Aviation fuels

Aviation fuels are fuels that are used to power aircraft. The main types include aviation turbine fuel (Jet A-1), kerosene-gasoline mixture (Jet B), aviation gasoline (AvGas), Blended (or 'finished') SAF and Neat (or 'unfinished') SAF - also called Sustainable Aviation Fuels (SAF).

Definition
Aviation fuels comprise various fuels that are used in aviation to supply aircraft with energy. The main categories include kerosene-based fuels such as Jet A-1 as well as blended and neat SAF, which are aviation fuel categories produced from different feedstocks, including renewable resources.

Background / Origin
Aviation fuels are categorized in detail into different types. Jet fuel, primarily Jet A-1, is used in civil aviation in turbine engines, especially in jet engines and turboprops. The fuel is a refined, light petroleum and is subject to strict international quality standards in order to meet the high requirements of aviation.

Jet B is a special blend of gasoline and kerosene used in military aviation. Due to its higher flammability and lower freezing point, this fuel is preferred in cold regions.

Aviation gasoline, also known as AvGas, is mainly used in older piston engines of sports and private aircraft. Its use is limited due to the high production costs and the associated quality requirements. More recent developments include blended (or 'finished') SAF, which is being developed as an alternative to conventional aviation fuels and is already being used in tests.

SAF, or Sustainable Aviation Fuels, are produced from renewable or alternative feedstocks and are being discussed in aviation as an alternative to conventional fossil-based fuels. Depending on feedstock, production pathway and comparison basis, SAF can contribute to lower lifecycle greenhouse gas emissions than conventional jet fuel in certain applications.

Properties
The different aviation fuels have specific compositions and physical characteristics:

- Jet A-1: A kerosene with a flash point above 38 °C and a freezing point of -47 °C.
- Jet B: A mixture of 65% gasoline and 35% kerosene, with a flash point of 20 °C and a maximum freezing point of -72 °C.
- AvGas 100 LL: A light leaded gasoline with 100 octane that meets special requirements with regard to the octane number.
- Blended (or 'finished') SAF: A mixture of kerosene and biofuels that has been tested in test flights and can be obtained from various renewable sources such as algae, jatropha and camelina oil.
- Neat (or 'unfinished') SAF: These fuels have similar chemical properties to fossil kerosene and can be blended with conventional jet fuel by up to 50%.

The quality standards are precisely defined for all aviation fuels to ensure safe use.

Application and importance in the market
Aviation fuels play a central role in the aviation industry. The use of Jet A-1 and Jet B is widespread and varies according to region and requirements. AvGas is mainly relevant in private aviation, while the military sector also uses Jet B.

Research and development into blended and neat SAF focuses on expanding available fuel options for aviation and assessing their potential role in future supply.  The importance of Sustainable Aviation Fuels are increasing, while at the same time prices are comparatively higher due to availability and production methods.

Quality assurance and different regulations depending on the country influence the use and market availability of these fuels.

Differentiation from similar terms
- Jet A-1 vs. Jet B: Jet A-1 is a pure kerosene, while Jet B is a kerosene-gasoline mixture that has a higher flammability.
- AvGas vs. Jet Fuel: AvGas is a high-octane gasoline for piston engines, as opposed to Jet Fuel, which is used for turbine engines.
- Blended (or 'finished') vs. neat (or 'unfinished') SAF: Blended SAF is a blend of kerosene and biofuels, while neat SAF is made entirely from sustainable feedstocks.

Summary
Aviation fuels are essential for the propulsion of airplanes and include different types such as Jet A-1, Jet B and AvGas. Intensive research is being conducted into bio-based alternatives such as blended SAF and Sustainable Aviation Fuels. These developments are relevant to ongoing efforts in aviation to explore fuel options that may support lower greenhouse gas emissions, depending on fuel pathway and application.Market availability and the legal framework play an important role in the application of these fuels.