Definition
A turbine engine component that meters the flow of fuel to the combustion chambers based on inputs such as power lever position, engine speed, compressor inlet pressure, and ambient conditions, ensuring the engine receives the correct amount of fuel for the demanded power without exceeding operating limits.
Plain English
The device on a turbine engine that decides how much fuel to send to the burners. It reads what the pilot is asking for and what the engine is currently doing, then delivers the right amount of fuel to match.
Context Anchor
Seen in turbine-engine operation, especially when discussing how a split-shaft or free-turbine engine responds to power-lever movement.
Derivation
Plainly named after its job: it controls the fuel. The word 'unit' simply means a self-contained assembly, signalling that this is one packaged device rather than a loose collection of valves.
Why Pilots Care
Correct operation prevents flameout, compressor stall, overtemperature, and rough power response during rapid throttle changes or altitude shifts.
Intuition Check
Do not think of it as just an on/off fuel valve. A fuel control unit continuously controls how much fuel flows to the engine.
Example Sentence 1
When the pilot advanced the power lever, the fuel control unit increased fuel flow to spool the engine up to takeoff power.
Example Sentence 2
During a descent in a free-turbine helicopter, the fuel control unit automatically reduces fuel delivery to prevent overtemperature as load decreases.