LT42 (More Detail) - de-icing systems are normally used by the crew if the OAT or Outside Air Temp is 10c or below and there is moisture in the air. De-icing spray is used when ice is forming on the leading edges or engine cowls. A piece of ice breaking off and entering the engine shaft could cause a burnout or damage to the engine. Cancellations normally occur when there is ice around runways, taxiways, aprons and or visibility is down to 100ft with crosswinds.
