Fuel System Icing Inhibitor (FSII)
Aviation fuel may contain a small amount of dissolved water. At the low temperatures prevailing at high altitudes, the water may phaseseparate and freeze, leading to the formation of ice crystals that may block filters or fuel pathways. This problem is especially critical for business jets, general aviation and some military aircrafts. These aircrafts can lack the substantial heat exchangers required to deal´with ice that may develop in the fuel system and often rely on manual draining only to remove water from the fuel tanks.
MIL-I-85470 B and DERD 2451
KEROFLUID® MIL-AL-41 fuel system icing inhibitor is an antiicing additive for aviation turbine fuels. When present in jet fuel, it depresses the freezing point of water to temperatures that are in the vicinity of the freezing point of jet fuel itself. As a result, issues associated with ice formation are mitigated.