Definition
A form of structural ice that combines the characteristics of both clear ice and rime ice, forming when supercooled water droplets of varying sizes — or a mix of droplets and ice crystals — strike the airframe at temperatures that allow some droplets to freeze instantly while others spread before freezing. The result is a rough, opaque-and-glassy ice accumulation with irregular shapes that can build quickly on leading edges.
Plain English
Ice on the aircraft that is part smooth and clear, part rough and milky, all mixed together. It forms when the water droplets in the cloud are of different sizes, so some freeze instantly and others spread out before freezing.
Context Anchor
Seen in structural icing discussions when identifying the kind of ice forming on wings, propellers, windshields, or other outside aircraft surfaces.
Derivation
Mixed comes from the Latin miscere, meaning “to mix.” Rime is an old word for frost. The phrase helps because it means the aircraft is not carrying just one clean type of ice; it has a combination of clear ice and frost-like rime ice.
Why Pilots Care
Mixed ice often creates the greatest loss of lift and increase in drag because the irregular rime portion disrupts airflow while the clear portion adds significant weight.
Grounding Statement
Picture ice on a wing that is not all glassy and not all frosty, but a patchy combination of both.
Intuition Check
“Clear” does not mean the weather is clear here; it means one part of the ice may be hard and see-through. “Mixed” means both clear-type and rime-type ice are present on the aircraft.
Example Sentence 1
The pilot reported mixed clear and rime icing on the wings while climbing through a layer of stratus near the freezing level.
Example Sentence 2
Precautionary landing was chosen after mixed clear and rime accumulation began to affect control response during the approach.