# Jet fuel

**Jet fuel** (aviation turbine fuel) is a refined petroleum product, mostly kerosene, burned in the gas turbine engines of aircraft; it includes kerosene-type jet fuel and naphtha-type jet fuel.<sup>[1](https://www.eia.gov/tools/glossary/index.php?id=jet_fuel)</sup> Chemically it is a complex mixture of C8 to C17 hydrocarbons derived from the kerosene fraction of crude oil distillation and from hydroprocessing of heavier fractions.<sup>[2](https://www.energy.gov/sites/prod/files/2014/04/f14/Roadmap2-08.pdf)</sup> Because aircraft operate at high altitude and carry large fuel loads, jet fuel is governed by tighter specifications than gasoline or diesel, covering energy density, low-temperature flow, and flammability.<sup>[3](https://www.energy.gov/cmei/fuels/sustainable-aviation-fuel-and-us-airport-infrastructure-webinar-text-version)</sup>

| Key fact | Detail |
|---|---|
| Composition | C8–C17 hydrocarbons from the kerosene fraction of petroleum; Jet A contains hundreds of components, about 75%–85% paraffin (straight-chain and cyclic) with the balance almost entirely aromatics<sup>[4](https://www.fire.tc.faa.gov/pdf/tt09-42.pdf)</sup><sup> • </sup><sup>[2](https://www.energy.gov/sites/prod/files/2014/04/f14/Roadmap2-08.pdf)</sup> |
| Main civil grades | Jet A (freeze point −40 °C) and Jet A-1 (−47 °C), both kerosene; Jet B is a wide-cut blend of gasoline and kerosene fractions<sup>[4](https://www.fire.tc.faa.gov/pdf/tt09-42.pdf)</sup><sup> • </sup><sup>[5](https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_65-9A.pdf)</sup> |
| Flash point | Minimum 100 °F (38 °C) for Jet A and Jet A-1; JP-5 is 140 °F (60 °C)<sup>[4](https://www.fire.tc.faa.gov/pdf/tt09-42.pdf)</sup> |
| Density | Average specific gravity at 15 °C: 0.812 for Jet A and Jet A-1; 0.785 for Jet B<sup>[6](https://www.faa.gov/sites/faa.gov/files/regulations_policies/handbooks_manuals/aviation/amt_general_handbook.pdf)</sup> |
| Specification | ASTM D1655 for conventional fuel; a refinery specification defines 30 properties the fuel must meet<sup>[4](https://www.fire.tc.faa.gov/pdf/tt09-42.pdf)</sup><sup> • </sup><sup>[7](https://www.faa.gov/lessons_learned/transport_airplane/accidents/G-YMMM)</sup> |
| Refinery output | U.S. refineries produced 4.41 gallons of kerosene-type jet fuel per 42-gallon barrel of crude oil in 2023<sup>[8](https://www.eia.gov/energyexplained/oil-and-petroleum-products/refining-crude-oil-inputs-and-outputs.php)</sup> |
| Carbon intensity | ICAO baseline for conventional jet fuel is 89 gCO₂e/MJ, of which 74 gCO₂e/MJ is combustion<sup>[9](https://www.icao.int/LCAF)</sup> |

## Grades and history

ASTM D1655, the current commercial standard, lists specifications for three jet fuels: kerosene-based [Jet A](https://www.edgepedia.org/jet-a), Jet A-1, and the wide-cut Jet B.<sup>[4](https://www.fire.tc.faa.gov/pdf/tt09-42.pdf)</sup> Jet A and Jet A-1 differ only in freezing point, −40 °C versus −47 °C; Jet A-1 is made for operation at extremely low temperatures.<sup>[10](https://www.fire.tc.faa.gov/pdf/tn02-79.pdf)</sup><sup> • </sup><sup>[5](https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_65-9A.pdf)</sup> Jet B, essentially the same as the military JP-4, is rarely used today.<sup>[10](https://www.fire.tc.faa.gov/pdf/tn02-79.pdf)</sup>

