Plain English Meaning

Ice that builds up on the outside of the airplane while flying through cold, wet air. It makes the aircraft heavier, less aerodynamic, and harder to control.

Full Definition

Ice that forms on the external structure of an aircraft — wings, tail, fuselage, propeller, antennas, windscreen, and other exposed surfaces — when the aircraft flies through visible moisture (clouds, rain, drizzle) at temperatures at or below freezing. Airframe ice adds weight, disrupts the airflow , increases , reduces , and can block or .