3. Clean out pipelines.
4. Remove contaminated tanks from service and
clean them thoroughly.
5. Recirculate fuel and return it to the system up-
stream of as many falter/separators as possible.
6. Investigate the source of contamination and
eliminate it. Notify cognizant Military Inspection Serv-
ice and Navy Fuel Supply Office if fuel is contaminated
The inadvertent mixing of two or more different
fuels is known as commingling. Most hydrocarbon
products (greases, oils, alcohols, and so on.) are readily
capable of mixing with other hydrocarbon products and
cannot be separated by mechanical means such as set-
tling, filtering, or centrifuging. A fuel that has been
contaminated by commingling with another petroleum
product is extremely dangerous whether in storage or in
use, because there may be no apparent visual or odor
This type of contamination is usually caused by
carelessness or a misunderstanding of the operations of
a fuel system. Most fuels systems are segregated from
each other and from other types of fuel systems; but in
some cases the piping of one fuel system may be inter-
connected with another system through valves, blanks,
or flanges. The inadvertent opening of a wrong valve
can result in commingling the two different products.
In other instances, fuel maybe pumped into a tank
that has contained another product without the tank
being properly cleaned. The small amount of the other
product may be enough to contaminate the fuel.
JP-5 contaminated with other jet fuels or gasoline
must not be stored aboard aircraft carriers unless a
laboratory test indicates that the flash point is within the
allowable limits of the specifications.
Because of the problem in detecting commingled
fuels, you must be careful where two different fuels
are handled in close association.
INSPECTION OF FUEL
The fuel systems and mobile refuelers now in use
by the Navy are designed to deliver an acceptable
uncontaminated fuel safely into the tanks of an aircraft
when they are properly operated. To ensure that this
fueling equipment is working properly and is being
operated properly, samples of the fuel must be taken
at several points and after each step in the operation.
A sample is a small part of a quantity of a fuel
representative of the quality or condition of the total
quantity of that fuel, suitable for visual or chemical
All ABFs must know the procedures for drawing of
samples and examining them for visual contamination.
A sample must be taken in such a manner and from such
a location that the sample will be a true representative
of the fuel sampled.
Many types of samples and sampling methods are
used in the inspection of fuels. The four most common
ones are discussed here.
A single tank composite sample is a blend of
samples taken from the upper, middle, and lower lev-
els of a tanks contents. A multiple tank composite
sample is a blend of individual all-levels samples from
each of the tanks that contain the same type of product
being sampled. These samples are in proportion to the
volume of the product in each tank.
This sample is one obtained by submerging a
closed sampler (thief) to a point as near as possible to
the drawoff level, then opening the sampler and rais-
ing it at such a rate that it is nearly but not quite full
as it emerges from the liquid.
A line sample is one taken from a pipeline or hose
at or near the discharge point before commencing
delivery and during the first few minutes of pumping.
This sample is taken to give an initial visual identifi-
cation of the fuel.
This type of sample is used for packaged stocks of
fuel. One container from a large stock of packaged fuel
when all are of the same age and grade may be selected
as a representative of the entire stock. When the con-
tainers of fuel are small and suitable for shipment, a
container of fuel is taken as the sample without its
being opened. For drums of fuel, the sample is drawn
from one drum.