Aircraft fuel tanks

Aircraft fuel tanks are a major component of aircraft fuel systems. They can be classified into internal or external tanks and further classified by method of construction or intended use. Safety aspects of aircraft fuel tanks were examined during the investigation of the 1996 TWA Flight 800 in-flight explosion accident.

Integral tanks are areas inside the aircraft structure that have been sealed to allow fuel storage. An example of this type is the "wet wing" commonly used in larger aircraft. Since these tanks are part of the aircraft structure, they cannot be removed for service or inspection. Inspection panels must be provided to allow internal inspection, repair, and overall servicing of the tank. Most large transport aircraft use this system, storing fuel in the wings, fuselage, and empennage of the aircraft.

Rigid removable tanks are installed in a compartment designed to accommodate the tank. They are typically of metal, plastic or fibreglass construction, and may be removed for inspection, replacement, or repair. The aircraft does not rely on the tank for structural integrity. These tanks are commonly found in smaller general aviation aircraft, such as the Cessna 172. Combat aircraft and helicopters generally use self-sealing fuel tanks.

Bladder tanks, bag tanks or fuel cells, are reinforced rubberised bags installed in a section of aircraft structure designed to accommodate fuel. The bladder is rolled up and installed into the compartment through the fuel filler neck or access panel, and is secured by means of snap fasteners or cord and loops inside the compartment. Many high-performance light aircraft, helicopters and some smaller turboprop aircraft use bladder tanks.

Many aircraft designs feature fixed tip tanks mounted at the end of each wing. The weight of the tanks and fuel counteract wing bending loads during manoeuvres and reduce fatigue on the spar structure.

Conformal fuel tanks (CFTs) or 'Fast Packs' are additional fuel tanks fitted closely to the profile of an aircraft which extend either the range or endurance of the aircraft, with a reduced aerodynamic penalty compared to external drop tanks.

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