"John R. Copeland" wrote in message
...

In the Rockies, there are ground stations at widely varying elevations.
I've guessed that ATC might not use settings from airports in deep valleys
for enroute settings, wherever more representative values are available.
The terminology I've heard used at specific locations is something like:
"XXX altimeter nn.nn, Area altimeter nn.mm."
I don't really know how the "Area" numbers are established,
but I'd certainly want to use the local airport setting for landings.


Where did you hear "area altimeter nn.nn"?