Definition
The amount of useful work or distance an engine produces for a given quantity of fuel burned, typically expressed in pounds or gallons of fuel per hour, per nautical mile, or per unit of power output. In turbocharged engine operation, fuel economy is influenced by mixture setting, manifold pressure, RPM, and altitude.
Plain English
How efficiently the engine turns fuel into flight — how much fuel it uses to go a certain distance or produce a certain amount of power.
Context Anchor
Seen in turbocharging discussions when comparing engine power, altitude, fuel-air mixture settings, and how much fuel the engine burns.
Derivation
From 'fuel' (the substance burned for energy) and 'economy,' from the Greek oikonomia meaning 'management of a household' — later broadened to mean efficient use of resources. In aviation it means efficient use of fuel.
Why Pilots Care
Better fuel economy extends range, reduces operating costs, and improves safety margins on long flights.
Intuition Check
Fuel economy does not mean simply using less fuel at any cost. It means using fuel efficiently while still keeping the engine operating correctly and producing the power the flight requires.
Example Sentence 1
At higher altitudes, the turbocharger maintains power while the thinner air improves fuel economy, giving the airplane longer range.
Example Sentence 2
Operating the turbocharged engine at higher altitude often yields better fuel economy because of lower drag.