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**Bertie the Bunyip[_25_]** · April 18th 08, 06:42 PM posted to rec.aviation.piloting,rec.aviation.student

terry wrote in news:ea7c4c43-ffdf-4802-825b-
:

On Apr 18, 9:05Â*am, Bertie the Bunyip wrote:
terry wrote in news:375462b0-66e7-4ed0-b45d-
:

On Apr 18, 7:10ï¿½am, Stefan wrote:
WingFlaps schrieb:

Perhap we are at crossed purposes but an ARFOR does not refer to
an
airfield -that's a METAR and not all fields issue them. So in
this
case how can QNH give field elevation unless it's an ISA day?

Again: QNH gives *by definition* the field elevation. If an ARFOR
gives
you a QNH, then it is related to one well defined spot on the
surface.

As I understand it ( In Australia) the QNH in an ARFOR must be
within
5 mbar of the "real QNH" Â*- ie what gives you field elevation for
a
ny
place within that area. otherwise the area will be broken up into
sub
areas and no 2 adjacant sub areas must differ by more than 5 mbar.
That way the errors which Wing flap alludes to, and must certainly
exist in non ISA atmosphere, would result in errors of no more than
150 feet between aircraft using either the correct AFROR QNH or the
airfield set QNH

Yipes! Are you studying to be an astronaut?

Are there any openings?

Sure! Lots of applicants though.

Bertie