Definition
A fuel tank formed by sealing off a portion of the aircraft structure itself — typically a section of the wing — so that the structure becomes the tank. The skin, ribs, and spars serve as the walls of the tank, with all seams and fasteners sealed against fuel leakage. Often called a wet wing when the tank is built into the wing.
Plain English
Instead of installing a separate fuel container inside the aircraft, part of the aircraft's own structure is sealed up and used as the fuel tank.
Context Anchor
Seen in aircraft systems, maintenance, and fuel-system descriptions, especially for aircraft with fuel stored inside the wings.
Derivation
Integral comes from the Latin integer, meaning whole or complete. An integral fuel tank is built as part of the whole structure rather than added in as a separate piece.
Why Pilots Care
Integral tanks save weight and space but require careful inspection for leaks and corrosion since any damage affects both structure and fuel containment.
Analogy
It is like using a sealed part of a boat’s hull as a water container instead of placing a separate jug inside the boat.
Intuition Check
Integral does not mean a math calculation here. It means the tank is built into the aircraft structure and is part of it.
Example Sentence 1
The Cessna 210's wing is an integral fuel tank, so any fuel stains along the lower wing skin should be noted during preflight.
Example Sentence 2
During preflight, check the integral fuel tanks for signs of leakage around the seams and rivets.