Aviation fuel
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Aviation Fuel is a specialised 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.
Aviation fuel is typically divided into two categories: Avgas, which is used in piston-engined aircraft, and jet fuel, which is used in jet-engined aircraft.
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 |
Avgas
See Main Article for Avgas.
Jet Fuel
See Main Article for Jet fuel.
In use
Aviation fuel is often dispensed from a truck or bowser which is driven up to parked airplanes and helicopters. Less commonly, 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.
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.
See also
External links
- History of military jet fuels
- Aviation Fuels (by Chevron)
- Jet Fuel Truth - a site & forum dedicated to price monitoring and transparency of profit taking by FBO's, which is short for Fixed Base Operator.
- Fillup Flyer - one of the first online (1992!) sites dedicated to helping pilots get better fuel deals.fr:Carburant aviation