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[[Image:Jet a1 truck refueling dsc04316.jpg|thumb|right|At some airports, underground fuel pipes allow refueling without the need for tank trucks. Trucks carry the necessary hoses and pumping equipment, but no fuel.]]
'''Aviation fuels''' are [[petroleum]]-based [[fuel]]s, or petroleum and synthetic fuel blends, used to power [[aircraft]]. They have more stringent requirements than fuels used for ground use, such as [[heating]] and [[road transport]], and contain additives to enhance or maintain properties important to fuel performance or handling. They are [[kerosene]]-based ([[JP-8]] and [[Jet A-1]]) for gas turbine-powered aircraft. Piston-engined aircraft use [[leaded gasoline]] and those with diesel engines may use [[jet fuel]] (kerosene).<ref name=chevron>{{Cite web|url=https://www.skybrary.aero/bookshelf/books/2478.pdf|title = SKYbrary Aviation Safety}}</ref> By 2012, all aircraft operated by the [[United States Air Force|U.S. Air Force]] had been certified to use a 50-50 blend of kerosene and synthetic fuel derived from coal or natural gas as a way of stabilizing the cost of fuel.<ref>{{Cite web|url=https://www.airforcemag.com/article/0712fuel/|title=The Air Force's Fuel Problem}}</ref>
As aviation moves into the renewables era, [[hydrogen-powered aircraft]] might enter common use. Hydrogen fuel cells do not produce {{CO2}} or other emissions (besides water). However, hydrogen combustion does produce {{NOx}} emissions. Cryogenic hydrogen can be used as a liquid at temperatures below 20 K. Gaseous hydrogen involves pressurized tanks at 250–350 bar.<ref name=Kramer2020>{{cite journal ▼
|doi=10.1063/PT.3.4632▼
|title=Hydrogen-powered aircraft may be getting a lift ▼
|last1=Kramer ▼
|first1=David▼
|author-link=▼
|date=1 December 2020 ▼
|journal=[[Physics Today]]▼
|volume=73 ▼
|issue=12 ▼
|pages=27–29 ▼
|bibcode=2020PhT....73l..27K ▼
|doi-access=free}}</ref> With materials available in the 2020s, the mass of tanks strong enough to withstand this kind of high pressure will greatly outweigh the hydrogen fuel itself, largely negating the weight to energy advantage of hydrogen fuel over hydrocarbon fuels. Hydrogen has a severe volumetric disadvantage relative to hydrocarbon fuels, but future [[blended wing body]] aircraft designs might be able to accommodate this extra volume without greatly expanding the [[wetted area]].▼
==Types of aviation fuel==
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==== Jet fuel ====
{{main|Jet fuel}}
[[File:Mig-29 refueling.jpg|thumb|Ground fueling of a [[MIG-29|MiG-29]] from a [[Ural-4320|URAL tanker]] (2011)
'''Jet fuel''' is a clear to straw-colored fuel, based on either an [[unleaded]] [[kerosene]] (Jet A-1), or a [[naphtha]]-[[kerosene]] blend (Jet B). Similar to [[diesel fuel]], it can be used in either [[Diesel engine|compression ignition engine]]s or [[Gas turbine|turbine engine]]s.<ref name=chevron/>
Jet-A powers modern commercial airliners and is a mix of extremely refined kerosene and burns at temperatures at or above {{convert|49|C}}. Kerosene-based fuel has a much higher flash point than gasoline-based fuel, meaning that it requires significantly higher temperature to ignite. It is a high-quality fuel; if it fails the purity and other quality tests for use on jet aircraft, it is sold to ground-based users with less demanding requirements, such as railroads.<ref>{{cite web |last=U.S. Centennial of Flight Commission |title=Aviation Fuel |url=http://www.centennialofflight.gov/essay/Evolution_of_Technology/fuel/Tech21.htm |access-date=10 May 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120420064213/http://www.centennialofflight.gov/essay/Evolution_of_Technology/fuel/Tech21.htm |archive-date=20 April 2012 }}</ref>
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==== Biofuels ====
