Definition
The temperatures measured at or near the cylinder heads of a piston engine, indicating how hot the upper portion of each cylinder is running during operation. Cylinder head temperature (CHT) is monitored to ensure the engine stays within its manufacturer-approved operating range, particularly during high-power phases such as climb, when cooling airflow is reduced and combustion heat is high.
Plain English
How hot the top of each engine cylinder is getting. Pilots watch this number to make sure the engine isn't overheating, especially during a climb when the engine is working hard and air isn't flowing through it as quickly.
Context Anchor
You see this during engine monitoring, especially during climbs, when the engine is working hard and cooling airflow may be reduced.
Derivation
Cylinder comes from the Greek 'kylindros,' meaning a roller or rolling body — describing the round, tube-shaped combustion chambers in a piston engine. 'Head' refers to the top end of the cylinder where the spark plugs and valves sit. So cylinder head temperature is simply the heat reading taken at the top of each combustion chamber.
Why Pilots Care
Excessive cylinder head temperatures can damage the engine, so pilots monitor them closely and adjust power or airspeed as needed.
Intuition Check
Do not read “head” as the pilot’s head or as the whole engine. Here, “cylinder head” means the metal top section of an engine cylinder, where heat can build up during operation.
Example Sentence 1
During a prolonged climb on a hot day, the pilot lowered the nose slightly to increase airspeed and bring cylinder head temperatures back into the green arc.
Example Sentence 2
After reducing power slightly, the cylinder head temperatures stabilized within the normal operating range.