Cessna 172P - Cabin Heating, Ventilating and Defrosting; Pitot-Static; System

SECTION
7
AIRPLANE
& SYSTEMS
DESCN,IPTIONS
CESSNA
MODEL 172P
short
circuit (smoke
or
odor),
turn
off
the light
switch
of the
affected
tights,
reset
the
breaker,
and
turn the
switch
on agãin.
If the
breaker
opens
a[ain.
do not
reset
it.
CABIN HEATING,
VENTILATING
AND
DEFROSTING
SYSTEM
The
temperature
and volume
of
airflow
into
the
cabin can
be
regulated
by
manipulation
of the
push.pull
CABIN
HT
and
OABIN
AIR
õontrol
knobs
(see
figure
7-8).
For
cabin ventilation, pull
the
CABIN etn Anon out.
To raise the
air
temperature,
pull
the
CABIN
HT knob
out approximately
1/4 to 1/p inch
for
a small
amount
of cabin
heat.
Additional heat
is available
by
pulling
the
knob
out fartheri
maximum
heat is
available with the
CABIN HT knob
pulled
out and
the
CABIN AIR,
knob
pushed
full in.
When
no
heat
is
desired
in the
cabin,
the
CABIN HT knob
is
pushed
full in.
Front cabin
heat
and ventilating
air is
supptied by ouilet
holes
spaced
Eùcross a
cabin
manifold
just
forward
of the
pilot's
and
copilot's
feet.
Rear
cabin heat
and
air is
supplied by
two
ducts from
the manifold,
one
extending
down
each side
of the
cabin
to an outlet
at
the front
doorpost at
floor level.
Windshield
defrost
air is also
supptied
by two
ducts leading
froln
the
cabin
manifold
to defroster
outlets
near the lower
edge of the
windshield.
Two
knobs
control
sliding valves
in either defroster
ouilet to
perrnit
regulation
of
defroster
airflow.
Separate
adjustable
ventilators
supply
additional
airi
one
near each
upper
corner
of
the
windshield
supplies
air
for
the
pilot
and
copilot,
and
two
ventilaüors
are
available
for
the
rear
cabin
area to
supply
air tb
the
rear
seat
passengers.
The airplano
may
also
be
equipped
withãn
air condition-
ing
system.
For operating
instructions
and
deteils
concerning
this
system,
refer
to
Section
9,
Supplemeuts.
PITOT-STATIC
SYSTEM
AND INSTRUMENTS
The
pitot-static
system
supplies
ram
air
pressure
to the
airspeed
indicator
and static
pressure
to the
airspeed
indicator, vertical
speed
indicator
and altimeter.
The
system is
composed
of
either an
unheated
or
heated
pitot
tube
mounted
on the lower
surface
of the leftwing,
an external
static
port
on the lower
left
side
of the forward fuselage,
and the associated
plumbing
necessary
to connect
the instruments
to the
sources.
7-30
30
May
1980