Kerosene Type Jet Fuel also known as Jet A consist essentially of the heavier hydrocarbon fractions and are more dense than the wide cut gasoline type fuel ( Jet B ). There is NO specific gravity or vapor pressure difference between Kerosene and Jet A. There is however, most often the addition of PRIST ( PFA 55MB covered by MIL-I-27686D ) main ingredient ethylene glycol monomethyl ether to Jet A. Prist is added to prevent icing and bacterial contamination ONLY. The recommended concentration of Prist in fuel is 0.06 - 0.15 percent by volume.

The above information as noted in Aircraft Powerplants 6th edition ( Kroes,Wild, Bent, McKinley )

Dean
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