When do you need to use Engine Anti-Ice?
Icing conditions exist when the OAT is 10C (50F) or below during ground operations, take off, initial climb or go-around or:TAT is 10C or below inflight and visible moisture (clouds, fog with vis less than 1 mile, rain, snow, sleet, ice crystals, and so on) is present, or standing water, ice or snow is present on the ramps, taxiway or runways.