Everything about Aviation Fuel totally explained
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 fuels available for aircraft are kinds of
petroleum spirit used in engines with spark plugs for example
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.
The
Convention on International Civil Aviation, which came into effect in
1947, exempted air fuels from tax.
Australia and the
USA oppose a worldwide levy on aviation fuel, but a number of other countries have expressed interest.
Avgas
Avgas is a
high-octane fuel used for
aircraft and
racing cars. The term
Avgas is a
portmanteau for
aviation gasoline, as distinguished from
mogas (motor gasoline), which is the everyday
petroleum spirit used in
cars. Avgas is typically used in aircraft that use
reciprocating piston or
Wankel engines.
Jet fuel
Jet fuel is a clear to straw colored fuel, based on either an
unleaded paraffin oil (
Jet A-1), or a
naphtha-
kerosene blend (
Jet B). It is similar to
diesel fuel, and can be used in either
compression ignition engines or
turbine engines.
In use
Aviation fuel is often dispensed from a tanker or
bowser which is driven up to parked
aeroplanes and
helicopters. Some airports have pumps similar to
filling stations that aircraft must taxi up to. Some 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
car fuelling — one or more fuel 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's only one attachment point, fuel distribution between tanks is either automated or it's controlled from a control panel at the fuelling point or in the cockpit. As well, a
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 millimetres (49 millimetres in the
USA). The aperture on fuel tanks of piston-engined aircraft can't be greater than 60 millimetres in diameter. Jet Fuel is clear to straw in colour, and is dispensed from a special nozzle called a "J spout" that has a rectangular opening larger than 60 millimetres 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 fuelling port too small for the J spout and thus require a smaller nozzle to be installed in order to be refuelled efficiently.
Energy content
The
net energy content for aviation fuels depends on their composition. Some typical values are:
(External Link
)
- Avgas, 43.7 MJ/kg or 31.0 MJ/L
- Wide-cut jet fuel, 43.5 MJ/kg or 33.2 MJ/L
- Kerosene type jet fuel, 43.8 MJ/kg or 35.1 MJ/L
Chemical composition
Aviation fuels consist of blends of over a thousand chemicals, primarily
Hydrocarbons (
paraffins,
olefins,
naphthenes, and
aromatics) as well as additives such as
antioxidants and metal deactivators, and impurities. Principal components include
n-octane and
isooctane. Like other fuels, blends of Aviation fuel used in piston engined aircraft are often described by their
Octane rating.
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 isn't 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. In addition,
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.
Many airlines now require that safety belts be left unfastened should passengers be aboard when refuelling happens.
Further Information
Get more info on 'Aviation Fuel'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://aviation_fuel.totallyexplained.com">Aviation fuel Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |