Jet fuel or aviation turbine fuel (ATF, also abbreviated avtur) is a type of aviation fuel designed for use in aircraft powered by gas-turbine engines. It is colorless to straw-colored in appearance. The most commonly used fuels for commercial aviation are Jet A and Jet A-1, which are produced to a standardized international specification.
The only other jet fuel commonly used in civilian turbine-engine powered aviation is Jet B, which is used for its enhanced cold-weather performance.
Jet fuel is a mixture of a variety of hydrocarbons. Because the exact composition of jet fuel varies widely based on petroleum source, it is impossible to define jet fuel as a ratio of specific hydrocarbons. Jet fuel is therefore defined as a performance specification rather than a chemical compound. Furthermore, the range of molecular mass between hydrocarbons (or different carbon numbers) is defined by the requirements for the product, such as the freezing point or smoke point.
Kerosene-type jet fuel (including Jet A and Jet A-1, JP-5, and JP-8) has a carbon number distribution between about 8 and 16 (carbon atoms per molecule); wide-cut or naphtha-type jet fuel (including Jet B and JP-4), between about 5 and 15. Fuel for piston-engine powered aircraft (usually a high-octane gasoline known as avgas) has a high volatility to improve its carburetion characteristics and high autoignition temperature to prevent pre ignition in high compression aircraft engines. Turbine engines (like diesel engines) can operate with a wide range of fuels because fuel is injected into the hot combustion chamber. Jet and gas turbine (turboprop, helicopter) aircraft engines typically use lower cost fuels with higher flash points, which are less flammable and therefore safer to transport and handle.
The first axial compressor jet engine in widespread production and combat service, the Junkers Jumo 004 used on the Messerschmitt Me 262A fighter and the Arado Ar 234B jet recon-bomber, burned either a special synthetic "J2" fuel or diesel fuel. Gasoline was a third option but unattractive due to high fuel consumption. Other fuels used were kerosene or kerosene and gasoline mixtures.
Jet A/A-1
Jet A specification fuel has been used in the United States since the 1950s and is usually not available outside the United States and a few Canadian airports such as Toronto and Vancouver, whereas Jet A-1 is the standard specification fuel used in the rest of the world other than Russia and the CIS members where TS-1 is the most common standard. Both Jet A and Jet A-1 have a flash point higher than 38 °C (100 °F), with an autoignition temperature of 210 °C (410 °F).
Differences between Jet A and Jet A-1
The primary difference is the lower freezing point of A-1:
■ Jet A's is −40 °C (−40 °F)
■ Jet A-1's is −47 °C (−53 °F)
The other difference is the mandatory addition of an anti-static additive to Jet A-1. Jet A trucks, storage tanks, and plumbing that carry Jet A are marked with a black sticker with "Jet A" in white printed on it, adjacent to another black stripe.
Typical physical properties for Jet A and Jet A-1
Jet A-1 fuel must meet:
■ DEF STAN 91-91 (Jet A-1),
■ ASTM specification D1655 (Jet A-1), and
■ ● IATA Guidance Material (Kerosene Type), NATO Code F-35.
Jet A fuel must reach ASTM specification D1655 (Jet A).
Jet B
Jet B is a naphtha-kerosene fuel that is used for its enhanced cold-weather performance. However, Jet B's lighter composition makes it more dangerous to handle. For this reason, it is rarely used, except in very cold climates. A blend of approximately 30% kerosene and 70% gasoline, it is known as wide-cut fuel. It has a very low freezing point of −60 °C (−76 °F), and a low flash point as well. It is primarily used in some military aircraft. It is also used in northern Canada, Alaska, and sometimes Russia, because of its low freezing point.
TS-1
TS-1 is a jet fuel made to Russian standard GOST 10227 for enhanced cold-weather performance. It has somewhat higher volatility than Jet A-1 (flash point is 28 °C (82 °F) minimum). It has a very low freezing point, below −50 °C (−58 °F).