terry <tfmann@iprimus.com.au> wrote in news:375462b0-66e7-4ed0-b45d-
e6e089f79270@s50g2000hsb..com:
> On Apr 18, 7:10 am, Stefan <stefan@mus._INVALID_.ch> 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" - ie what gives you field elevation for any
> 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?
Bertie