Definition
Any blockage, narrowing, or obstruction in the path of air moving through the engine compartment, induction system, or cooling passages that reduces the volume of air able to pass through. In the context of the engine compartment, common causes include debris, bird or insect nests, deformed cowling baffles, blocked air filters, or contamination of the induction inlet.
Plain English
Something is blocking or partly blocking the air that needs to flow through the engine area, so less air gets through than should.
Context Anchor
Seen during preflight, engine inspection, and discussions of engine cooling and cowling design.
Why Pilots Care
Unresolved airflow restriction raises cylinder head and oil temperatures, risking engine damage or in-flight shutdown.
Analogy
It is like breathing through a partly covered straw. Air still moves, but not as easily or in the amount needed.
Intuition Check
Do not assume an airflow restriction means air is completely stopped. In aviation use, even a partial blockage can matter if it reduces the air the engine or cooling system needs.
Example Sentence 1
During preflight, the pilot checked the cowling inlets for any airflow restriction such as insect nests or leaves.
Example Sentence 2
An airflow restriction caused by a damaged baffle raised cylinder temperatures on climb-out.