What is the most prevalent condition for engine icing to occur?

The most prevalent condition for engine icing to occur is cold ambient temperatures. Engine icing typically forms in conditions where the air temperature is low enough to allow moisture in the air to freeze upon contact with engine surfaces. This can happen during takeoff, landing, or other phases of flight when the engine may be exposed to cold ambient air.

While high humidity at altitude can contribute to icing in some specific situations, it is less of a direct condition compared to cold temperatures. High engine speed during flight and low engine speed during ground operations do not necessarily create the kind of conditions conducive to icing, as the critical factors are primarily temperature and moisture in the environment. Hence, cold ambient temperatures remain the predominant factor leading to icing in engine components.