magnetic heading of winds?

Kirbhund

Kirbhund

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Kirbhund
Here is an e6-b wind correction angle question: When I go to a site like aviationweather.gov and they give a wind direction at 3k feet such as 0220...do I need to correct for mag variation of the winds or is this already calculated?
 
Winds aloft are TRUE, surface winds are magnetic. So you have to apply the correction for variation (and your WCA and your compass deviation) before you come up with your compass heading.
 
I go by:
"If it's written, it's true!":wink2:
 
In general (and as is printed on most E-6B's and flight log computation forms), you take true course off the chart, apply the true wind from the Winds Aloft Forecast to get true heading, then apply variation from the chart to get mag heading, and finally apply deviation from the compass correction card to get compass heading.

The reason surface winds are reported as magnetic (rather than true as for winds aloft) is that the primary purpose for surface wind data is to select a runway for use, and runways are numbered with reference to magnetic north.
 
Ron Levy said:
The reason surface winds are reported as magnetic (rather than true as for winds aloft) is that the primary purpose for surface wind data is to select a runway for use, and runways are numbered with reference to magnetic north.
Click to expand...

Aren't surface winds in METARs and TAFs given in True, and on ASOS/AWOS/ATIS over the radio in Magnetic?
 
Thanks for the information. So if I am understanding this correctly I can apply mag variation after I do a wind correction angle using true wind direction and true course?
 
Start with True Course (TC) and your True Airspeed (TAS) and your Wind information.

Use your E6B or other computer to find your Wind Correction Angle (WCA).
Take your True Course and your Wind Correction Angle to find your True Heading (TH).

Then take your True Heading and your Mag Variation (MV) to find your Magnetic Heading (MH).

Then take your mag heading and your compass deviation to find your compass heading (CH). So

CH=TC +/- WCA +/- MV +/- deviation.

The order matters since your forecast winds are in TRUE. Lots of times people will take the true course, convert it to a mag course, and then apply the winds, which doesn't work out because the winds aren't in magnetic.

Hope this helps.
 
TMetzinger said:
CH=TC +/- WCA +/- MV +/- deviation.

The order matters since your forecast winds are in TRUE. Lots of times people will take the true course, convert it to a mag course, and then apply the winds, which doesn't work out because the winds aren't in magnetic.

Hope this helps.
Click to expand...

Don't forget to factor in the compass error! :stirpot:
 
BillTIZ said:
He did, that was the "deviation" , the last item in the formula. :popcorn:
Click to expand...

I always remember that the deviants are in the cabin!

Of course, since where we live the magnetic variation is only 1 or 2 degrees, I don't typically include it. Need to work on that!
 
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