Cylinder Head Temperature Gauge

A temperature measuring probe can either be located in the cylinder head or in the spark plug washer. It operates using the thermo-couple principle, previously described for the exhaust gas temperature gauge. The probe is fitted to the hottest cylinder, which is normally one of the rear cylinders.

The CHT is a good indication to the pilot when the critical point of detonation is occurring or is about to be approached. Keep in mind that the indication is only reflecting that one cylinder where it may appear normal, when another cylinder not been measured may be suffering detonation and overheating.

The pilot can control CHT by varying airspeed or power through changes in manifold pressure or engine rpm and mixture control. The CHT gauge changes slowly which requires the pilot to monitor it over time. A rapidly fluctuating CHT reading would indicate that the gauge is faulty.