Originally Posted by M Invernoz
So the critical point of the OAT is below 10°C and/or with a narrow temp/dew pt spread?? No matter if the aircraft has FADEC or not, or autostart or not??
It seems that You are after the definition of icing conditions here - those are relevant for takeoff, but only rarely for engine startup. The exact definition varies a bit by aircraft type: on the Fokker 70/100, it is "OAT below +5°C AND spread below 3°C", on the DH8 on the ground, it is OAT at or below 10°C AND visible moisture (i. e. precipitation of any kind, drifting or blowing snow or the like, or mist with visibility below 1600m). So it is not really possible to give You an answer suiting all types, engines and also operators.