Fuel System
Fuel system in aircraft is designed to deliver uniform flow of clean fuel from the tank to the propulsion system of the aircraft without any interruption to power system during continuous flight at high altitude, during all approved maneuvers. Each fuel tank is equipped with internal fuel pumps, valves and plumbing to feed fuel to the engine to produce thrust.
Fuel system consist multiple fuel tanks located in the wing or fuselage base on aircraft design, intended use and as well as age aircraft determine which fuel tank to be installed. The tanks are made of non corrosive materials that are non reactive aviation fuel. Aluminium alloy are more commonly used in modern aircraft fuel tank of its light weight and corrosive resistant, Synthetic rubber coated type fuel cells are also used.
In high wing aircraft there is no need of any pumps to feed the fuel. Gravity propels the fuel from tank to the engine. In lighter Aircraft and low wing aircraft fuel tanks are located inside the wing. Have filler opening at the top of the wing through which fuel can be filled and drains in the bottom by which any moisture can be removed, to drain fuel sample for inspection. Electrical Pump been used to pass the fuel from the tank to the Carburetor, and pressure gauge will be attached to the pump show weather the pumps are working properly. Vent (Duct) placed to equalise the internal pressure. Fuel selector valveare used to avoid imbalance fuel flow and allow to choose from which tank the fuel should flow to the Engine. Before the fuel enters the engine fuel will passes through the Strainer where the water and other contaminated particles are removed to avoid improper quality fuel to flow leads to Failure of Fuel system.
Common fuel system issues
Pressurization of Fuel Tank
During maneuvering, rolling and yawing motion of the aircraft Centrifugal force will be created due to which pressure acts on fuel tank. During design fuel tank will undergo analyse applying different pressure load at pitch yaw roll motion to calculate natural frequency and resonance which may leads to the vibration of the fuel Tank which are more effective.
Failure of Fuel pump
Pumps have automatic bypass valves. If one valve fails other pumps will continue normal flow to pass the failed pump. A failure pump can causes several of problems. Fuel pump is a non serviceable part means it needs to be replaced.
Imbalance fuel flow
On flight the usage and the movement of the fuel in the fuel tank keeps changing which would change center of gravity of the aircraft. Many air craft have pump to pass the fuel from one tank in the wing to another to balance level equally on both as not to get heavier on onside. This happens because of unequal usage of fuel by the engines. Imbalance fuel flow affects the stability of the aircraft during flight.
