Definition
A measure of how much useful work or distance an airplane gets from a given quantity of fuel, typically expressed as miles per gallon, nautical miles per pound of fuel, or specific range. Higher fuel efficiency means more distance flown, or more time aloft, for each unit of fuel burned.
Plain English
How far the airplane can go on a given amount of fuel. The more distance you get from each gallon, the more fuel-efficient the airplane is.
Context Anchor
Pilots encounter fuel efficiency when planning a flight, choosing a power setting, leaning the mixture, estimating fuel burn, and deciding whether the airplane has enough fuel reserve.
Derivation
“Fuel” comes from an old word meaning material used for a fire. “Efficiency” comes from a word meaning to bring about or produce a result. Together, the term points to how much flying result the airplane produces from the fuel it burns.
Why Pilots Care
It determines how far the aircraft can travel on available fuel, affects operating costs, and influences decisions about reserves and alternate airports.
Analogy
It is similar to miles per gallon in a car, but in an airplane the best choice may depend on wind, altitude, weight, and the power setting you choose.
Intuition Check
Fuel efficiency does not simply mean burning the least fuel per hour. It means getting the best useful flight result for the fuel burned.
Example Sentence 1
Leaning the mixture at cruise altitude improved fuel efficiency, giving them an extra 30 nautical miles of range.
Example Sentence 2
Improved fuel efficiency let the airplane complete the trip with more reserve fuel than planned.