AIRCRAFT FUEL TANK

An airplane fuel tank is a meticulously designed, secure container integrated into an aircraft to safely store and deliver aviation fuel. In contemporary commercial aviation, the wings of the aircraft serve as the main fuel tanks, a design approach referred to as integral tanks or "wet wings". This versatile design significantly reduces weight and structurally balances the aerodynamic lift forces exerted on the wings during flight.

Primary Types of Aircraft Fuel Tanks

• Integral Tanks (Wet Wings): These are fully sealed, unused hollow spaces within the wing and fuselage panels. They are the most prevalent type in commercial aircraft like the Airbus A320 due to their ability to maximize volume and reduce airframe weight.

• Bladder Tanks: Made from reinforced, flexible rubberized bags, these can be rolled, packed, and deployed inside a confined compartment. They are commonly used in smaller turboprops, high-performance light aircraft, and helicopters.

• Rigid Removable Tanks: Separate, solid metal containers typically made from aluminum alloy or stainless steel. They are securely riveted and seam-welded to prevent leaks, making them favored for vintage aircraft and light models like the Diamond DA20.

• External/Drop Tanks: Auxiliary aerodynamic pods attached beneath the fuselage or wings. These are prevalent on military fighter jets to extend range and can be jettisoned in emergencies or combat.

  
  

  Core Anatomy & Internal Components

  The internal structure of an aviation fuel tank includes several complex sub-systems:

  • Baffles and Check Valves: Internal partition walls with one-way valves that prevent fuel from sloshing outward during steep banks, climbs, or heavy turbulence.

  • Fuel Booster Pumps: Submerged electric or hydraulic centrifugal pumps that deliver fuel directly to the cross-feed lines and engines under constant pressure, preventing vapor lock.

  • Venting and Surge Systems: Dedicated side compartments (surge tanks) that capture overflow and maintain atmospheric pressure inside the tanks as fuel is used.

  • Capacitance Probes: Highly accurate electronic level sensors that continuously measure the mass and volume of the fuel using changing electrical capacitance values.

  • Inerting Systems: Advanced safety mechanisms that remove oxygen from the empty air volume inside the tank and replace it with non-combustible nitrogen gas, reducing fire risks from sparks or static electricity.

Typical Structural Distribution

In a modern commercial airliner, the full capacity is strategically distributed across multiple locations:

1. Main Wing Tanks: Situated on both the left and right wings to supply their respective engines.

2. Center Wing Box Tank: Located in the fuselage belly between the wings; its fuel is used first to maintain optimal structural balance.

3. Trim Tanks: Positioned in the rear tail (horizontal stabilizer) to dynamically adjust the aircraft's center of gravity during flight.