Cessna 172S Nav III User Manual

SECTION 7
AIRPLANE AND SYSTEMS DESCRIPTION
FUEL SYSTEM (Continued)
FUEL SELECTOR VALVE
CESSNA
MODEL 172S NAV
III
The FUEL SELECTOR valve should be in the BOTH position for
takeoff,
climb, landing, and maneuvers that involve prolonged slips
or skids of more than
30 seconds. Operation from either LEFT or
RIGHT tank is reserved for crUising flight.
NOTE
• When the FUEL SELECTOR valve handle is in the
BOTH position in cruising flight, unequal fuel flow
from each tank may occur if the wings are not
maintained exactly
level. Resulting wing heaviness
can
be alleviated gradually by turning the selector
valve handle to the tank
in the "heavy" wing. It is
not practical to measure the time required to
consume
all of the fuel in one tank, and, after
switching to the opposite tank, expect
an equal
duration from the remaining
fuel. The airspace in
both fuel tanks is interconnected by a vent line and,
therefore, some sloshing of fuel between tanks can
be expected when the tanks are nearly full and the
wings are not
level.
•
When the fuel tanks are 1/4 full or less, prolonged
uncoordinated flight such as
slips or skids can
uncover the fuel tank outlets. Therefore,
if operating
with one fuel tank dry or if operating
on LEFT or
RIGHT tank when 1/4 full or less, do not allow the
airplane to remain
in uncoordinated flight for
periods
in excess of 30 seconds.
FUEL DRAIN VALVES
The fuel system is equipped with drain valves to provide a means for
the examination of fuel
in the system for contamination and grade.
The system should be examined before each flight
and after each
refueling,
by using the sampler cup provided to drain fuel from each
wing tank sump, the fuel reservoir sump, the fuel selector drain and
the fuel strainer sump.
If any evidence of fuel contamination is
found,
it must be eliminated in accordance with the Preflight
Inspection checklist and the discussion
in Section 8 of this
publication.
If takeoff weight limitations for the next flight permit, the
fuel tanks should
be filled after each flight to prevent condensation.
7-42
U.S.
172SPHAUS-00

Cessna 172S Nav III Specifications

General

Brand	Cessna
Model	172S Nav III
Category	Aircrafts
Language	English