Inkognito wrote:
NCO.OP.190 – half an hour maximum between FL100 and FL130 without oxygen
But if the reg number of your plane starts with N and FAA 91.211 applies, then you get an automatic O2 boost and you will be fine until 12000 for much longer :)
In all seriousness, beside legality which varies, I wonder the actual physiological impact and limit, but they probably vary from individual to individual
12500 even.
A lot of people get a headache at 12k. One FI I flew with to Prague could not read instruments at 12.5k.
I used to fly at 13500 over the Sierra Nevada quite often for 30 mins or so. Never had a problem and never had a passenger report a problem either.
Years ago we flew to Yellowstone, at 16000 or so to try and avoid the hot-weather turbulence (unsuccessfully). It was in my 182 which had functioning O2 at the time. My kids couldn’t be bothered with it and just went to sleep. My daughter said later “I knew I should just go to sleep when I read the same page 3 times and didn’t remember anything about it”.
I wonder what the legality is of flying at 12000 N-reg in Europe with FAA and EASA licenses without O2? Outside EASA-land it’s clearly legal.
roznet wrote:
In all seriousness, beside legality which varies, I wonder the actual physiological impact and limit, but they probably vary from individual to individualThe border between full and limited compensation is between FL100 and FL120, always depending on the individual of course – smoking is an extremly bad habit in this regard. I guess Europe assumes there are more smokers around and thus gold plated the FAA rules.
Inkognito wrote:
not doing CVFR
Schhhh! 
We had the oxygen debate already many times here. In short: In my opinion it is readily possible without oxygen, my instructor flew many times around half of the world without oxygen. He saw my oxygen installation and asked me something like what I was doing with that, just for a few knots more? I’m also typically below oxygen levels because of the kids. There is even a route over the alps where you only need to hop for less than half an hour to FL140 to cross the alps IFR. But if weather permits I even stay at about FL100 and cross them VFR. Other than that FL100 is perfectly fine.
Just on the topic of Oxygen, for anyone who does use it a bit, I was recommended the Precise Flight demand conserver. Rather than allowing the o2 to just be continuously running, it senses the drop in pressure as you breathe in. It really works incredibly well and for some long flights at 170 two of us hardly made a dent in the main tank – i think we lost about 80bar in five hours. Only allowable up to 180 and then above you need constant flow, but doubt that’ll be the case very much except Alpine IFR.
Check the oxygen thread. Search for O2D2.
Inkognito wrote:
NCO.OP.190 – half an hour maximum between FL100 and FL130 without oxygen
Actually this does not apply if the PIC is able to determine if oxygen is needed or not. This can e.g. by done using a pulse oximeter. NCO.OP.190 (a) + AMC/GM.
Airborne_Again wrote:
Actually this does not apply if the PIC is able to determine if oxygen is needed or not. This can e.g. by done using a pulse oximeter. NCO.OP.190 (a) + AMC/GM.Very helpful, thanks!
AMC1 NCO.OP.190(a) Use of supplemental oxygen
DETERMINATION OF SUPPLEMENTAL OXYGEN NEED
When determining the need for supplemental oxygen carriage and use, the pilot-in-command should:
(a) in the preflight phase:
(1) be aware of hypoxia conditions and associated risks;
(2) consider the following objective conditions for the intended flight:
(i) altitude;
(ii) duration of the flight; and
(iii) any other relevant operational conditions.
(3) consider individual conditions of flight crew members and passengers in relation to:
(i) altitude of the place of residence;
(ii) smoking;
(iii) experience in flights at high altitudes;
(iv) actual medical conditions and medications;
(v) age
(vi) disabilities; and
(vii) any other relevant factor that may be detected, or reported by the person; and
(4) when relevant, ensure that all flight crew members and passengers are briefed on hypoxia
conditions and symptoms, as well as on the usage of supplemental oxygen equipment.
(b) during flight:
(1) monitor for early symptoms of hypoxia conditions; and
(2) if detecting early symptoms of hypoxia conditions:
(i) consider to return to a safe altitude, and
(ii) ensure that supplemental oxygen is used, if available.
GM1 NCO.OP.190 Use of supplemental oxygen
GENERAL
(a) The responsibility of the pilot-in-command for safety of all persons on board, as required by
NCO.GEN.105(a)(1), includes the determination of need for supplemental oxygen use.
(b) The altitudes above which NCO.OP.190(b) requires oxygen to be available and used are
applicable to those cases when the pilot-in-command cannot determine the need for
supplemental oxygen. However, if the pilot-in-command is able to make this determination,
he/she may elect in the interest of safety to require oxygen also for operations at or below such
altitudes.
(c) The pilot-in-command should be aware that flying below altitudes mentioned in NCO.OP.190(b)
does not provide absolute protection against hypoxia symptoms, should individual conditions
and aptitudes be prevalent.
GM2 NCO.OP.190 Use of supplemental oxygen
DETERMINATION OF OXYGEN NEED — BEFORE FLIGHT
Detailed information and guidance on hypoxia conditions and symptoms, content of the briefing on
hypoxia and assessment of individual conditions may be found in the EASA leaflet ‘Hypoxia’.
DETERMINATION OF OXYGEN NEED — IN FLIGHT
Several methods for monitoring hypoxia early symptoms may be used and some methods may be
aided by personal equipment, such as finger-mounted pulse oximeter. Detailed information and
guidance on entering hypoxia conditions, on hypoxia symptoms early detection, and on use of personal
equipment such as finger-mounted pulse oximeters or equivalent may be found in the EASA leaflet
‘Hypoxia’.
