For those interested please check the link below. I have posted a scan of the relevant page from the A.I.P. Canada. Remember when calculating the correction required it is the "height above the altimeter source" that is important. Another thing to bear in mind is that the 100NM safe and Minimum Sector altitudes only give you 1000' clearance from the highest obstacle within 5 miles (at least here in Canada). When flying VFR it is even worse the Minimum quadrangle altitudes depicted on the 1:500,000 scale VFR charts only provides 100 m (328') clearance above obstacles in that grid square. In the USA it is only 200'.
After spending every winter for the last 10 years making these corrections all I can say is "Hi to Low, Lookout Below", as far as I am concerned there is not an altimeter in existance that can automatically make the required corrections. If this were the case then all "modern" aircraft flying the high flight levels in winter where it is usually below ISA would all be flying at non assigned ATC altitudes. What if Honeywell uses a different correction logarithim to Sperry, there are just too many variables. This is the reason we use a standard altimeter setting in the flight levels, so that all aircraft in a particular geographic/meteorological area are using the same setting and therefore are prone to the same error.
http://www.geocities.com/canuck_av8r/
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Keep the shiny side up and the dirty side down.
Canuck Av8r
ICQ 26305263