Definition
The maximum quantity of usable fuel an aircraft can carry on board, expressed in gallons or pounds, as established by the manufacturer and limited by tank size, structural weight limits, and any installed auxiliary tanks.
Plain English
How much fuel the aircraft is able to hold when fully filled, within the limits set for safe loading.
Context Anchor
Seen when using climb and cruise performance charts to plan whether the aircraft has enough fuel for the climb, cruise, reserve, and any expected delays.
Derivation
Fuel comes from an old word for material burned to produce heat or power. Capacity comes from a Latin word meaning “to take or hold.” Together, the phrase points to how much fuel the aircraft can hold and take along for flight.
Why Pilots Care
It sets the upper limit on fuel load, which directly affects takeoff weight, climb performance, and how far the aircraft can fly.
Intuition Check
Do not read “capacity” as the amount you must carry on every flight. Here it means the usable amount the aircraft can carry; the actual fuel loaded may be less depending on the trip and loading limits.
Example Sentence 1
With a fuel carrying capacity of 56 gallons, the aircraft had plenty of range for the cross-country, but the pilot loaded only 40 gallons to stay under maximum gross weight with four people on board.
Example Sentence 2
Knowing the fuel carrying capacity helped the pilot interpret the cruise chart correctly when the tanks would be only partially filled.