Alternatives to conventional fossil-based aviation fuels, new fuels made via the [[biomass to liquid]] method (like [[sustainable aviation fuel]]) and [[Aviation biofuel|certain straight vegetable oils]] can also be used.<ref>{{cite journal |pmc = 5801801|year = 2018|last1 = Wang|first1 = M.|title = Highly efficient conversion of plant oil to bio-aviation fuel and valuable chemicals by combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreating|journal = Biotechnology for Biofuels|volume = 11|pages = 30|last2 = Chen|first2 = M.|last3 = Fang|first3 = Y.|last4 = Tan|first4 = T.|pmid = 29445419|doi = 10.1186/s13068-018-1020-4 | doi-access=free }}</ref>
Fuels such as
==== Compressed natural gas and liquified natural gas ====
{{Main|Natural_gas#Transportation}}
[[Compressed natural gas]] (CNG) and [[Liquefied natural gas#Transportation|liquified natural gas]] (LNG) are fuel feedstocks that aircraft may use in the future. Studies have been done on the feasibility of using natural gas<ref>{{cite web|url=http://lae.mit.edu/aircraft-design/|title=Aircraft Design - MIT Laboratory for Aviation and the Environment|access-date=27 December 2016|url-status=dead|archive-url=https://web.archive.org/web/20161230163921/http://lae.mit.edu/aircraft-design/|archive-date=2016-12-30}}</ref> and include the "SUGAR Freeze" aircraft under NASA's N+4 Advanced Concept Development program (made by Boeing's Subsonic Ultra Green Aircraft Research (SUGAR) team). The [[Tupolev Tu-155]] was an alternative fuel testbed which was fuelled on LNG.<ref>{{cite web|url=http://midwestenergynews.com/2013/08/26/could-natural-gas-fuel-commercial-flights-of-the-future/|title=Could natural gas fuel commercial flights of the future?|last=EnergyWire|access-date=2016-12-27|url-status=live|archive-url=https://web.archive.org/web/20161105204049/http://midwestenergynews.com/2013/08/26/could-natural-gas-fuel-commercial-flights-of-the-future/|archive-date=2016-11-05}}</ref> The low [[specific energy]] of natural gas even in liquid form compared to conventional fuels gives it a distinct disadvantage for flight applications.{{citation needed|date=March 2018}}
==== Liquid hydrogen ====
{{Main|Hydrogen-powered aircraft}}
[[Hydrogen]] can be used largely free of [[carbon emission]]s, if it is produced with power from [[renewable energy]] like [[wind power|wind]] and [[solar power]].
Some development of technology for [[hydrogen-powered aircraft]] started after the millennium and gained track since about 2020, but as of 2022 was still far away from outright aircraft product development.
▲
▲ |doi=10.1063/PT.3.4632
▲ |title=Hydrogen-powered aircraft may be getting a lift
▲ |last1=Kramer
▲ |first1=David
▲ |author-link=
▲ |date=1 December 2020
▲ |journal=[[Physics Today]]
▲|volume=73
▲ |issue=12
▲ |pages=27–29
▲ |bibcode=2020PhT....73l..27K
▲ |doi-access=free}}</ref> With materials available in the 2020s, the mass of tanks strong enough to withstand this kind of high pressure will greatly outweigh the hydrogen fuel itself, largely negating the weight to energy advantage of hydrogen fuel over hydrocarbon fuels. Hydrogen has a severe volumetric disadvantage relative to hydrocarbon fuels, but future [[blended wing body]] aircraft designs might be able to accommodate this extra volume without greatly expanding the [[wetted area]].
Even if finally practical, the industry timeline for adopting hydrogen is fairly lengthy. Alternatives to conventional aviation fuel available in the near term include [[aviation biofuel]] and synthetically created fuel (aka "e-jet").<ref>{{Cite web|last=Trakimavicius|first=Lukas|date=December 2023|title=Mission Net-Zero: Charting the Path for E-fuels in the Military|url=https://www.enseccoe.org/data/public/uploads/2023/11/d5_mission-net-zero-charting-the-path-for-e-fuels-in-the-military-by-lukas-trakimavicius.pdf |publisher=NATO Energy Security Centre of Excellence}}</ref> These fuels are collectively referred to as "Sustainable Aviation Fuel" (SAF).
==Production of aviation fuel==
The production of aviation fuel falls into two categories: fuel suitable for [[Gas turbine|turbine engine]]s and fuel suitable for spark-ignition piston engines. There are international specifications for each.
