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Jet A-1 (AVT/Avtur) Fuel
Jet fuel, also known as aviation turbine fuel (ATF) or avtur, is an aviation fuel designed for aircraft with gas-turbine engines. It appears colorless to straw-colored. The most common fuels for commercial aviation are Jet A and Jet A-1, which adhere to a standardized international specification. Jet B is the other jet fuel widely used in civilian turbine-engine powered aviation, chosen for its superior cold-weather performance.
Jet fuel comprises various hydrocarbons, and its exact composition varies greatly depending on the petroleum source. Therefore, jet fuel is defined by a performance specification rather than by a specific chemical composition. The range of molecular mass among the hydrocarbons, or the number of carbon atoms per molecule, is determined by product requirements like the freezing point or smoke point. Kerosene-type jet fuels, including Jet A and Jet A-1, JP-5, and JP-8, have a carbon number distribution from about 8 to 16; wide-cut or naphtha-type jet fuels, including Jet B and JP-4, range from about 5 to 15.
Standards
Since the conclusion of World War II, most jet fuels have been kerosene-based. The initial standards for jet fuels in both Britain and America were established post-war. The UK’s standards evolved from kerosene lamp usage—referred to as paraffin—while the US standards originated from aviation gasoline practices. Over time, specifications such as the minimum freezing point were modified to optimize performance and fuel availability. Extremely low freezing points limit fuel availability, and higher flash point products, necessary for aircraft carriers, are costlier to produce. ASTM International sets the standards for civilian fuel types in the US, while the U.S. Department of Defense does so for military applications. The British Ministry of Defence sets standards for both civil and military jet fuels. To ensure interoperability, British and American military standards are somewhat aligned.
Jet A fuel has been utilized in the United States since the 1950s and is typically not available outside the U.S., except at a few Canadian airports like Toronto and Vancouver. Conversely, Jet A-1 is the standard fuel specification used globally, including the Chinese RP-3 standard, which closely resembles Jet A-1, except in Russia and CIS countries where TS-1 is more common. Both Jet A and Jet A-1 fuels have a flash point above 38°C (100°F) and 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 A-1 | Jet A | |
|---|---|---|
| Flash point | 38 °C (100 °F) | |
| Autoignition temperature | 210 °C (410 °F) | |
| Freezing point | −47 °C (−53 °F) | −40 °C (−40 °F) |
| Max adiabatic burn temperature | 2,230 °C (4,050 °F) open air burn temperature: 1,030 °C (1,890 °F) | |
| Density at 15 °C (59 °F) | 0.804 kg/L (6.71 lb/US gal) | 0.820 kg/L (6.84 lb/US gal) |
| Specific energy | 43.15 MJ/kg (11.99 kWh/kg) | 43.02 MJ/kg (11.95 kWh/kg) |
| Energy density | 34.7 MJ/L (9.6 kWh/L) | 35.3 MJ/L (9.8 kWh/L) |