Cessna 172P Pilot's Operating Handbook And Flight Manual page 145

CESSNA
MODEL
172P
SECTION
7
AIRPLANE & SYSTEMS
DESCR,IPTIONS
FUEL
OUANTITY DATA
(U,S.
GALLONS}
FUEL TANKS
FUEL
LEVEL
(OUANTITY
EACH TANK}
TOTAL
FUEL
TOTAL
UNUSABLE
TOTAL
USABLE
ALL
FLIGHT
CONDITIONS
STANDARD
FU
LL
(21.5)
43 3
40
LONG
RANGE
FULL
l27t
54
4
50
LONG
RANGE
(INTEGRAL
TANKS)
FU
LL
(34)
68
6
62
LONG RANGE
(INTEGRAL
TANKS}
REDUCED
l24l
48
6
42
Figure 7-õ. FueI Quantity Data
fuel from the fuel strainer
and
injects
it
into the cylinder intake ports.
Fuel system venting is
essential to system operation. Blockage
of
the
system
will
result in
decreasing
fuel flow
and
eventual engine
stoppage.
Venting
is
accomplished by
an
interconnecting line from the right
fuel
tank
to
the left tank.
The
left fuel tank is
vented overboard
through
a
vent
line,
equipped
with a
check valve, which protrudes
from the
bottom
surface
of
the
left wing nearthe wing strut.
The
right fuel tank
fitler
cap
is
also vented.
When
long
ra,nge
integral tanks
are installed, the airplane may
be
serviced
to
a
reduced
capacity to permit heavier
oa,bin
loadings. This is
accomplished
by
filling
each
tank to the bottom
edge
of the fuel
filler
collar, thus
giving
a
reduced
fuel load
of
24
gallons in
each
tank
(21
gallons
usa,ble
in all flight
conditions).
Fuel quantity
is measured by two
float-type
fuel
quantity transmitters
(one
in
each
tank)
and
indicated
by
two electrically-operated fuel quantity
indioators on the left side of the instrument penel. An empty tank is
indicated by
a
red
line
and
the
letter
E. When an
indicator
shows
an
empty
tank, approximately
1.5
gallons remain in
a
standard tank,
and
2
gallons
remain
in
a
long
range tank
(8
gallons
when
long
range
integral tanks
are
installed) as
unusable
fuel. The indicators cannot be relied upon for
accurate readings during skids, slips, or unusual attitudes.
The
fuel
selector
valve
should
be
in
the BOTH position
for
takeoff,
80
May
1980
7-21