Definition
Atmospheric conditions in which structural icing on an aircraft is possible. These conditions exist when visible moisture (clouds, rain, drizzle, fog, or wet snow) is present and the outside air temperature is at or below a defined threshold, commonly +5 °C (41 °F) or colder, depending on the aircraft's certification and operating rules.
Plain English
Weather conditions where ice could form on the aircraft. This means there is visible moisture in the air and the temperature is cold enough for that moisture to freeze on the airframe.
Context Anchor
You will see this term in weather briefings, aircraft operating limitations, flight planning, and discussions about whether a route is safe for an aircraft that is not approved for flight in icing.
Derivation
"Potential" comes from the Latin potentia, meaning "power" or "possibility." Here it carries the sense of "possible but not yet happening" -- the conditions for icing exist, even if ice has not actually formed yet.
Why Pilots Care
Ice changes the shape of wings and control surfaces, reducing lift, increasing drag, and raising the risk of loss of control.
Grounding Statement
If the airplane is flying through visible moisture and the temperature is freezing or near freezing, the situation should be treated as one where icing could occur.
Intuition Check
Potential does not mean imaginary or harmless here. It means the conditions are capable of producing aircraft icing, even if no ice has been seen yet.
Example Sentence 1
The crew turned on engine anti-ice when entering potential icing conditions during the climb through cloud at +3 °C.
Example Sentence 2
The pilot decided to remain in visual conditions to avoid the reported potential icing conditions.