# HD and TL Winds

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Is there some formula for calculating the head or tailwind component of wind if it's direction and velocity are know? On the TOPCAT Take-off page there is an indication of what the HD wind would be on a runway. Say 230 at 10 would be a 8 HD wind on Runway 25. I am primarily interested in winds aloft such as 268 at 45 along a 285 track. What would the HD wind be in that case and how would it be determined. Also this sentence appears in the MD-11 Manual FMS 10.18 Item 5 TEMP/WIND " Wind bearing is always along the aircraft track". I guess this means track not heading of the aircraft?Thank youMichael Cubine

Michael Cubine

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From wikipedia:

Assume: A=Angle of the wind from the direction of travel WS=The measured total wind speed CW=Crosswind HW=HeadwindThen CW=Sin(A)*WS HW=Cos(A)*WS[/Quote]so given 268 at 45 along a 285 track.285 - 268 = 27degreesCW = Sin(27) * 45 = 20HW = Cos(27) * 45 = 40

Paul Smith.

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