Jet A and Jet A1
This kerosene grade of fuel is suitable for most turbine engine aircraft and is the type of fuel most commonly used by commercial airlines worldwide. In summer in the United States and certain Canadian airports, Jet A is the standard aviation fuel used. The main difference between Jet A and Jet A-1 is the freeze point (low temperature limiting the quality): Jet A has a maximum freeze point of -40°C, while Jet A-1 has a maximum freeze point of -47°C. Jet A-1, with its lower freeze point, is often used for long hauls and high-altitude flights when fuel in the wings can reach very low temperatures close to the freezing point. Military aircraft in Canada and the U.S. use a version of Jet A-1 called F-34, a kerosene grade of fuel with a freeze point of -47°C and two additives: fuel system icing inhibitor (FSII) and corrosion inhibitor.
Fuel System Icing Inhibitor (FSII)
When flying in cold climates or at very high altitudes, ice can form in fuel tanks. Ice crystals can form in the water that gets separated from the fuel as temperatures drop and can block filters. FSII blends with the free water in the fuel to lower its freeze point.
This additive must be added at a controlled rate of 0.10 to 0.15% in a fuel flow to make sure it gets completely dissolved. Note: DiEGME (DiEthylene Glycol Monomethyl Ether) additive is the only anti-icing additive approved by the Canadian and U.S. military.
Aviation fuel distribution systems such as tanks, pipes and certain engine components are mainly made of uncovered steel. Corrosion inhibitors are used to prevent free water and oxygen in the fuel to corrode those components.
Static Dissipator Additive (SDA)
Refining processes can naturally remove the polar molecules present, resulting in fuels with low conductivity. These fuels can build up static electrical charges, which can lead to a discharge when the fuel is loaded up or moves through the filters. To eliminate this risk, SDA can be added to the kerosene. Stadis 450 is the only additive being manufactured for use in jet fuel. CAN/CGSB-3.24 requires the use of the additive to reduce the risk from electrostatic charges.