Cessna 172N - Electrical and Pitot-Static Systems

CESSNA
MODEL 172N
SECTION
7
AIRPLANE
& SYSTEMS
DESCRIPTIONS
connected by a
vent
line
and, therefore, some
sloshing
of fuel between tanks can be
expected when
the tanks
are
nearly
fuIl
and
the wings
are
not
level.
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
the
first flight
of every
day
and after
each
refueling, by using the
sampler
cup
provided
to drain
fuel
from the
wing tank sumps,
and
by utilizing
the fuel
strainer
drain
under an access
panel
on the right
side
of the engine cowling.
The
fueI
tanks
shorltd
be
filled
after each
flight
to
prevent
condensation.
BRAKE
SYSTEM
The airplane has a
single-disc,
hydraulically-actuated
brake
on each
main landing
gear
wheel.
Each brake is connected,
by
a
hydraulic line,
to a
master cylinder attached
to
each
of the
pilotts
rudder
pedals.
The
brakes are operated by applying
pressure
to the top of either
the
left
(pi-
lotts) or right
(copilot?s)
set
of rudder
pedals,
which are
interconnected.
When
the
airplane
is
parked,
both
main
wheel brakes may
be
set
by
utiliz-
ing
the
parking
brake
which
is operated
by a handle under
the left
side
of
the instrument
panel.
To apply
the
parking
brake,
set
the bral<es with
the
mdder
pedals, prll
the handle
aft, and rotate it 90'
down.
For
maximum
brake
life, keep
the brake
system
properly
main-
tained,
and minirnize
brake usage during
taxi operations
and landings.
Some of the
symptoms of
impending
brake
failure
are:
gradual
decrease
in braking action
after
brake
application, noisy or dragging
brakes,
soft or
spong'y
pedals,
and
excessive travel and weak braking
action. If any
of
these
symptoms appear,
the brake system is
in need
of
immediate
attention.
If,
during taxi or
landing roII,
braking action
decreases,
let
up
on the
pedals
and then re-apply
the brakes
with heavy
pressure.
If
the brakes
become spongy or
pedal
travel increases,
pumping
the
pedals
should
build
braking
pressure.
If one brake be-
comes weak
or fails, use the other brake
sparingly
while using
oppo-
site rudder,
as
required,
to
offset
the
good
brake.
ELECTRICAT
SYSTEM
Electrical enerry
(see
figure
7-7) is
supplied by
a 14-volt,
direct-
current system
powered
by an engine-driven, 60-amp
alternator. The
12-volt, 25-amp
hour
battery is located
on
the left
side
of the firewall.
Power
is
supplied
to
all
electrical circuits through
a
split bus bar,
one
side containing electronic system
circuits and the other
side
having
gen-
eral electrical
svstem circuits. Both sides of the
bus
are on
at
all times
7
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