Aviation | Determination of Fuel System Icing Inhibitors in Aviation Fuels
Fuel system icing inhibitors in aviation fuels prevent the formation of ice in fuels in order to ensure a safe flight in military and civil flights. According to ASTM D 5006 the concentration of fuel system icing inhibitors can be determined with high accuracy.
Jet fuel may contain a small amount of dissolved water. The jet fuels capacity to hold water diminishes with reduction in temperature. This process takes place every time an aircraft gains altitude, as the outside temperature at cruising altitude is around -50 °C. Under these circumstances water may separate and cause serious problems when freezing in fuel lines or filters, therefore blocking the flow of fuel and shutting down the engine. To prevent the formation of ice in fuel lines, a fuel system icing inhibitor (FSII) is added to jet fuel
As a FSII, nearly pure (99.9 %) diethylene glycol monomethyl ether (DiEGME) is used. It dissolves readily in water and is added to jet fuel in a final concentration of 0.10 % to 0.15 %. This lowers the freezing point of water to -43 °C. FSII are mandatory in all military aircraft fuels and used in commercial civil aviation fuels depending on routes, flight lengths, and season.
Large aircrafts do not require FSII as they are usually equipped with electric fuel line heaters to prevent icing. However, in case the fuel heaters are inoperable, an aircraft may still be declared fit to fly with FSII added to the fuel.
As DiEGME is soluble in water it can be extracted from the fuel by contact with water during shipping and in storage. Therefore, it is very important to check the additive content in the fuel to ensure proper additive concentration. This procedure is continuously performed at customer sites with FSII demanding applications, e.g. at air forces.
Get the document
To receive this document please enter your email below.
