I have read somewhere that using O2 meters are not covering the full risks involved with flying relatively high in unpressurized cabins, but can’t remember the issues involved.
Mountain High is approved to 20,000’. Above that, you will need a different system anyway.
What seems to missing
Most likely there are very few pilots who fly with a wide variety of passengers and do it at high altitudes and unpressurised. So those using this kit just buy the cannulas from MH. I have gone for years since I last bought some, and I fly with a fair number of people.
Mountain High is approved to 20,000’.
Is that the O2D2 spec?
I’ve been to FL210, which in the summer is more than likely 22000ft or so, without any difficulty, but it requires very deliberate breathing. Not recommended for “novice” passengers or children.
I have been up to 240 with one passenger, and 210 with my co-owner, and on both occasions I was fine, as witnessed by my oximeter readings, but the other guy was quite seriously incapacitated.
If I would have to buy today, I would probably try a bunch of these: https://webshop.vivisol.nl/salter-zuurstof-neusbril-1600-soft-kort.html
I would have to cut off the connector but they most likely will just work and fit well in the O2D2 and are dirt cheap. There are a lot of other providers of cannulas. I would try some out and once you are happy, buy a batch.
As for altitude, I have taken the cannulas up to FL250 in the Cirrus, but that is far from ideal and probably not legal. I just don’t want to deal with a face-mask and my wife and I won’t be able to do a normal conversation at that altitude at all. You have to focus on breathing and not on talking. My wife is a lot more sensitive to flying at such altitudes so we tend to stay lower at FL180 most of the time. Sometimes, it helps to climb to FL250 but even then we sometimes cannot outclimb the weather.
The Cirrus Perspective has this Auto Descend Mode – an alert system where if you e.g. fly at FL250 and do not touch any buttons (other than the radio button), the system will try to alert you as the pilot and ask you to respond. If you do not respond by pushing some buttons, the aircraft will initiate an auto descend into FL180 first (if I remember it correctly) and level off, then descend even further. I have tested it once in collaboration with London Control inbound the UK over the North Sea in 2013 to see how it worked. I took a picture at the time. A long time ago.
Peter_G wrote:
Mountain High is approved to 20,000’.
The O2Dx-2G have in their manual that facemasks must be used above 18000ft. But that only reflect the FAA regulation (FAR 23.1447). Not sure there is an equivalent requirement in CS23 or part-NCO.
Most likely that FAA requirement is based on some NASA or military experiment based on constant flow.
And as already noted, different individuals have very different tolerance.
The EASA NCO rules place responsibility firmly with the pilot, which is great.
Interesting. Did not know that the face mask is not explicitly required under EASA rules above 18000 ft.
a) The pilot-in-command shall ensure that all flight crew members engaged in performing duties essential to the safe operation of an aircraft in flight use supplemental oxygen continuously whenever he/she determines that at the altitude of the intended flight the lack of oxygen might result in impairment of the faculties of crew members, and shall ensure that supplemental oxygen is available to passengers when lack of oxygen might harmfully affect passengers.
b) In any other case when the pilot-in-command cannot determine how the lack of oxygen might affect all occupants on board, he/she shall ensure that:
(1) all crew members engaged in performing duties essential to the safe operation of an aircraft in flight use supplemental oxygen for any period in excess of 30 minutes when the pressure altitude in the passenger compartment will be between 10 000 ft and 13 000ft; and
(2) all occupants use supplemental oxygen for any period that the pressure altitude in the passenger compartment will be above 13 000 ft
So, provided that you take responsibility for checking your own and your pax’ welfare (using, presumably, pulse oximetry) you are on your own.
About the EDM – Emergency Descent (not Descend, sorry) Mode: Automatic descent begins after one minute of no response initially to 14,000 feet for 4 minutes, then to 12,500 feet thereafter.
