MET.OR.255 AIRMET

A meteorological watch office shall:

(a)issue AIRMET when the competent authority has determined that the density of traffic operating below flight level 100, or up to flight level 150 in mountainous areas, or higher, where necessary, warrants the issue of AIRMET in combination with area forecasts for low-level flights;

(b)cancel the AIRMET when the phenomena are no longer occurring or are no longer expected to occur in the area;

(c)ensure that the period of validity of an AIRMET is not more than 4 hours.