Definition
Cockpit instruments that display the quantity of usable fuel remaining in each fuel tank, typically marked in gallons or pounds. They are required to be installed and operative for flight, but are known to be most accurate only when reading empty.
Plain English
The dials or digital readouts in the cockpit that show how much fuel is left in each tank.
Context Anchor
Seen during preflight checks, before engine start, and during flight when the pilot monitors fuel remaining.
Derivation
Fuel comes from an older word meaning material used for a fire or source of power. Gauge originally meant a standard or tool for measuring. Together, fuel gauges are measuring instruments for the airplane’s power source.
Why Pilots Care
Fuel quantity must be known accurately for safe flight planning; gauges are checked to catch leaks, sensor faults, or incorrect fueling.
Analogy
Fuel gauges are like a car’s fuel gauge, but in an airplane you treat them more carefully because running low on fuel has much more serious consequences and the indication may not tell the whole story.
Intuition Check
Do not assume fuel gauges prove the tanks are actually full. They show an indication in the cockpit; the pilot still verifies fuel quantity during preflight as much as practical.
Example Sentence 1
During preflight, the pilot checked the fuel gauges in the cockpit and then climbed up to visually confirm the fuel levels in each tank.
Example Sentence 2
In flight the pilot monitored the fuel gauges to ensure sufficient quantity remained for the planned route.