.

Another thing they started doing here: I have 2 air cylinders, both marked for GROUND USE ONLY (paint spraying mostly). The rules require a 5 year test for those, against a 2 year test for ones used in scuba. But the shops are now saying that I could cover up the marking with a sticker and then go scuba diving with them, so they won't refill them unless within the 2 year test date. I can buy new ones online for the cost of a test (which is 2 tests; one for the cylinder and one for the valve, apparently)...

Administrator
Shoreham EGKA, United Kingdom

On the what is O2 and corrosion/freezing risks.

There IS a material difference in O2 SPECIFICATIONS (that is the minimum percentage O2' allowable water vapour, other gases, delivery process, inspection process, certification, blah blah).

O2 for use in welding actually has a higher spec than medical or ABO (which both allow for significantly lower levels of O2 and material water vapour content). However, ABO and medical generally have a specific testing process to confirm the cylinder really is full and has not been screwed up at the fill plant (I.e. accidentally filled with nitrogen). This is a largely hypothetical risk in the developed Western World, but can happen in LDCs.

The Oxygen that is actually bottled will always be created through cryogenic distillation, so will have no water and no material other gases (Argon impurities are likely if the plant doesn't separate out Argon due to the similar boiling points)

So welding oxygen will be fine (unless there has been a filling error and it is not actually oxygen). The most likely error would be Nitrogen (as other gases like Hydrogen, CO, syngas, etc are generally filled in a different plant or at least on different lines)

EGTF

Do you still use cannulas when above 18000' and get sufficient oxygen levels, or do you use the recommended masks

Do you still use cannulas when above 18000' and get sufficient oxygen levels, or do you use the recommended masks

I think it is a law requirement to use oxygen masks above 18000ft. I did some flights at FL200 and we achieved around 95% oxygen saturation using the normal EDS setting. "AeroPlus" from this forum is flies up to FL250 using the regular EDS cannulas.

I think the masks is just too much of a hassle. Just carefully watch your O2 level, and increase the oxygen level on the demand regulator if more is needed...

I think it is a law requirement to use oxygen masks above 18000ft

If you have a fitted oxygen system then you are supposed to do what the AFMS for it says. Ref FAR 23.1447 - note the word "installed".

If you have a portable system then you can do what you like, IMHO.

The regulations on the use of oxygen above a certain altitude applies to all systems, however - FAA above 12500ft over 30 mins (etc) and EASA above 10000ft (etc).

I have found masks to be essential anywhere near FL180, until I got the Mountain High O2D2 demand regulator which dispenses the gas so effectively, with a pulse right at the start of each inhalation cycle, that it delivers (for me) 95% blood O2 at FL200 using a cannula.

Administrator
Shoreham EGKA, United Kingdom
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