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CESSNA
MODEL 172N
SECTION 8
HANDLING, SERVICE
&
MAINTENANCE
Therefore, to alleviate the possibility of fuel icing occurring under
these unusual conditions, it i s permissible to add isopropyl alcohol or
ethylene glycol monomethyl ether (EGME) compo-imd to the fuel
supply.
The introduction of alcohol or EGME compound into the fuel provides
two distinct effects: (1) it absorbs the dissolved water from the gasoline
and (2) alcohol has a freezing temperature depressant effect.
Alcohol, if used, i s to be blended with the fuel in a concentration ofJYo
by volume. Concentrations greater than
1%
are not recommended"
since they can be detrimental to fuel tank materials.
The manner in which the alcohol i s added to the fuel is significant
because alcohol is most effective when it is completely dissolved in the
fuel. To ensure proper mixing, the following is recommended:
1. For best results, the alcohol should be added duringthefueling
operation by pouring the alcohol directly on the fuel stream
issuing from the fueling nozzle.
2.
An alternate method that may be used is to premix the
complete alcohol dosage with some fuel in a separate clean
container (approximately 2-3 gallon capacity) and then
transferring this mixture to the tank prior to the fuel operation.
Any high quality isopropyl alcohol may be used, such as Anti-Icing
Fluid (MIL-F-5566) or Isopropyl Alcohol (Federal Specification TT-I-
735a). Figure 8-1 provides alcohol-fuel mixing ratio information.
Ethylene glycol monomethyl ether (EGME) compound, in compliance
with MIL-1-27686 or Phillips PFA-55MB, if used, must be carefully
mixed with the fuel in concentrations not to exceed .15% by volume.
Figure 8-1 provides EGME-fuel mixing ratio information.
CAUTION
Mixing of the EGME compound with the fuel i s extremely
important because a concentration in excess of that recom-
mended (.15% by volume maximum) will result in detri-
mental effects to the fuel tanks, such a s deterioration of
protective primer and sealants and damage to O-rings and
seals in the fuel system and engine components. Use only
blending equipment that is recommended by the manufac-
turer to obtain proper proportioning.
1
July
1979
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