Table 2-3. Visual Contaminant Characteristics

TM 1-1500-20423-3 Table 2-3. Visual Contaminant Characteristics Type contaminants Appearance Characteristics Water Dissolved water Not visible. Fresh water only. Appears as cloud when fuel is cooled. Free water Light cloud; heavy cloud; Free water may be saline water droplets adhering to sides or fresh water. Cloud usually in- of bottle or gross amounts dicates water-in-fuel emulsion. settled in bottom. Particulate Matter Rust Red or black powder; rouge, Red rust - non-magnetic or grains. May appear as Black rust - magnetic dye-like material in fuel. Most particulate matter is generally rust. Grit, sand, or rust Crystalline, granular or Usually present in main fuel glass-like. filter or fuel inlet strainer and servo supply filter. Occasionally constitutes major constituent. Aluminum or magnesium White or gray powder or Sometimes very sticky or gela- compounds paste. tinous when wet with water. Usually present and occasionally represents major constituent. Microbiological Growth Red-brown, gray, or black. Usually found with other Stringy or fibrous. contaminants in the fuel. Very light weight; floats or swims in fuel longer than water droplets or solid particles. Develops only when free water is present. Emulsions Water-in-fuel emulsions Light cloud; heavy cloud. Finely divided drops of water in fuel. Same as free water cloud. Will settle to bottom in minutes, hours, or weeks depending upon nature of emulsion. 2-4