The auxiliary fuel tanks are ______ type.

• A. Bladder type
• B. Rigid type
• C. Tubular type
• D. Sealed type

Answer: (A)

Auxiliary fuel tanks are bladder-type because they use a flexible, fuel-compatible membrane that sits inside a structural shell to form the actual reservoir. This setup lets the tank fit into awkward or limited spaces, like wing cavities or centerline bays, without requiring heavy, rigid metal shapes and extensive structural reinforcement. The bladder’s flexibility provides weight savings and easier installation or replacement, since you can deploy or remove the bladder without redesigning the surrounding structure. The fuel is contained by the bladder itself, which means you get a compact, adaptable tank that can shape to the available space while keeping weight down compared with rigid tanks. Compared with other types, bladder tanks excel in fitting irregular geometries and simplifying installation, which is why they’re the typical choice for auxiliary fuel capacity in many aircraft.