Engine anti-ice
Hey guys
I'm a bit confused on the utilisation of the anti-ice as it's written on the FCOM:
Engine anti-ice must be ON during all flight operations when icing conditions exist or are anticipated,ExCEPT during climb and cruise when the temperature is below -40 SAT.Engine anti-ice must be ON before and during descent in all icing conditions,including temperatures below -40 SAT.
What's get me confused are the EXCEPT part of it and the below -40 SAT.the below -40 means (-39,-36 etc...) or (-41,-45 etc...)?