Textron Cessna 172S Skyhawk SP, Information Manual

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CESSNA
MODEL 172S
SECTION 3
EMERGENCY PROCEDURES
EXCESSIVE FUEL VAPOR INDICATIONS
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Excessive fuel vapor is.most likely to be generated during groun
operations when operating at higher altitudes, in unusually war
temperatures or with ,more volatile fuel blends. Operation at or nea
Idle RPM (low fuel flow) for extended periods will increase th
chances of fuel vapor generation. (See "Leaning For Groun
Operations", Section 4.)
Indicated fuel flow that is not stable (sudden changes greate
than 1 gal/hr) is a sign that fuel vapor may be present in the system
Fuel flow indications that become less stable (increasing changes
may lead to power surges and power loss if not corrected.
If in-flight vapor is suspected, smoother engine operation ma
result from making the following changes (singly or together): ~ se
the auxiliary fuel pump to the ON position, lean the mixture fo
smooth engine operation and select another fuel tank. Increasin
the airspeed to provide more air flow through the cowling will aidi
cooling the engine and fuel system components.
LOW OIL PRESSURE
If the low oil pressure annunciator (OIL PRESS) illuminates and
oil temperature remains normal, the oil pressure sending unit o~
relief valve may be malfunctioning. Land at the nearest airport t
inspect the source of trouble. .
..If a total loss of oil pressure is accompanied by a rise "in oil
temperature, there is good reason' to .suspect an engine failure is
imminent. Reduce engine power immediately' and select a suitable
forced landing field .. Use only the minimum power required to reach
the desired touchdown spot.
Revision 4
3-211