The Purity of Aviation Fuel

While functionally and chemically similar to the gas used in automobiles, aviation fuel is  different in several important ways. Like gasoline, aviation fuel used by aircraft is made up of numerous different hydrocarbons. The longer the hydrocarbons are and the higher the molecular weight of these compounds, the more chemical parameters such as melting point or smoke point differ. Gasoline, for instance, typically has seven to eleven carbon atoms with hydrogen atoms attached, while aviation fuel ranges from twelve to fifteen carbon atoms with attached hydrogen atoms. These chemical parameters can have an enormous influence on the quality of the fuel, with one of the most important for quality control being the viscosity.

Fuel purity is of course vitally important for the aviation industry. If the fuel is contaminated by water, ice can form in the fuel tanks and fuel lines while flying at high altitudes, which can disrupt the flow of fuel to the turbines and cause them to shut down. To prevent this from happening, the American Society for Testing and Materials (ASTM) develops and publishes standards for fuel purity based on viscosity. These standards are recognized and used around the world and cataloged in ASTM D1655 and ASTM D7566.

When fuel’s viscosity is too high, the injection nozzles in the turbines will struggle to spray it. This effectively shortens the working lifespan of the nozzles, which leads to higher maintenance costs and makes re-ignition more difficult if the engine fails mid-flight. The viscosity also affects the pressure drop in the fuel lines, with the greater the viscosity the higher the pressure drops. The fuel pump then has to work harder to ensure a constant flow rate so that the turbines can continue to function. On the other hand, when the viscosity is too low, the lack of lubrication in the system can lead to a total engine failure.

Fortunately, instruments called viscometers can easily check the viscosity and density of aviation fuel to ensure the fuel is within proper parameters before it is pumped into the aircraft, and numerous procedures are taken throughout storage and fueling to prevent water contamination.

At Sourcing Streamlined, owned and operated by ASAP Semiconductor, we can help you find all the fueling equipment for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at or call us at 1-714-705-4780.


November 2, 2022

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