[[Jet fuel]] is a gas turbine fuel used in propeller and jet aircraft and helicopters. It has a low [[viscosity]] at low temperature, has limited ranges of density and [[calorific value]], burns cleanly, and remains chemically stable when heated to high temperature.<ref>{{cite web|author=Air BP |title=Avgas vs Jet Fuel |url=http://www.bp.com/sectiongenericarticle.do?categoryId=4503818&contentId=57639 |access-date=10 May 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120425054146/http://www.bp.com/sectiongenericarticle.do?categoryId=4503818&contentId=57639 |archive-date=25 April 2012 }}</ref>
[[Aviation gasoline]], often referred to as "avgas" or 100-LL (low-lead), is a highly refined form of [[gasoline]] for aircraft, with an emphasis on purity, [[engine knock|anti-knock]] characteristics and minimization of [[spark plug]] fouling. Avgas must meet performance guidelines for both the rich mixture condition required for take-off power settings and the leaner mixtures used during cruise to reduce fuel consumption. Aviation fuel can be used as CNG fuel.
Avgas is sold in much lower volume than jet fuel, but to many more individual aircraft operators; whereas jet fuel is sold in high volume to large aircraft operators, such as airlines and
==Energy content==
The [[net energy content]] for aviation fuels depends on their composition. Some typical values are:<ref>[[Air BP]]. [http://www.bp.com/liveassets/bp_internet/aviation/air_bp/STAGING/local_assets/downloads_pdfs/a/air_bp_products_handbook_04004_1.pdf BP Products handbook] {{webarchive|url=https://web.archive.org/web/20110608075828/http://www.bp.com/liveassets/bp_internet/aviation/air_bp/STAGING/local_assets/downloads_pdfs/a/air_bp_products_handbook_04004_1.pdf |date=2011-06-08 }}. Retrieved 2008-09-13</ref>
*BP Avgas 80, [[Orders of magnitude (energy)#1E6|44.65]]{{Broken anchor|date=2024-05-26|bot=User:Cewbot/log/20201008/configuration|target_link=Orders of magnitude (energy)#1E6|reason= The anchor (1E6) [[Special:Diff/383867230|has been deleted]].}} [[Joule|MJ]]/kg, density at 15 °C is 690 kg/[[cubic metre|m<sup>3</sup>]] ({{Round|44.65*690/1000|2}} MJ/litre).
*Kerosene type BP Jet A-1, 43.15 MJ/kg, density at 15 °C is 804 kg/m<sup>3</sup> ({{Round|43.15*804/1000|2}} MJ/litre).
*Kerosene type BP Jet TS-1 (for lower temperatures), 43.2 MJ/kg, density at 15 °C is 787 kg/m<sup>3</sup> ({{Round|43.2*787/1000|2}} MJ/litre).
==Density==
In performance calculations, airliner manufacturers use a density of jet fuel around {{#expr:(6.75+6.7+6.7+6.77+6.55+6.7)/6round1}} lb/
Specific cases are:
* [[Bombardier Aerospace]]: The Challenger Multi-role Aircraft is a special mission variant of the Bombardier Challenger 650 business jet platform. Bombardier bases performance on the use of fuel with an average lower heating value of 18,550
* [[Embraer]]: In its airport planning manual for the E195 uses an adopted fuel density of {{cvt|0.811|kg/
== Chemical composition ==
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==Tax==
The [[Convention on International Civil Aviation]] (ICAO) (Chicago 1944, Article 24) exempts air fuels already loaded onto an aircraft on landing (and which remain on the aircraft) from import taxes.<ref name="HoC Library">{{cite web
|author=House of Commons Library
|title=Taxing aviation fuel. Standard Note SN00523 (2012)
|url=http://www.parliament.uk/briefing-papers/SN00523.pdf
|page=3, note 11
|access-date=4 Nov 2016}}</ref> Bi-lateral [[air services agreement]]s govern the tax exemption of aviation fuels.<ref>{{Cite web |title=Fuel Service and Aviation Fuel |url=https://www.jetex.com/fuel-service/ |access-date=2023-03-03 |website=FBO Networks, Ground Handling, Trip Planning, Premium Jet Fuel |language=en-US}}</ref>{{cn|date=November 2022}} In the course of an EU initiative, many of these agreements have been modified to allow taxation.{{cn|date=November
