Icing inhibitors, also known as anti-icing additives or fuel system icing inhibitors (FSII), are chemicals added to aviation fuels to prevent the formation of ice crystals in the fuel system of aircraft. These ice crystals can cause engine failure or blockages in fuel lines, leading to dangerous situations during flight.
Icing inhibitors work by lowering the freezing point of water in the fuel system, preventing ice crystal formation. This is important because aviation fuels, such as Jet A and Jet A-1, contain small amounts of water due to their hygroscopic nature. When the fuel temperature drops below freezing, this water can form ice crystals, which can block fuel filters and cause engine failure.
There are two main types of icing inhibitors: ethylene glycol-based and diethylene glycol-based. Ethylene glycol-based inhibitors are more effective at lower temperatures and are commonly used in colder climates. On the other hand, Diethylene glycol-based inhibitors are less effective at low temperatures but are more environmentally friendly and have lower toxicity.
Icing inhibitors are an essential component of aviation fuel that helps ensure an aircraft’s safe and reliable operation in cold weather conditions.