Definition
A reduction in the temperature of a surface or airflow caused by the rapid expansion or low-pressure conditions produced as air moves over an aircraft. In icing contexts, it refers to the local cooling that occurs on airframe surfaces where airflow accelerates and pressure drops, allowing supercooled water droplets to freeze on impact even when the ambient air temperature is slightly above freezing.
Plain English
When air speeds up and spreads out as it flows around the aircraft, it gets a little colder in places. That extra cooling can drop a wing or other surface below freezing, so water droplets striking it can turn into ice.
Context Anchor
Seen in structural icing discussions, especially when explaining why ice may form on aircraft surfaces in visible moisture near the freezing point.
Derivation
Aerodynamic comes from the Greek 'aero' (air) and 'dynamis' (force or power), meaning related to air in motion. Pairing it with 'cooling' points to a temperature drop caused by the way air behaves as it flows, not by outside weather.
Why Pilots Care
It explains why ice can form on wings when the ambient temperature is above freezing, affecting decisions about flight in visible moisture.
Grounding Statement
Picture air speeding up over the top of the wing on a damp, near-freezing day: that local cooling can be enough to freeze water droplets the moment they touch the surface.
Intuition Check
Do not assume aerodynamic cooling means the outside air itself is getting colder. It means the aircraft surface can become colder because of the airflow around it.
Example Sentence 1
The instructor explained that aerodynamic cooling can let ice form on the wings even when the outside air temperature is a little above freezing.
Example Sentence 2
Structural icing formed on the leading edges because of aerodynamic cooling even though the reported surface temperature was above zero.