What is aviation turbine fuel? Learn how Jet A, Jet A-1 and Jet B differ, what ATF contains and why avgas is not a substitute.
Aviation turbine fuel (ATF) is a petroleum-derived fuel, or a certified blend containing approved synthetic components, formulated for aircraft gas-turbine engines, including turbojets, turbofans, turboprops and turboshafts. Most civil aircraft use kerosene-type Jet A or Jet A-1. It is commonly called jet fuel, but differs chemically and operationally from aviation gasoline (avgas).
Aviation turbine fuel and “jet fuel”
In civil aviation, jet fuel is the everyday name for aviation turbine fuel. The informal name can be misleading because the same fuel also powers turboprops, turbine helicopters and many auxiliary power units.
In our Aviation & Real-World Flying coverage, we use ATF as the umbrella term and Jet A or Jet A-1 when the exact grade matters. Our guide to matching aircraft and engine types with the correct fuel places turbine fuel alongside avgas and diesel-cycle aircraft fuels.
What is aviation turbine fuel made of?
Most ATF is a tightly specified blend of hydrocarbons in the kerosene boiling range, not one pure chemical. It contains varying proportions of paraffins, cycloparaffins and aromatics, refined and blended to meet limits for freezing point, flash point, thermal stability, density, sulphur, combustion quality and contamination.
Approved additives may control static charge, oxidation, corrosion, icing or microbial growth. Their presence and permitted concentration depend on the fuel specification and operator; additives should never be introduced casually. Our detailed comparison of turbine-fuel and avgas composition explains why the two cannot be treated as interchangeable fuels.
Sustainable aviation fuel, or SAF, describes an approved production pathway and its potential lifecycle benefits. Once an eligible synthetic component has been blended, tested and certified to the applicable turbine-fuel specification, the aircraft handles the finished product as aviation turbine fuel. The SAF label alone is not an engine approval.
What are Jet A, Jet A-1 and Jet B?
Jet A and Jet A-1 are the principal kerosene-type civil grades, while Jet B is a more volatile wide-cut fuel intended for unusually cold conditions.
| Grade | Key distinction | Typical use |
|---|---|---|
| Jet A | Minimum flash point of 38°C and maximum freezing point of −40°C | Common in the United States |
| Jet A-1 | Minimum flash point of 38°C and lower maximum freezing point of −47°C | Standard civil grade across much of the world |
| Jet B | Wide-cut gasoline-and-kerosene blend with a maximum freezing point around −50°C; more volatile than Jet A grades | Limited use in very cold regions |
These temperatures are specification limits, not universal aircraft operating limits. The actual batch may test differently, and the aircraft flight manual defines the required fuel-temperature margin.
Military JP designations are separate specifications rather than synonyms for all turbine fuel. JP-8 is broadly based on Jet A-1 with a prescribed additive package, while JP-5 has a higher flash point for naval shipboard handling. The aircraft's approved fuel list always takes precedence over a general similarity between grades.
Why do turbine engines use kerosene fuel?
Kerosene-type fuel provides a useful balance of energy density, controlled volatility, cold-weather performance, lubricity and thermal stability. It can be pumped, metered and atomised reliably while also acting as a heat sink in many aircraft fuel systems.
A gas turbine maintains continuous combustion rather than using spark-timed combustion cycles, so an avgas-style octane rating is not its defining measure. Our explanation of how jet engines meter, atomise and burn fuel shows where ATF enters the propulsion process.
Jet A and Jet A-1 often have a density near 0.80 kg per litre at 15°C, but the exact value changes with composition and temperature. That variation is why commercial fuel planning and aircraft loading use mass rather than assuming that every litre or gallon weighs the same.
Can avgas be used in a turbine engine?
Avgas must not be substituted for aviation turbine fuel unless the exact engine and aircraft approval explicitly lists it as an alternative and all stated restrictions are followed. A limited emergency-fuel approval for one turbine installation does not make avgas generally suitable for turbine aircraft.
Avgas is a more volatile, high-octane fuel designed mainly for spark-ignition piston engines. Putting the wrong fuel into an aircraft can change combustion, lubrication, vapour formation and fuel-control behaviour, with the possibility of engine failure. Conversely, some compression-ignition piston aircraft burn Jet A-type fuel; that does not make their engines turbines.
Fuel handling and calculation
Safe ATF use depends on confirming the specification, preventing contamination and converting delivered volume into the correct mass.
- Verify the grade: Check the aircraft documentation, fuel placard and delivery record. The broad description “jet fuel” is not enough where a particular specification or additive package is required.
- Check for contamination: Free water, sediment, mixed fuel and microbial contamination can block filters or disrupt combustion. A clear-and-bright sample is useful, but appearance alone cannot certify every fuel property.
- Use the supplied density: Fuel may be delivered in litres or gallons while the load sheet uses kilograms or pounds. Use the measured or documented density rather than an avgas conversion factor; our fuel-uplift calculation method explains the conversion.
- Observe fuel-temperature limits: At altitude, compare indicated fuel temperature with the aircraft's approved limit and required margin above the fuel freezing point. Follow the flight manual or checklist rather than assuming −40°C or −47°C is automatically safe.
- Do not improvise additives: Fuel-system icing inhibitor and other additives require the correct product, concentration and mixing procedure.
Flight simulator use
In a flight simulator, select Jet A, Jet A-1 or generic jet fuel for turbine-powered aircraft unless the add-on documentation specifies another grade. Many simulators simplify fuel chemistry and do not model contamination, additives or grade-specific freezing behaviour.
The practical simulator error is confusing volume with mass. A displayed gallon value cannot be copied directly into a field expecting pounds, and a litre value cannot be entered as kilograms. High-fidelity aircraft may also model fuel temperature and require the same aircraft-specific limits used in real-world procedures.