Military designations run in parallel. JP-4, a wide-cut fuel, was used from 1951 to 1995; JP-5, a high-flash-point (140 °F) kerosene, has been used for Navy carrier aircraft since 1952; JP-8, the kerosene fuel equivalent to Jet A-1 in properties, entered use in 1978 and remains current.<sup>[4](https://www.fire.tc.faa.gov/pdf/tt09-42.pdf)</sup> The U.S. government specified JP-8 in 1990 as a replacement for JP-4, and the Air Force completed the transition by the fall of 1996 to use a less flammable, less hazardous fuel.<sup>[11](https://www.energy.gov/cmei/fuels/full-text-glossary)</sup> Special fuels were also developed for extreme aircraft: JP-6 for the XB-70 in 1956 and JP-7 for the SR-71 in the 1960s.<sup>[4](https://www.fire.tc.faa.gov/pdf/tt09-42.pdf)</sup>

## Properties and why they matter

**Flash point** is the lowest temperature at which a fuel's vapor ignites momentarily when a flame is applied under standardized closed-cup test conditions.<sup>[12](https://www.fire.tc.faa.gov/pdf/ar98-26.pdf)</sup> ASTM D1655 sets a minimum of 100 °F for Jet A, high compared with gasoline at about −40 °F; the flash point of a given batch runs about 10 °F above the lower flammability limit of its vapor.<sup>[4](https://www.fire.tc.faa.gov/pdf/tt09-42.pdf)</sup><sup> • </sup><sup>[13](https://www.faa.gov/media/33281)</sup> A higher flash point means safer handling and less flammable tank vapor, but it constrains refining: raising the flash point specification increases viscosity and degrades aromatics content and smoke point, so a 120 °F (49 °C) flash point specification was estimated to raise average pool viscosity at −20 °C from 5.17 to 5.77 centistokes and aromatics content from 18.6% to 19.0%.<sup>[14](https://www.faa.gov/regulations_policies/rulemaking/committees/documents/media/ECfthwgT1-1231998.pdf)</sup>

**Freezing point** is the temperature at which wax crystals form as fuel cools and completely disappear when it is rewarmed; it is not the temperature at which the fuel becomes solid.<sup>[7](https://www.faa.gov/lessons_learned/transport_airplane/accidents/G-YMMM)</sup><sup> • </sup><sup>[15](https://www.faa.gov/sites/faa.gov/files/2022-11/Polar_Route_Operations.pdf)</sup> As fuel cools, its hydrocarbons solidify progressively, from a few wax crystals to slush to near-solid wax, and the pour point, the lowest temperature at which fuel still flows, is generally about 6 °C below the freezing point.<sup>[15](https://www.faa.gov/sites/faa.gov/files/2022-11/Polar_Route_Operations.pdf)</sup> Fuel is typically manufactured to exceed the specification, so delivered Jet A averages about 3 °C below the −40 °C maximum; measured averages at U.S. airports ranged from −43 °C (Atlanta, Chicago, Dallas–Ft. Worth) to −50 °C (Los Angeles).<sup>[15](https://www.faa.gov/sites/faa.gov/files/2022-11/Polar_Route_Operations.pdf)</sup> Fuel on board the [Boeing 777](https://www.edgepedia.org/boeing-777) involved in the 2008 Heathrow accident (G-YMMM) tested at a freeze point of −57 °C.<sup>[7](https://www.faa.gov/lessons_learned/transport_airplane/accidents/G-YMMM)</sup>

**Water content** is unavoidable. Jet fuel's specific gravity is close to that of water, so introduced water settles slowly, and fuel absorbs water from refueling and from tank vents.<sup>[5](https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_65-9A.pdf)</sup> Water occurs dissolved, entrained, and free; the saturation level in parts per million by volume is roughly the fuel temperature in degrees [Fahrenheit](https://www.edgepedia.org/fahrenheit), so fuel at 50 °F holds about 50 ppmv of dissolved water.<sup>[16](https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20_29C.pdf)</sup> Fuel uploaded to aircraft contains 10 to 30 ppmv of entrained water, which can rise to 70 ppmv in the tank during flight.<sup>[16](https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20_29C.pdf)</sup> Entrained water freezes into snow-like ice crystals between −1 °C and −3 °C, and between −5 °C and −20 °C, the "sticky range" defined in SAE ARP 1401, the ice sticks to fuel system surfaces. The 2008 G-YMMM accident showed that ice accumulated in this range, well above the fuel's freezing point, can break free during a thrust increase and clog the fuel-oil heat exchanger, restricting fuel flow; the finding overturned the earlier assumption that critical icing occurs only near the fuel freezing point.<sup>[7](https://www.faa.gov/lessons_learned/transport_airplane/accidents/G-YMMM)</sup>

