Definition
The components of an aircraft engine that measure and deliver the correct amount of fuel to be mixed with air before combustion. In a piston engine this is either a carburetor or a fuel injection system, along with the controls (throttle and mixture) that regulate how much fuel reaches the cylinders.
Plain English
The part of the engine that controls how much fuel goes in, so the engine gets the right fuel-to-air mix to run properly.
Context Anchor
You encounter this term in engine operation discussions, especially during takeoff and climb when the engine must produce steady, full power.
Derivation
To 'meter' something means to measure it out in controlled amounts, like a water meter measuring flow. The fuel metering system measures out fuel in precise quantities matched to the air entering the engine.
Why Pilots Care
Correct fuel metering prevents power loss, roughness, or engine damage when full power is required for takeoff and climb.
Intuition Check
Do not think of “metering” as simply reading a gauge. Here, it means measuring out and delivering the correct amount of fuel to the engine.
Example Sentence 1
On takeoff from a high-elevation airport, the pilot leaned the mixture to allow the fuel metering system to deliver the correct fuel-air ratio for the thinner air.
Example Sentence 2
As the airplane climbs and air density decreases, the pilot leans the mixture to keep the fuel metering system matched to the reduced airflow.