"Newps" wrote in message =
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Roy Smith wrote:
In article ,
Newps wrote:
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John R. Copeland wrote:


Chip, you didn't mention enroute altimeter settings being different =
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surface ones.
I've seen that condition in the Rocky Mountains, but I can't =
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recall
if I've ever seen it in the central and eastern U.S.

Controllers issue altimeter settings from ground stations. Where =
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would they come from?
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You get them off DUATS like the rest of us?
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Yes, and they come from ground stations. There are no special enroute =

airborne stations in the mountains.

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.