UNDERSTANDING THE ELEMENTS

Aircraft Engines

Elements are quantified in the oil at part per million levels (PPM). This list shows the most common sources of the elements from an aircraft engine.

Aluminum: Pistons, piston pin plugs, bearings and the case (fretting). Chromium : Rings, (replacement) cylinders, a trace element in steel. Iron: Cylinders, rotating shafts, the valve train, and any steel part sharing the oil. Copper: Brass or bronze parts, bushings, bearings and oil coolers. Lead: Primarily leaded gas blow-by, (traces from) bearings. Tin : Bearings, bronze parts (with copper), anti-wear coatings. Molybdenum: Traces of anti-wear coatings, some cylinder types. Nickel : Valve guides, trace element in steel. Manganese: Grease additive. Silver: Trace element in some types of bearings. Titanium/Potassium: Trace elements. Boron/Sodium: Contamination, common to antifreeze. Silicon : Abrasive dirt (via intake air), silicone sealers and gaskets. Calcium/Magnesium: Oil additives, rare in aircraft engine oils. Phosphorus : Common anti-wear additive in aircraft oils. Zinc: Component of brass (with copper), oil additive common to auto engine oils. Barium : Additive used in some synthetic oils, not common to aircraft oils.

Physical properties:

• Viscosity/Flashpoint: Used to determine the oil grade and % fuel in the oil.
• Fuel %: Indicates the amount of volatile gas found in the oil.
• Water %: Indicates the amount of moisture found in the oil.
• Insolubles %: Indicates total solids particulate from oil oxidation and blow-by.