The Most Common Aviation Fuel: Jet A-1 and Its Applications

When discussing aviation fuels, one term often comes to the forefront: Jet A-1. This refined petroleum product is the standard fuel for the vast majority of commercial and military aircraft. But what exactly is Jet A-1, and how does it differ from other aviation fuels such as Avgas?

Jet A-1: The Global Standard for Aviation Turbine Fuel

Jet A-1 is a clear, light hydrocarbon fuel that is widely used in turbine engines of civil and military aircraft. It is a specialized form of kerosene, which makes it well-suited for high-efficiency turbojet and turboprop engines. Jet A-1 is distinguished by its flash point (more than 38°C) and freezing point (-47°C).

Since the majority of aviation operations are commercial flights, and most commercial aircraft require turbojet engines, Jet A-1 is the go-to fuel for these operations. This widespread usage makes Jet A-1 the most common aviation fuel worldwide.

Aviation Fuels: Diverse and Specialized

While Jet A-1 dominates commercial aviation, there are other types of aviation fuels that cater to specific aircraft and their requirements. These include:

Aviation Turbine Fuel

Primarily used in aircraft equipped with gas turbine engines (jet engines, turboprops), aviation turbine fuel is a refined kerosene product. It is designed to meet the high demands of modern jet engines and is used globally in both commercial and military sectors.

Aviation Gasoline (Avgas)

Also known as Avgas, aviation gasoline is a high-octane, leaded fuel designed for use in piston aircraft engines. It is significantly more expensive than Jet A-1 and is essential for older or high-performance engines that require a higher octane rating.

Types of Avgas

There are several types of Avgas available, each tailored to specific engine requirements. Some key examples include:

85/87 Octane Fuels: These are less common, having been phased out in the late 1990s due to their high TEL (Tetraethyl Lead) content. They are now almost impossible to find and were colored red.

91/115 Octane Fuels: Also referred to as leaded Avgas, this type is found in many Commonwealth countries and regions, including the CIS. It is colored green and is used in certain Russian-made radial engines.

100LL (Leaded Low Lead): This is the most common Avgas type used worldwide. It contains a reduced amount of TEL compared to older automotive fuels and is easily accessible. It is colored blue and is used in most general aviation piston engines.

110/130 Octane Fuels: These high-octane, fully leaded fuels are now largely replaced by 100LL and are rarely found outside of specific regions, such as Utah in the United States.

Each type of Avgas is designed for specific engines and performance requirements, but the vast majority of general aviation pilots use 100LL due to its widespread availability and lower cost.