Wake Turbulence

The disturbance to air that is caused by the passage of an aircraft through it. It is caused by airflow around wingtips, not the expulsion of air behind jet engines or propellers, and presents a serious hazard to any aircraft following closely behind, and on the same flight path as another.

Wake Turbulence Separation

The requirement that a controller provide specified spacing between an aircraft following another, or crossing its flight path.


A geographical location that describes an aircraft’s flight path across the ground. In Terminal Areas, usually defines a turning point.

Weight Category

A system of classifying aircraft in terms of the likely wake turbulence hazard they could create for aircraft using the airspace through which they have passed. There are four classifications – Super, Heavy, Medium and Light – and each is defined by aircraft weight. Weight category is a factor in determining Wake Turbulence Separation Standards.