Because of the serious consequences of a turbine engine failure and the nature of the fuel systems in turbine engines, provide designs which include means to prevent contamination of aviation turbine fuels by dirt, water, or other types of fuels. Solid contaminants are generally those which are insoluble in fuel. Most common are iron rust, scale, sand, and dirt. Iron rust contaminates aviation turbine fuel, and carbon steel contact degrades thermal stability. Special filtration is required for receiving aviation turbine fuel into bulk storage and ready issue (operating storage) to remove contaminants before the fuel is delivered to aircraft. To preserve fuel quality, limit materials in contact with the fuel to stainless steel, non-ferrous, or coated carbon steel for aircraft fueling systems. Do not use zinc, copper, and zinc- or copper-bearing alloys in contact with aviation turbine fuels, including pipe, valves, equipment, and accessories. The maximum allowable aircraft servicing use limits of solids is 2.0 mg/L and the maximum allowable aircraft servicing use limits of free water is 5 ppm. Provide a design that precludes disposing of aviation turbine fuels into storm or sanitary sewers.
