Definition
Engine instruments that display the operating temperature of one or more cylinder heads in a piston engine, using a sensor (typically a thermocouple) attached to or threaded into the cylinder head. The reading helps the pilot manage engine cooling by adjusting power, mixture, airspeed, or cowl flaps to keep temperatures within manufacturer limits.
Plain English
Gauges that show how hot the engine cylinders are getting, so the pilot can keep the engine from running too hot.
Context Anchor
In a steep spiral or other prolonged descent, a pilot may check these gauges while managing power and airspeed to keep engine temperatures within the airplane's normal operating range.
Derivation
Cylinder comes from an old Greek word for a roller or rounded shape. Head, in engine use, means the closed top part of the cylinder. Gauge comes from an old word meaning to measure, which fits because these instruments measure engine heat at that specific part.
Why Pilots Care
Monitoring cylinder head temperature helps prevent engine overheating and damage during high-power operations or when airflow for cooling is limited.
Grounding Statement
During a long low-power descending turn, cooling air may flow over the engine while power changes still affect heat, and these gauges show what is actually happening.
Intuition Check
Do not read head as the nose or front of the engine. In cylinder head temperature gauges, head means the closed top part of each engine cylinder, where much of the heat is concentrated.
Example Sentence 1
During the steep spiral, the pilot periodically added power and monitored the cylinder head temperature gauges to prevent excessive cooling.
Example Sentence 2
If the cylinder head temperature gauges show rising temperatures, the pilot can reduce power or increase airspeed to restore proper cooling.