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

TABLE OF CONTENTS

• Types of Aviat ion fuel

• The speci f icat ions and Character i s t ics

• Fuel identif ication

• Refuel ing

• Refuel ing procedure

• Defuel ing

• Safety precaut ions

TYPES OF AVIATION FUEL

Mainly two types fuel used in aviation

AVGAS => Aviation gasoline

AVTUR => Aviation Turbine

AVTAG => Aviation Turbine Gasoline

• 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

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

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 …

FUELIDENTIFICATION

REFUELING

Refueling can be considered in two categories

• Open orifice fuel system

• Pressure refueling system

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

• 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

MOST OF THE LARGE AIRPORTS THAT SERVICE TRANSPORT A/C WITH GREATAMOUNT 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

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.

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