VISIBILITY
In
meteorology, visibility is the
distance at which an object or light can be clearly seen. It is important for all forms of traffic, especially for aviation. Visibility is often reduced by air pollution and high humidity. Various weather stations report these phenomena as haze or mist. Fog and smoke can reduce visibility to near zero, making flights extremely dangerous. Heavy rain causes not only low visibility, but the inability to brake quickly. The international definition of fog is visibility of less than 1 km; mist is visibility of between 1 and 2 km and haze from 2 to 5 km. Visibility of less than 100 meters or 1/16th of a mile is usually reported as zero. Under these conditions, airports might be closed. If visibility or ceiling is below minima a controller doesn’t clear a pilot to descend from transition level and gives instructions to go around. A captain sometimes decides to divert to the alternate. #visibiity
