Definition
Turbine gas temperature (TGT) is the temperature of the hot exhaust gases as they pass through or near the turbine section of a turbine engine. It is measured by thermocouples positioned in the gas path and displayed in the cockpit as a primary engine limit. TGT is one of several names manufacturers use for this measurement, depending on exactly where in the gas path the probes sit; related names include EGT (exhaust gas temperature), ITT (interstage turbine temperature), and TIT (turbine inlet temperature).
Plain English
TGT is a gauge that tells the pilot how hot the gases flowing through the turbine are. If those gases get too hot, the turbine blades can be damaged, so the pilot watches this number to keep the engine within safe limits.
Context Anchor
Seen on turbine-engine instrument panels and in engine operating procedures, especially during engine start, takeoff, climb, and high-power operation.
Derivation
‘Turbine’ comes from the Latin turbo, meaning a spinning or whirling thing. The turbine is the spinning wheel driven by hot gases inside the engine, and TGT is simply the temperature of the gases at that wheel.
Why Pilots Care
Excessive TGT readings warn of overheating that can damage turbine blades and reduce engine life.
Grounding Statement
When more fuel is burned to make more power, the gas going through the turbine gets hotter, and the TGT reading rises.
Intuition Check
TGT is not the temperature of the air outside the aircraft or the cabin air. It is an internal engine temperature reading for the hot gas in the turbine area.
Example Sentence 1
During engine start, the pilot watched the TGT closely to make sure it stayed below the start limit.
Example Sentence 2
A sudden TGT spike after landing prompted an engine inspection before the next flight.