Description

This article summarises the origin of wind velocity measurements made at airports and communicated to aircraft to assist their safe take off and landing. It also provides some guidance on how this information should be applied by flight crew, which concerns aircraft performance calculations, operating within prescribed AFM limits and the tactical handling of the aircraft during take off and landing.

What is wind velocity?

Velocity is a vector, which simply means that it is defined by two parameters, speed and direction. A specification of wind velocity therefore requires that both wind direction and wind speed are given. Wind direction is always given as a radial measure in degrees stating the direction from which the wind is blowing. Wind speed may be given in either knots (nautical miles per hour) or metres per second depending upon the procedures of the State concerned.