I don't quite agree - it applies to "installed" oxygen systems where you are legally bound by the oxygen system AFMS.
Too bad my POH only mentions that there is an oxygen system but not what I am allowed to do with and what not 
Back to the original discussion (flying through frontal weather): with the detailed weather data available today (like sat24, ogimet, etc), would it work to file a deviating route to circumvent a front?
Do ATC have radar weather service available? Are they able to vector you around nasty weather?
The trips I did so far where all in VMC on top, like this:
I guess I was just lucky with the weather so far :-) However, the IR rating is paying off, as the trip on the photo above (to Isle of Man) could not have been done VFR, as the clouds that day had a base of around 600ft...
This is how it looked below the clouds:
with the detailed weather data available today (like sat24, ogimet, etc), would it work to file a deviating route to circumvent a front?
Sure, you can file whatever CFMU validates. However, deviating because of weather is something one does in the air so I wouldn't file a different route unless it was absolutely clear the more direct route wouldn't work.
Do ATC have radar weather service available? Are they able to vector you around nasty weather?
Typically not. What they do know is where airplanes ask for deviations so they often tell you about it and suggest you execute similar manoeuver but they normally don't have weather information on their screens and don't have time or the qualification to give you weather briefings.
FIS are usually better informed. In Germany they have all kinds of weather information available, such as precipitation radar, METARs, strikes etc. They are also used by airlines to get weather information (the infamous Ryanair "read all METARs of Europe to me" requests).
I can't tell what date that IFR Mag article is but it refers to some stuff from 2005 ... and I think that is out of date.
Indeed it is.
The FAA will initiate action to revise the definition to reflect the interpretation articulated in this letter ...
I wonder if they ever got around to doing that?
I fly through frontal weather and don't see the problem. I try to see if it is a weak front or not. In most cases, you can fly through them no problem. Buy this video at Sportys on Frontal weather:
Then, the IR cloud tops temperature charts I combine with my Skew-T diagram showing ambient versus dewpoint temps all the way up to FL200+ for any place on earth. See:
The combined IR cloudtop chart with the Skew-T diagram gives me good information. When the dew and ambient temp lines are close together, I might doubt the outcome and will ask ATC to confirm the top-of-clouds with a commercial airline pilot departing.
The data comes from the GFS model. I find it to be reliable when looked at within 1 day before flight. OK.
In below zero clouds, most of the time you don't get any ice. If you have an escape, e.g. decending to below freezing level and still being save above the ground and obstacles, I would not have a problem climbing through or flying in below zero clouds if the total picture or what weather to expect is ok and with an escape at hand.
I try to see if it is a weak front or not
That's important, yes.
I tend to look at the pressure gradient at the front and if it is slow then the front probably won't be very aggressive. For example the front here to the west of Ireland is like that.
Whether this is valid I don't know. Certainly tightly curving fronts are bad news, like the one wrapped around the Low further west of Ireland.
The IR images are very good. If a front tops out at FL300 and it looks solid... ?
In below zero clouds, most of the time you don't get any ice
Not a statement I would like to make
I get ice most of the time, in IMC between 0C and about -10C. It's only a question of how long it takes to appear and how much there will be.
Presumably this is aircraft type dependent to some degree. And there is a significant difference between a TAS of say 140kt and a TAS of say 200kt, at which the aerodynamic heating on leading edges is several degrees C.
I have read statements from pilots who said they almost never get ice, and then I read (or hear) of a near death encounter by that pilot in which he nearly killed himself.
One always needs a viable exit strategy when in freezing IMC, unless de-iced and then it depends on the conditions...
Slight thread drift:
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.
Actually you do, but not necessarily about the wx. You get Pireps, TFRs (nasty stuff, can pop up at very short notice), status of MOAs, NOTAMS, forest fires (smoke) etc, etc. The actual wx forecast is IMHO the least important bit here, as you do get that from a variety of online sources. That said, you can easily land somewhere remote to refuel and find an automated pump but no internet connection. 1-800-WX-BRIEF is your friend!
Well, I surely want to get back home safe when flying and I don't underestimate the risk of ice. In frontal weather you will experience icing more rapidly than in non-frontal weather. Clouds at below zero temp do not - per definition - give icing problems. Flying through frontal weather is something you can study about. In many cases it is not a big deal, but learn to distinguish the difference.
In frontal weather you will experience icing more rapidly than in non-frontal weather.
I agree based on traditional teaching but my by far the worst icing incident (details written up here previously) was in stratus cloud, nimbostratus no doubt, nowhere near any fronts, and it would have been fatal to any low power non deiced aircraft (say a PA28) within 10 mins. TB20, maybe 15-20mins.
