Anyway, you might want to open your copy of the FAR AIM and on page 821 in Chapter 7 “Safety of Flight”, Section 1 “Weather”, page 821 you’ll find the ASOS/AWSS (Metar) says wind direction in ten of degrees from TRUE north. The ASOS is Metar information which is written. This is just one example.

Additionally the Weather Services book AC 00-45F (Oct. 2007) Section 3:Observed Text Products Page 3-6 “It is coded in tens of degrees relative to true north using three figures.” Also on pages 5-21, 5-47, 5-57 etc. are good pages for you to look at. This is an Advisory Circular and while ACs are not necessarily regulatory in nature like the FAR, you’d have to agree that neither is the AIM. Yet you use that.

What I’m saying is that you can’t simply demand someone to “prove it” against only the FAR / AIM. Especially when Steve’s question was not even about regulations, but rather about information.

My understanding is this: Heading is the direction of the longitudinal axis of the aircraft. In navigation, the reference direction is mag norht and the heading is known as mag heading (MH). Wind can change the aircraft’s path over the ground to differ from its heading, the result being the ground track. MC is based on mag north. (Some countries refer to it as desired track.) VOR and ILS CDI’s show the aircraft’s actual ground track is deviating from the MC.