Aviation fuel

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An aviation fuel truck.
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An aviation fuel truck.
On some airports, underground fuel pipes allow refueling without the need for tank trucks. Trucks just carry the necessary hoses and pressure apparatus, but no fuel.
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On some airports, underground fuel pipes allow refueling without the need for tank trucks. Trucks just carry the necessary hoses and pressure apparatus, but no fuel.

Aviation Fuel is a specialized type of petroleum-based fuel used to power aircraft; it is generally of a higher quality than fuels used in less critical applications such as heating or road transport, and often contains additives to reduce the risk of icing or explosion due to high temperatures, amongst other properties.

Most Aviation Fuel available for aircraft are kinds of gasoline used in engines with spark plugs i.e. piston engines and Wankel rotaries or fuel for jet turbine engines which is also used in diesel aircraft engines. Alcohol, alcohol mixtures and other alternative fuels may be used experimentally but are not generally available.

Avgas is sold in much lower volumes, but to many more individual aircraft, whereas Jet Fuel is sold in high volumes to large aircraft operated typically by airlines, military and large corporate aircraft.

At a 1944 international convention in Chicago taxes on air fuels were exempted. Australia and the USA oppose a worldwide levy on aviation fuel, but a number of other countries have expressed interest.

Contents

[edit] Avgas

See Main Article for Avgas.

[edit] Jet Fuel

See Main Article for Jet fuel.

[edit] In use

Aviation fuel is often dispensed from a truck or bowser which is driven up to parked airplanes and helicopters. Some airports have pumps similar to filling stations that aircraft must taxi up to. Some extremely large airports also have permanent piping to parking areas for large aircraft.

Regardless of the method, aviation fuel is transferred to an aircraft via one of two methods: overwing and underwing. Overwing fuelling is used on smaller planes, helicopters, and all piston-engine aircraft. Overwing fuelling is similar to automobile fuelling — one or more gas ports are opened and fuel is pumped in with a conventional pump. Underwing fuelling, also called single-point, is used on larger aircraft and for jet fuel exclusively. For single-point fuelling, a high-pressure hose is attached and fuel is pumped in at up to 50 PSI. Since there is only one attachment point, fuel distribution between tanks is either automated or it is controlled from a control panel at the fueling point or in the cockpit. As well, dead man's switch is used to control fuel flow.

Because of the danger of confusing the fuel types, a number of precautions are taken to distinguish between AvGas and Jet Fuel beyond clearly marking all containers, vehicles, and piping. AvGas is treated with either a red, green, or blue dye, and is dispensed from nozzles with a diameter of 40 millimeters (49 millimeters in the USA). The aperture on fuel tanks of piston-engined aircraft cannot be greater than 60 millimeters in diameter. Jet Fuel is clear to straw in color, and is dispensed from a special nozzle called a "J spout" that has a rectangular opening larger than 60 millimeters in diameter so as not to fit into AvGas ports. However, some jet and turbine aircraft, such as some models of the Astar helicopter, have a fueling port too small for the J spout and thus require a smaller nozzle to be installed in order to be refuelled efficiently.

[edit] Safety Precautions

Any fuelling operation can be very dangerous, and aviation fuelling has a number of unique characteristics which must be accommodated. As an aircraft flies through the air, it can accumulate a charge of static electricity. If this is not dissipated before fuelling, an electric arc can occur which may ignite fuel vapours. To prevent this, aircraft are electrically bonded to the fuelling apparatus before fuelling begins, and are not disconnected until fuelling is complete. Some regions require that the aircraft and/or fuel truck be grounded as well.

Aviation fuel can cause severe environmental damage, and all fuelling vehicles must carry equipment to control fuel spills. As well, fire extinguishers must be present at any fuelling operation, and airport firefighting forces are specially trained and equipped to handle aviation fuel fires and spills. Aviation fuel must be checked daily and before every flight for contaminants such as water or dirt.

[edit] See also

[edit] External links

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