Real great stuff here. Thanks guys.
Wait a minute, I hijacked this topic from Mach and I'm not going to give it up without a fight!
I do fly into cold conditions, in Alaska, Canada, Europe and the USA and I have paid particular attention to the altimeter displays. The reason I am proposing that the manufacturers of the airplane, (B744 in my case) and the Air Data Computer, put it in their manuals that temperature is automatically compensated, is because that is the only way the performance of the altimeters I use can be explained. If they were not compensated then I would see all the things you say I would.
If the airport is cold, that does not necessarily mean the air above it is also. The cold air holds less water vapour, the tropopause may be lower (in the Frozen North), and the lapse rate could be wild. It is not uncommon for a marked inversion to form just above the ground, especially in Canada,such that for approach and departure you could be actually above ISA. Using the airport temperature to compensate the altimeter manually does not make any sense if you have a better way...and modern airplanes have, through the CADC, accurate temperature, (TAT and OAT) at all times. Far better to use that, would you not agree? Or is it a principle to you that the CAA is always right?
Read on if you acknowledge that there are better ways to apply the correction than using the airfield temp.
So is it too hard a leap of faith that the Boffins have anticipated the need to have a more accurate way of presenting altitude and have incorporated automatic compensation? And if they have, that they put that information in their manuals?
Feel free to knock off now and check for yourself. See the references above.
And is it hard to believe that the CAA (etc) and those guys in your company who write the Ops Manuals are not aware or do not care about this change? They have to write their regulations for all airplanes after all and if you want to apply the correction when it may not be necessary, it will not hurt you, so go ahead.
At altitude, the airplane with the new computer equipment will have much more accurate altitude and speed displays, and it is not unreasonable for any temperature error to be smaller than the altimeter error of the older airplane. I hope I don't come close enough to a 707 to find out for sure. The deviations from ISA are small at altitude anyway, and so are the differences due to temperature.
As well as being accused of being at odds with "all the Canadians", trying to kill my passengers in Zurich (I have been there many times in the winter and not killed anyone yet), now I am being told how to write up defects on my airplane.
Still you (but not me, apparently) are entitled to your opinion.
By the way, do you know the altimeter tolerance for the B744?
I am not trying to change anyone's procedures, it would be far better for you to research it yourself if you have an interest. I am not disagreeing with anything written here, as it applies to a Pressure Altimeter.
I just read that the Universe is flat. Are we going to crap on the guy who suggested that too?