Definition
Interturbine Temperature (ITT) is the temperature of the gas stream measured between the turbine stages of a turbine engine. It is sensed by thermocouples positioned in the gas path between (or just aft of) the turbine wheels and is used as the primary indication of how hot the engine's hot section is operating. ITT is a limiting parameter — exceeding published ITT limits during start, acceleration, or steady-state operation can cause turbine damage and requires a maintenance inspection.
Plain English
ITT is a temperature reading taken inside the engine, in the gas flow between the turbine wheels. It tells the pilot how hot the engine is running internally and must be kept within the limits printed in the manual.
Context Anchor
Seen on turbine-engine instrument panels, especially during engine start, takeoff, climb, and power changes.
Derivation
Inter' comes from Latin meaning 'between.' So 'interturbine' literally means 'between the turbines' — a direct description of where the temperature is measured.
Why Pilots Care
Helps pilots monitor engine health and avoid overheating that could damage the engine.
Grounding Statement
When more fuel is burned, the gases driving the turbine usually get hotter, and ITT is the cockpit indication of that heat at the measured point.
Intuition Check
ITT is not outside-air temperature and not cabin temperature. It is an engine temperature measured inside the turbine section.
Example Sentence 1
During engine start, the pilot watched the ITT climb rapidly and was ready to cut the fuel if it approached the start limit.
Example Sentence 2
Rising ITT readings led the crew to reduce power and investigate the engine.