# Airplane in Wind: Wind Velocity Calculation

Velocity unit
If your airspeed indicator and compass indicate a velocity of the airplane
with respect to air of: = at °
But your GPS receiver indicates a ground speed and bearing of = at °
Then the wind velocity in which you are flying is = at °

Note: The wind direction in this calculation is the direction of air motion, not the direction from which the wind is coming. So if you call a wind from the north a "north wind", then the air motion direction is south and you would enter 180° for the wind angle.

 Alternate calculations: Ground Velocity Desired heading and resultant
Index

Relative velocity

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# Discussion of Airplane in Wind

 Navigation directions are usually expressed in terms of compass angles as illustrated. The vector addition necessary to calculate resultant velocity is carried out by calculating the components of each vector.
There are some practical problems associated with this calculation: you can either convert compass angles to standard angles, or do the calculation in compass angles with the relationships shown. If you calculate the standard angle for the final bearing, it can then be converted to compass angle. A final problem is the arctan problem with calculators and computer languages: you have to check the quadrant to be sure you get the correct angle.

### Calculation

Index

Relative velocity

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