## Additives

Jet fuel carries a small package of additives: corrosion and oxidation inhibitors, anti-icing additives (fuel system icing inhibitors, FSII), and a static dissipator additive to control charge buildup during pumping.<sup>[5](https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_65-9A.pdf)</sup><sup> • </sup><sup>[17](https://www.faa.gov/air_traffic/flight_info/aeronav/acf/media/RDs/23-02-381_Fuel_Legend_in_CS.pdf)</sup> The +100 additive improves the thermal stability of kerosene jet fuel and appears in JP-8 supplies.<sup>[17](https://www.faa.gov/air_traffic/flight_info/aeronav/acf/media/RDs/23-02-381_Fuel_Legend_in_CS.pdf)</sup>

## Consumption and emissions

The United States consumes roughly 26 billion gallons of jet fuel per year.<sup>[3](https://www.energy.gov/cmei/fuels/sustainable-aviation-fuel-and-us-airport-infrastructure-webinar-text-version)</sup> [Combustion](https://www.edgepedia.org/combustion) of jet fuel produces CO₂ and water vapor in proportion to fuel burned and to the fuel's carbon and hydrogen content; the average hydrogen content of jet fuel is 13.84%.<sup>[18](https://ntrs.nasa.gov/api/citations/19940033096/downloads/19940033096.pdf)</sup> EIA's emission factor for jet fuel is 70.88 million metric tons of CO₂ per quadrillion Btu at full combustion.<sup>[19](https://www.eia.gov/outlooks/aeo/assumptions/pdf/0554%282012%29.pdf)</sup> Under ICAO's CORSIA scheme, the baseline life-cycle value for conventional jet fuel is 89 gCO₂e/MJ, of which combustion accounts for 74 gCO₂e/MJ and the well-to-tank supply chain about 15 gCO₂e/MJ.<sup>[9](https://www.icao.int/LCAF)</sup><sup> • </sup><sup>[20](https://www.icao.int/sites/default/files/Meetings/a42/Documents/WP/wp_131_en.pdf)</sup>

## Sustainable aviation fuel

Sustainable aviation fuel (SAF) is jet fuel made from non-petroleum feedstocks and blended into conventional fuel. [ASTM D7566](https://www.edgepedia.org/astm-d7566) governs synthesized hydrocarbon fuels and sets blending limits by pathway: Fischer-Tropsch synthetic paraffinic kerosene (FT-SPK, approved 2009) at 50%, hydroprocessed esters and fatty acids (HEFA-SPK, 2011) at 50%, alcohol-to-jet (ATJ-SPK, 2016) at 50%, catalytic hydrothermolysis (CHJ, 2020) at 50%, and algae-derived HC-HEFA-SPK (2020) at 10%; ASTM D1655 also allows co-processing of biomass feedstocks at a refinery up to 5%.<sup>[21](https://afdc.energy.gov/fuels/sustainable-aviation-fuel)</sup> SAF qualifies for emissions credit under CORSIA based on its life-cycle value in gCO₂e/MJ, and fossil-based fuel can be certified as a Lower Carbon Aviation Fuel if it achieves at least a 10% reduction against the 89 gCO₂e/MJ baseline, a maximum of 80.1 gCO₂e/MJ.<sup>[22](https://www.icao.int/CORSIA/fuels-lifecycle)</sup><sup> • </sup><sup>[9](https://www.icao.int/LCAF)</sup> In ICAO's 2050 scenario analysis, residual aviation CO₂ emissions fall from about 1,940 Mt with fossil jet only to 1,120 Mt with SAF averaging a 60% life-cycle emission reduction, and to about 330 Mt with 90% SAF reduction plus hydrogen aircraft.<sup>[23](https://www.icao.int/sites/default/files/environmental-protection/Documents/EnvironmentalReports/2025/Final-ENV-REPORT.pdf)</sup>

