Definition
The proportion of fuel to air, by weight, delivered into an engine's combustion section for burning. In gas turbine engines, this mixture is formed continuously inside the combustion chamber, where atomized fuel is sprayed into a stream of compressed air and ignited.
Plain English
How much fuel is mixed with how much air before it burns inside the engine. Get the ratio right and the engine runs cleanly; get it wrong and the engine runs poorly or not at all.
Context Anchor
Seen in gas turbine engine discussions about starting, combustion, acceleration, and engine power.
Why Pilots Care
The right fuel/air mixture keeps the engine running efficiently and prevents damage from burning too much or too little fuel.
Intuition Check
Do not assume this means the pilot is manually leaning a mixture control as in many small piston airplanes. In this turbine-engine context, it means the burnable blend created inside the engine by the engine’s fuel and air systems.
Example Sentence 1
The fuel control unit on a turbine engine automatically adjusts the fuel/air mixture as altitude and throttle position change.
Example Sentence 2
A too-rich fuel/air mixture can cause excessive turbine temperatures during start.