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damien created the topic: Volmet, true or magnetic
I've jumped straight to CPL and I'm having trouble knowing what's weather forecast is true and whats in magnetic.
I can't see anything in the Bob Tait Met book that specifically states what Volmet, Metar etc are in.
Can anyone help please?
John.Heddles replied the topic: Volmet, true or magnetic
Presumably you are concerned only with wind direction.
The best place to sort out the story is via the AIP, which can be downloaded from the Airservices Australia website if you don't already hold a copy.
Run a search on "wind direction" and you will determine that the magnetic/true differentiation is tied up with "runway operations": wind direction for runway operations is in magnetic, otherwise it will be true. (reference Gen 184.108.40.206 at page Gen 2.1-1).
Similarly, run a search on "runway operations" and, while the expression is not defined explicitly, it clearly relates to matters associated with the aeroplane's specific runway-related activities.
So, in summary, if you are getting information relating to your specific takeoff and landing or related activities in real time, ATC will call wind direction in magnetic. All other occasions will be called as true. Information such as ATIS/AWIS will be magnetic, aerodrome forecasts will be true and so on.
Engineering specialist in aircraft performance and weight control.