GM1 Article 2(141) Visibility

CAA ORS9 Decision No. 1

(a) The two distances which may be defined by a given visibility have different values in the air of a given extinction coefficient. Visibility based on seeing and recognising an object is represented by the meteorological optical range (MOR) (Article 2(141)(a)). Visibility based on seeing and identifying lights varies with the background illumination (Article 2(141)(b)).

(b) The definition of visibility applies to the observations of visibility in local routine and special reports, to the observations of prevailing and minimum visibility reported in METAR and SPECI, and to the observations of ground visibility.