Basic Fuel System & Components

Fuel System?

Introduction

It’s important to know every systems inside an aircraft. “You know your?Aircraft!”. Which will definitely makes you a better Aviator. One among the important system to know about is Fuel System, & here we discuss about the Fuel on a most widely used training Aircraft Cessna 172. Knowing & Understanding these systems will make your training more interesting.

Components of Fuel Systems.

Fuel Tank

a)Integrated Fuel Tanks

b)Tank Vents

1. Integrated Fuel Tanks

In this case fuel tank is integrated with airframe. Ie Wings are Carrying Fuel. Which will also help to maintain CG by balancing the fuel weight symmetrically.

b) Tank Vents

Fuel Tanks are provided with vents in-order to prevent vacuum buildup on fuel tanks thereby not disturbing the flow of fuel .

3 vents are provided, 2 of them provided on each fuel caps. And one vent is provided like a protruded tube from the tank.( This Outside vent also act as fuel drain in case of fuel expansion due to higher temperature on a warm sunny day.)

2. Fuel Selector?

It has 3 different selection LEFT/RIGHT/BOTH.

These selector help to switch?the fuel source accordingly. T/OFF & Landing with the fuel selector valve not in the BOTH position is strictly Prohibited.

3. Reservoir

Helps to provide constant fuel supply(1 Gal min maintained ) even during unusual pitch or attitude which may cause disrupt the fuel flow.

4. Auxiliary Fuel Pump

High wing aircrafts are based on gravity fed fuel system. Even though electrically driven fuel pump are used thereby these can act as a redundancy in the system which can be used during an emergency Situation. Another main use of this electrically driven pump is?to prime the engine during a cold Start.

5. Fuel Shutoff Valve

This is an emergency shutoff valve. In case of an engine fire or to prevent leaks or existing fire hazard.

6. Strainer

Fuel Strainer Quick drain valves are located under wings and fuselage. It is provided to check the quality of fuel. To make sure that fuel is free from any type of contaminants.

Will make sure the fuel is good by identifying the color of fuel and foreign particles like dirt/Water particles inside the fuel.

7.Engine Driven Fuel Pump.

This is the main Fuel Pump Used to Pump the fuel and maintain the fuel pressure. Which is responsible for pumping the fuel in coordination with the Fuel Control Unit.

8.Fuel/Air control unit

Senses the amount of air goes to the engine accordingly distribute the fuel flow to the fuel Distributor. Which is metered fuel amount to the fuel distributor.

9.Fuel Distributor.

Where the metered fuel is accumulated and injected to the intake manifold through the fuel nozzle or injector. Which basically act as a single platform to provide uninterrupted fuel supply to the distinctive fuel injectors. Something like a Common Rail Direct injection on Automobiles.

10. Fuel injectors?

These are the tiny ports which injects and delivers the fuel to the intake manifold ( Just prior to the inlet valve) at high pressure. Which causing atomized fuel spray and will be easily mixed with air particles very efficiently.