## References

1. [Jet fuel, EIA Glossary](https://www.eia.gov/tools/glossary/index.php?id=jet_fuel)
2. [Breaking the Chemical and Engineering Barriers to Lignocellulosic Biofuels (Roadmap 2007), U.S. Department of Energy](https://www.energy.gov/sites/prod/files/2014/04/f14/Roadmap2-08.pdf)
3. [Sustainable Aviation Fuel and U.S. Airport Infrastructure Webinar, U.S. Department of Energy](https://www.energy.gov/cmei/fuels/sustainable-aviation-fuel-and-us-airport-infrastructure-webinar-text-version)
4. [Aviation Turbine Fuel Flammability, FAA Technical Note TT09-42](https://www.fire.tc.faa.gov/pdf/tt09-42.pdf)
5. [AC 65-9A, Airframe and Powerplant Mechanics General Handbook, FAA](https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_65-9A.pdf)
6. [Aviation Maintenance Technician General Handbook (FAA-H-8083-30A)](https://www.faa.gov/sites/faa.gov/files/regulations_policies/handbooks_manuals/aviation/amt_general_handbook.pdf)
7. [Boeing 777-236ER (G-YMMM) Lessons Learned, FAA](https://www.faa.gov/lessons_learned/transport_airplane/accidents/G-YMMM)
8. [Refining crude oil: inputs and outputs, U.S. Energy Information Administration](https://www.eia.gov/energyexplained/oil-and-petroleum-products/refining-crude-oil-inputs-and-outputs.php)
9. [Lower Carbon Aviation Fuels, ICAO](https://www.icao.int/LCAF)
10. [Fuel Tank Flammability and Inerting, FAA Technical Note TN02-79](https://www.fire.tc.faa.gov/pdf/tn02-79.pdf)
11. [Full Text Glossary, U.S. Department of Energy](https://www.energy.gov/cmei/fuels/full-text-glossary)
12. [Inerting of General Aviation Aircraft Fuel Tanks (AR98-26), FAA](https://www.fire.tc.faa.gov/pdf/ar98-26.pdf)
13. [Prevention of Fuel Tank Explosions, Fuel Tank Harmonization Working Group, FAA](https://www.faa.gov/media/33281)
14. [Fuel Tank Inerting for Transport Airplanes, Fuel Tank Harmonization Working Group, FAA](https://www.faa.gov/regulations_policies/rulemaking/committees/documents/media/ECfthwgT1-1231998.pdf)
15. [Polar Route Operations, Boeing AERO Magazine (FAA archive)](https://www.faa.gov/sites/faa.gov/files/2022-11/Polar_Route_Operations.pdf)
16. [AC 20-29C, Approval and Use of Fuel System Icing Inhibitors, FAA](https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20_29C.pdf)
17. [Fuel Legend in the Chart Supplement, FAA](https://www.faa.gov/air_traffic/flight_info/aeronav/acf/media/RDs/23-02-381_Fuel_Legend_in_CS.pdf)
18. [Water Vapor Emissions, NASA Technical Reports](https://ntrs.nasa.gov/api/citations/19940033096/downloads/19940033096.pdf)
19. [Carbon dioxide emission factors, EIA Annual Energy Outlook assumptions](https://www.eia.gov/outlooks/aeo/assumptions/pdf/0554%282012%29.pdf)
20. [Lower Carbon Aviation Fuel working paper A42-WP/131, ICAO](https://www.icao.int/sites/default/files/Meetings/a42/Documents/WP/wp_131_en.pdf)
21. [Sustainable Aviation Fuel, Alternative Fuels Data Center, U.S. Department of Energy](https://afdc.energy.gov/fuels/sustainable-aviation-fuel)
22. [SAF Lifecycle, ICAO CORSIA](https://www.icao.int/CORSIA/fuels-lifecycle)
23. [ICAO Environmental Report 2025, Climate Change Mitigation](https://www.icao.int/sites/default/files/environmental-protection/Documents/EnvironmentalReports/2025/Final-ENV-REPORT.pdf)

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*Topic: Encyclopedia › Technology and the built world › Energy technology › Fuels and conversion technology › Titles In to W › Titles I to Re*

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