Aircraft fuel system

1. R e f u e l i n g A n d D e f u e l i n g

2. TABLE OF CONTENTS
• Types of Aviation fuel
• The specifications and Characteristics
• Fuel identification
• Refueling
• Refueling procedure
• Defueling
• Safety precautions

3. TYPES OF AVIATION FUEL
Mainly two types fuel used in aviation
 AVGAS => Aviation gasoline
 AVTUR => Aviation Turbine
 AVTAG => Aviation Turbine Gasoline

4. • The specification of an ideal fuel for either a gas turbine
engine or a piston engine would include the following main
requirements :
Ease of flow under all operating conditions.
Complete combustion under all conditions.
High calorific.
Purity
Non-corrosive.
No damage to the engine from combustion by-products.
Low fire hazard.
Ease of engine starting lubricity.
THE SPECIFICATIONS AND CHARACTERISTICS

5. CHARACTERISTICS
o Volatility (describe changes from liquid into a vapor)
o Vapor Lock (is a condition in which AVGAS vaporizes
in the fuel line or other components between the fuel
tank and the carburetor)
 Gasoline Vapor Pressure : 5.5  7 PSI at 100F
 Jet A Vapor Pressure 0.1 PSI at 100F
 Jet B Vapor Pressure 2  3 PSI at 100F

6. Detonation : is the rapid, uncontrolled explosion of fuel due to
high pressure and temperature in the combustion chamber.
Aviation fuels are refined and blended to avoid detonation …

7. FUEL
IDENTIFICATION

9. REFUELING
Refueling can be considered in two
categories
• Open orifice fuel system
• Pressure refueling system

10. REFUELING
PROCEDURE
• Aircraft may have the fuel pumped directly into the tank
from over the wing or from a single point source under the
wing
• Befor driving the fuel truck to the a/c be sure that the
sumps have been drained and that the sight gages show
that the fuel is bright and clear
• The fire extinguisher must be placed and they must be fully
charged
• After stopping the truck in front the a/c and parallel to the
wing Set the parking brakes on the truck and connect the
static bonding wire between the truck and the aircraft

11. • Put the mat over the wing so the fuel hozel will not scratch
the finish.
• Connect the static bonding wire between the nozzele and
the a/c
• Then remobe the fuel tank cover –Remove the dust cap
from the nozzle and when inserting the nozzle into the tank
be sure that the end of the nozzle does not contact the
bottom of the tank

12. MOST OF THE LARGE AIRPORTS THAT SERVICE TRANSPORT A/C WITH GREAT
AMOUNT OF FUEL HAVE UNDRERGROUND STORAGE TANKS AND BURIED FUEL
LINES THAT ALLOW THE A/C TO BE FUELED WITHOUT CARRY THE FUEL TO THE
AIRCRAFT

13. DEFUELING
Power Defueling
The bulk of the fuel in an aircraft’s tanks should be removed by suction. A
pump/engine assembly or the pump of a refueler provides the power. The
aircraft can be defueled either with a defueling tube or by using a piece of
salvaged suction hose.
Defueling tube. A defueling tube is fitted onto the suction hose. The tube is
inserted into the tank and most of the fuel is pumped out.
Suction hose. A piece of 1- or 1 1/2-inch salvaged suction hose may also be used
to defuel an aircraft. The end that will be inserted into the tank is cut at an angle
so that the reinforcing wire is cut only once. The cut end of the reinforcing wire is
also rounded to keep it from damaging the fuel tank. The hose is inserted into the
tank and most of the fuel is pumped out.
Gravity Defueling
Gravity defueling is the process of draining the tanks by opening the drain valves
or petcocks of the aircraft fuel system. It is a slow and dangerous process. Some
suitable container must be placed under the valves to catch the fuel. Except in
an emergency, this method should be used only to complete the draining of the
aircraft fuel system after the bulk of the fuel has been removed by a pump.

14. SAFETY PRECAUTIONS
• Allowed to handle fuel: Only personnel trained in Safe operation of equipment and fuels they
use Operation of emergency controls Procedures to be followed in an emergency.
• Fire Extinguisher Placement Required on aircraft fuel servicing vehicles or carts Each aircraft
fuel servicing tank vehicle must have two listed fire extinguishers - ABC multipurpose dry
chemical fire extinguishers (ammonium phosphate).
• Put the correct grade of fuel .
• Be sure that the fuel truck is bounded to the a/c.
• Be sure that the fuel nozzle is properly bounded to the structure .
• Wipe up spilled fuel or flood it with water , do not sweep spilled fuel with a dry broom.
• Be sure there are no open fires in the vicinity of the fueling or defueling operation.
• Be sure that the radio or radar are not used during fueling or defueling and that no electrical
equipements is turned on or off exept equipements needed for the operation
• Ensure pressure delivery rate followed as manufacturer specification