As a Petroleum Laboratory NCO, you play an important role in evaluating the quality surveillance procedures
at aviation unit refueling facilities. You must have a thorough base of knowledge in order to make the right
decisions. Without a thorough understanding of QCP, you cannot evaluate them.
PART A - IDENTIFY POTENTIAL SOURCE OF CONTAMINATION FOR
GROUND MOBILITY FUEL
Contamination with other Fuels (Commingling). Contamination of this type usually results from
an accidental mixing of different types of fuel during storage or transportation, or from refueling vehicles or
equipment with the wrong fuel. The effect of commingling varies with the amount and type of fuels. For
Contamination of diesel fuel with gasoline or JP-5 turbine fuel will lower the flash point of the diesel and
create a safety hazard.
Contamination of motor gasoline with diesel fuel will reduce the antiknock index (average of research
and motor octane number) and will cause increased engine deposits, as well as decrease storage
Contamination of unleaded gasoline with leaded gasoline will result in damaging the catalytic converter
in the using vehicles equipped with the emission control systems.
Water. Water in fuel may be either fresh or salt water and may be either dissolved or free water. Water in
fuel can arise by condensation, leakage, or seepage of ground water into underground storage tanks, or from
rain leaking into storage or vehicle tanks.
Dissolved water is water that has been solubilized in the fuel and is invisible. It usually does not pose a
threat to engines because the amount is generally less than 100 ppm. However, decreasing the fuel
temperature can cause dissolved water to come out of solution to form free water.
Free water may be in the form of an emulsion, fine droplets in suspension, or in large quantities, may
separate as bottoms of tank containers. Free water in ground fuel can cause stalling, injection fouling,
and other engine malfunctions, as well as being a cause of corrosion. In cold weather it may cause
blockage of fuel lines by freezing.
Sediment. Sediment may be in the form of dust, powder flakes, granular material, fibrous material,
agglomerates, sludge, or slime. Sediment includes both organic and inorganic matter. If the fuel container
or tank has a water bottom, some or all of the sediment may be present at the fuel and water interface.
Inorganic Sediment. Inorganic sediment includes metal and rust particles, siliceous material, and
mineral fibers such as fiberglass. Coarse sediment (greater than 10 microns) may clog fuel lines and
damage fuel injector pumps and other engine components.
Organic Sediment. Organic sediment consists primarily of deterioration of products of fuel and of
microbiological debris. The deterioration product takes the form of brown to black insolubles, gums, and
sludge that can clog filters and screens. Gums are the products of oxidation and polymerization of
unsaturated hydrocarbons frequently found in gasoline and distillate fuels. The use of Diesel Fuel
Stabilizer Additive will inhibit the formation of organic sediment and microbiological growth in diesel
PART B - EVALUATE THE QCP AT A BULK STORAGE FACILITY TO
DETERMINE IF THE CONTRACTOR ESTABLISHES AND MAINTAINS AN
ACCEPTABLE PROGRAM FOR THE CONTROL OF QUALITY OF
PETROLEUM PRODUCTS FURNISHED TO OR HANDLED FOR THE
Verify that the contractor has a satisfactory written description of their instruction system prior to
production or performance.