Cessna 152 - Page 134

SECTION7
AIRPLANE
&
SYSTEMS
DESCRIPTIONS
CESSNA
MODEL 152
The
stall
warning
system
should
be
checked
during
the
preflight
inspection
by
placing
a
clean
handkerchief
over
the
vent
opening
and
applying
suction.
A
sound
from
the
warning
horn
will
confirm
that
the
system
is
operative.
AVIONICS
SUPPORT
EQUIPMENT
If
the
airplane
is
equipped
with
avionics,
various
avionics
support
equipment
may
also
be
installed.
Equipment
available
includes
two
types
of
audio
control
panels,
microphone/headset
installations
and
control
surface
static
dischargers.
The
following
paragraphs
discuss
these
items.
Description
and
operation
of
radio
equipment
is
covered
in
Section
9
of
this
handbook.
AUDIO
CONTROL
PANEL
If
an
audio
control
panel
(see
figure
7-10)
is
installed
in
the
airplane,
it
will
be
one
of
two
types,
either
with
or
without
marker
beacon
controls.
The
features
of
both
audio
control
panels
are
similar
and
are
discussed
in
the
following
paragraphs.
TRANSMITTER
SELECTOR SWITCH
When
more
than
one
NA
V / COM
radio
is
installed
in
the
airplane,
it
is
necessary
to
select
the
radio
unit
the
pilot
desires
to
use
for
transmitting.
To
accomplish
this,
a
transmitter
selector
switch
is
provided
on
the
audio
control
panel.
The
switch
is
either
a
two-position
toggle-type
or
a
three-
position
rotary-type
depending
on
which
audio
control
panel
is
installed.
Both
switches
are
labeled
with
numbers
which
correspond
to
the
top
(number
1)
or
the
bottom
{number
2)
NAV/COM
radio.
Position
3
is
not
used
in
this
airplane.
The
audio
amplifier
in
the
NA
V / COM
radio
is
required
for
speaker
and
transmitter
operation.
The
amplifier
is
automatically
selected,
along
with
the
transmitter,
by
the
trans~itter
selector
switch.
As
an
example,
if
the
number
1
transmitter
is
selected,
the
audio
amplifier
in
the
associated
NA
V / COM
receiver
is
also
selected,
and
functions
as
the
amplifier
for
ALL
speaker
audio.
In
the
event
the
audio
amplifier
in
use
fails,
as
evidenced
by
loss
of
all
speaker
audio
and
transmitting
capability
of
the
selected
transmitter,
select
another
transmitter.
This
should
re-establish
speaker
audio
and
transmitter
operation.
Since
headset
audio
is
not
affected
by
audio
amplifier
operation,
the
pilot
should
be
aware
that,
while
utilizing
a
headset,
the
only
indication
of
audio
amplifier
failure
is
loss
of
the
selected
7-32
1
July
1978