Definition
A cockpit instrument that displays the temperature of the exhaust gases leaving an engine's cylinders. In piston aircraft, it is used primarily as a reference for leaning the fuel/air mixture to achieve the desired engine operating condition. In turbine aircraft, it is a primary engine performance and limit indicator.
Plain English
A gauge that shows how hot the gases coming out of the engine are. Pilots use this reading to set the fuel mixture correctly in piston engines, or to monitor engine health and limits in jets.
Context Anchor
Seen on engine instruments, especially when adjusting the fuel-air mixture during cruise or checking engine operation.
Derivation
“Exhaust” means gases driven out after burning, “gas” is the hot air-like material leaving the engine, and “temperature” means how hot it is. “Indicator” comes from a word meaning “to point out,” which fits because the instrument points out the exhaust temperature to the pilot.
Why Pilots Care
Allows pilots to monitor engine health, adjust fuel mixture for efficiency, and avoid damage from overheating or detonation.
Intuition Check
EGT is not the whole engine temperature. It is specifically the temperature of the exhaust gases after combustion.
Example Sentence 1
After reaching cruise altitude, the pilot leaned the mixture slowly while watching the EGT indicator climb to its peak, then enriched slightly for best-power operation.
Example Sentence 2
A sudden drop on the EGT indicator prompted the pilot to check for a possible cylinder issue.