A laboratory test rig has evaluated European jet fuels with regards to lubricity and shows that the more highly refined fuels are poorer in lubricity than the conventionally refined fuels. The addition of a surface active additive such as a corrosion inhibitor improves lubricity. Experience of additive addition to fuel for aircraft of two European airlines in 1968 confirms laboratory results. Highly polar compounds extracted from conventionally treated fuels significantly improve lubricity when added to highly refined fuels.
The blending of 10-20% of a conventionally treated fuel to a highly refined fuel improves lubricity to the level of the conventional fuel.