A worry is that a local aviation fuel tax would cause increased [[tankering]], where airlines carry extra fuel from low tax jurisdictions. This extra weight increases fuel burn, thus a local fuel tax could potentially increase overall fuel consumption.<ref name="HoC Library"/> To avoid increased tankering, a worldwide aviation fuel tax has been proposed.{{By whom|date=November 2022}} Australia and the United States oppose a worldwide During a debate in the [[UK Parliament]], the forgone tax income due to the exemption of tax on aviation fuel was estimated at £10 billion annually.<ref>{{cite web|last=Lucas|first=Caroline|title=Does the government subsidise airlines by £10 billion?|url=http://fullfact.org/factchecks/airline_industry_subsidies_green_taxes-3256|work=2012|date=24 January 2012|publisher=Factcheck|access-date=27 August 2013|url-status=live|archive-url=https://web.archive.org/web/20130817012751/http://fullfact.org/factchecks/airline_industry_subsidies_green_taxes-3256|archive-date=17 August 2013}}</ref> The planned inclusion of international aviation into the [[European Union Emission Trading Scheme]] in 2014 has been called an == Certification ==
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== In use ==
[[File:AvFuelHoustonTXBush.JPG|thumb|Aviation fuel storage tanks at [[George Bush Intercontinental Airport]], [[Houston]],
Aviation fuel generally arrives at the airport via pipeline systems, such as the [[Central Europe Pipeline System|CEPS]]. It is then pumped over and dispensed from a tanker or [[bowser (aviation)|bowser]]. The fuel is then driven up to parked [[aircraft]] and [[helicopter]]s. Some airports have pumps similar to [[filling station]]s to which aircraft must taxi. Some airports have permanent piping to parking areas for large aircraft.
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===Underwing===
<!--[[Single point (disambiguation)]] links here for aircraft single-point refueling. -->
[[File:Single-Point_Fueling.jpg|thumb|right|Most [[widebody aircraft]] use a double single-point.]]
Underwing fueling, also called single-point refueling or pressure refueling where not dependent on gravity, is used on larger aircraft and for jet fuel exclusively.
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|archive-url = https://web.archive.org/web/20120525061351/http://www.csgnetwork.com/avgas.html
|archive-date = 25 May 2012
}}</ref><ref>{{cite web
|last=Shell.com
|title=AvGas Grades and Specifications
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Jet fuel is clear to straw-colored, and is dispensed from a special nozzle called a J spout or duckbill that has a rectangular opening larger than 60 mm diagonally, 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.{{citation needed|date=December 2018}}
===Forecasting demand===
In recent years, fuel markets have become increasingly volatile. This, along with rapidly changing airline schedules and the desire to not carry excess fuel on board aircraft, has increased the importance of demand forecasting. In March 2022, Austin's Austin-Bergstrom International Airport came close to running out of fuel, potentially stranding aircraft.<ref>{{Cite web |last=Best |first=Paul |date=March 28, 2022 |title=Austin airport sends out fuel shortage alert amid 'increased flight activity' |website=[[Fox Business]] |url=https://www.foxbusiness.com/economy/austin-texas-airport-fuel-shortage-alert-increased-flight-activity |access-date=November 7, 2022}}</ref> Common forecasting techniques include tracking airline schedules and routes, expected distance flown, ground procedures, [[fuel efficiency]] of each aircraft and the impact of environmental factors like weather and temperature.<ref>{{Cite web |title=Navigate aviation fuel demand volatility with effective forecasting |url=https://www.cirium.com/thoughtcloud/navigate-aviation-fuel-demand-volatility-with-effective-forecasting/ |access-date=2022-11-07 |website=Cirium |language=en-US}}</ref>
== Safety precautions ==
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* [https://web.archive.org/web/20121018042938/http://www.bp.com/sectiongenericarticle.do?categoryId=4503664&contentId=57733 History of jet fuels] (by [[BP|AirBP]])
* [https://web.archive.org/web/20090704014521/http://www.chevron.com/products/ourfuels/prodserv/fuels/documents/aviation_fuels.pdf Aviation Fuels Technical Review] (by [[Chevron Corporation|Chevron Global Aviation]])
{{DEFAULTSORT:Aviation Fuel}}
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