Is there clear air/VMC at filed cruise level? If NO, is filed cruise level above or below 0°? Obviously if the answer to both is no, the flight is a NOGO.
Not necessarily if the temp at cruise is say -20...
Peter - it's performance, not O2 really. FL120 is as high as I can sensibly get with an normally aspirated 180.
Jason - I can't get up high enough to be outside the freezing range ;)
Jason - I can't get up high enough to be outside the freezing range ;)
Got it, sorry!
The IFR Magazine's take on what constitutes FIKI in FAA's terms:
"Reduced to basic terms, known icing conditions exist when visible moisture or high relative humidity combines with temperatures near or below freezing. Since clouds are a form of visible moisture, flying through clouds at an altitude that is near or below freezing would constitute flight into known icing conditions."
"Flight into known icing conditions when the airplane flight manual or pilot operating handbook prohibits such flight would constitute a violation whether the aircraft accretes ice or not."
I can't tell what date that IFR Mag article is but it refers to some stuff from 2005 e.g.
In explaining their definition of known ice, Loretta E. Alkalay, FAA Regional Counsel, referenced Administrator v. Curtis, NTSB Order No. EA-5154 (April 29, 2005). Here, the court ruled that conditions conducive to icing exists whenever near- or below-freezing temperatures and moisture exist together in a given area. It didn't matter that there were no reports or forecasts of icing conditions at any altitude anywhere near the route of flight.
and I think that is out of date.
That notorious "Known Ice is all flight in IMC below 0C" position existed for a period of time, and made most IFR flying in the winter, and almost all high altitude IFR flying in the summer, illegal.
It's a good magazine though. I tried to get a subscription to it after a friend gave me a pile of copies, but was totally unsuccessful in contacting the publishers by post, email or fax. Maybe they don't want foreign customers.
This US AOPA article suggests that US pilots struggle with cloud top estimates just as much as European ones.
I find this suprising, because US weather data is so much richer.
It's hard to know what to make of this, because e.g. my understanding is that very few US pilots phone up 1-800-WX-BRIEF like those of us who trained in the USA were told to do. Most reportedly get the data from the internet. I could never understand how one can get a useful briefing in a phone conversation - other than very basic stuff like the tafs or metars.
Peter/achmha,
At FL 200+ using the O2D2 with cannulas do you change the setting to mask.( I'm I right in thinking the mask setting is continues flow of oxygen) Also how practical is it if you had to change from cannulas to mask at that altitude.
Rob,
I never use a mask but keep it available just in case (not the O2D2 mask, the one that attaches directly in case the O2D2 fails). I do not adjust the O2D2 because it automatically senses the altitude. However, I constantly monitor my oxygen saturation. Constant flow dries out the nose and wastes oxygen.
This "18 000ft requires mask" is an FAA thing, not relevant in Europe and even under FAA jurisdiction, it is unlikely that an F-16 will fly by and take a picture of you not wearing a mask!
I don't change to a mask at any level up to my FL200 ceiling, but as you suggest I have used the Mask setting on the O2D2, to increase the blood o2 to ~95%, at FL190-200.
The flow is not continuous in the Mask setting. It is still pulsed.
Continuous flow just empties your cylinder even faster than the engine empties the wings 
You need to carry a mask and have it handy in case you or somebody gets their nose blocked up - or wants to sleep, and kids especially sleep with their mouth open so they would get hypoxic.
This "18 000ft requires mask" is an FAA thing, not relevant in Europe
I don't quite agree - it applies to "installed" oxygen systems where you are legally bound by the oxygen system AFMS. See the reference here. You are bound by whatever AFMS you have in all airspace. The AFMS is approved by the State of Registry and you are bound by that in all flight, everywhere, unless local airspace regs are stricter still (which the EASA ones are, above 10k ft...).
It seems that the FAA has not approved any installed oxygen AFMS unless it had that 18k rule in there, but then we are talking about really ancient planes here. Almost no new turbocharged plane has come out in the last 30 years - apart from the SR22. And there were no demand regs back then. Even the (barely usable) Nelson / Precise Flow demand regs were near-useless with a cannula at 18k (I know; I had them; one had to open them up to the "therapeutic" position i.e. constant flow) and they came out only c. 10 years ago. So basically all installed systems were intended for continuous flow and this is IMHO what led to the 18k=mask rule.
What IMHO the 18k=mask rule doesn't apply to is portable o2 kits. But I think Rob has a Seneca with an installed system, so he can use an O2D2 if he checks that the 1st stage regulator output pressure matches the O2D2 input pressure spec (somewhere around 20psi). It may or may not, and if it is too high then there are pressure reducers one can buy. If it is too low then he's stuffed...
and even under FAA jurisdiction, it is unlikely that an F-16 will fly by and take a picture of you not wearing a mask!
That's always true
Rob, have a look at the O2D2 manual.
If your blood oxygen level falls below a critical value (i.e. below 90%) you can increase the oxygen flow to a higher level.
From the manual:
Then there is the R/M mode, which will provide the maximum oxygen flow regardless of altitude. This should be used only in an emergency.
