Plain English Meaning

Build-ups. In icing, it means the ice that gathers on the aircraft as it flies through freezing moisture.

Full Definition

Accretions are layers or deposits of material that build up gradually on a surface over time. In aviation icing contexts, the term refers to ice that accumulates progressively on aircraft surfaces — wings, propellers, antennas, leading edges — as supercooled water droplets strike the airframe and freeze.

Context Anchor

Seen in icing discussions, especially when describing rime ice forming on wings, windshields, antennas, or other exposed aircraft surfaces.