Bizzy Old Chap/Girl,
The point is that because it is stated in UK/US docs that ATIS winds are to be in magnetic, this is what pilots expect to receive. In fact I've yet to come across an overseas airfield that broadcasts in true!
The whole reason for having an ATIS is to stop pilots having to call the Twr, if I called you from 100 miles out I wouldn't expect you to pass the wind in true!
ATC are responsible for what goes out on the ATIS so I don't think it's unreasonable to expect them to add or subtract the variation to the true wind before making the tape!
I'm afraid the old 'we just pass what the met man gives us' argument doesn't hold much water for military ATC as it clearly states in JSP 318A that ATCOs must remember to convert the wind supplied by the Met office to magnetic (surely this was taught during basic training?)
The real question being asked here is; if pilots and ATC in the rest of the world know that the ATIS wind is supposed to be magnetic why is it that some UK ATCOs don't?
The obvious answer being that 4 degrees variation makes bugger all difference, so the theory has got lost in the sands of time and we're into the 'but we've always done it this way' mentality. A shame really because one begins to wonder what else wasn't taught at ATC school :-)
[This message has been edited by Specaircrew (edited 06 March 2001).]
[This message has been edited by Specaircrew (edited 06 March 2001).]