Definition
Atmospheric conditions in which ice can form on an aircraft in flight. These conditions exist when visible moisture (such as clouds, rain, drizzle, snow, or fog with low visibility) is present and the outside air temperature is at or below freezing, typically considered +5°C or colder when supercooled droplets may be present.
Plain English
Weather conditions that can cause ice to build up on the airplane. You need two things at the same time: moisture you can see in the air, and air that is cold enough to freeze it.
Context Anchor
Seen in discussions of anti-icing and deicing equipment, preflight weather decisions, and whether an airplane is approved to fly where ice may form.
Derivation
“Icing” comes from “ice” plus “-ing,” meaning ice forming or being added. In aviation, it points to ice forming on the airplane, not just ice already present on the ground.
Why Pilots Care
Icing reduces lift, increases drag, and can block sensors or control surfaces, leading to handling problems or loss of control.
Grounding Statement
Picture flying through a cold cloud where tiny water drops hit the airplane and freeze onto its surfaces.
Intuition Check
Do not assume icing conditions mean ice must already be visible on the airplane. The term can mean the weather is capable of creating ice, even before a pilot sees buildup.
Example Sentence 1
The pilot reviewed the forecast and decided to delay departure because icing conditions were reported along the planned route.
Example Sentence 2
When encountering icing conditions, the pilot turned on the deice boots to remove ice from the wing leading edges.