SECTION 8
CESSNA
HANDLING, SERVICE AND MAINTENANCE
MODEL 172S NAV III
FUEL
(Continued)
FUEL CONTAMINATION
Fuel contamination is usually the result of foreign material present
in the fuel system, and may consist of water, rust, sand, dirt,
microbes or bacterial growth. In addition, additives that are not
compatible with fuel or fuel system components can cause the fuel
to become contaminated.
Before each flight and after each refueling, use a clear sampler cup
and drain at least a cupful of fuel from each fuel tank drain location
and from the fuel strainer quick drain valve to determine if
contaminants are present, and to ensure the airplane has been
fueled with the proper grade of fuel.
If contamination is detected, drain all fuel drain points including the
fuel reservoir and fuel selector quick drain valves and then gently
rock the wings and lower the tail to the ground to move any
additional contaminants to the sampling points. Take repeated
samples from all fuel drain points until all contamination has been
removed. If, after repeated sampling, evidence of contamination still
exists, the airplane should not be flown. Tanks should be drained
and system purged by qualified maintenance personnel. All
evidence of contamination must be removed before further flight. If
the airplane has been serviced with the improper fuel grade, defuel
completely and refuel with the correct grade. Do not fly the airplane
with contaminated or unapproved fuel.
In addition, Owners/Operators who are not acquainted with a
particular fixed base operator should be assured that the fuel supply
has been checked for contamination and is properly filtered before
allowing the airplane to be serviced. Fuel tanks should be kept full
between flights, provided weight and balance considerations will
permit, to reduce the possibility of water condensing on the walls of
partially filled tanks.
To further reduce the possibility of contaminated fuel, routine
maintenance of the fuel system should be performed in accordance
with the airplane Maintenance Manual. Only the proper fuel, as
recommended in this handbook, should be used, and fuel additives
should not be used unless approved by Cessna and the Federal
Aviation Administration.
8-22 U.S.
172SPHAUS-00