System; Systems - Cessna Skyhawk Owner's Manual

TRANSMITTER
SELECTOR SWITCH.
ELECTRICAL SYSTEM.
The
transmitter
selector
switch, labeled "TRANS,
"
has
two
positions.
Electrical
energy
is supplied by a 14-volt,
direct-current
system
When
two transmitters
are
installed, it is necessary
to
switch
the micro-
powered
by an engine-driven
alternator (see
figure
2-3). A 12- volt bat-
phone
to the
radio unit
the
pilot desires
to
use for
transmission.
This is
tery
is located on
the left-hand
forward portion of
the
firewall. Power is
accomplished
by placing
the transmitter
selector
switch
in
the
position
supplied
to
all electrical circuits
through
a split bus bar, one side
con-
corresponding
to the
radio
unit which
is
to
be used. The
up position
taining
electronic systems and
the
other side having general electrical
selects
the
upper
transmitter
and
the
down position selects
the
lower
systems. Both sides of
the
bus are on at all
times
except when either an
transmitter.
external power
source
is connected or
the
ignition/starter
switch
is
turned
on;
then
a power
contactor is automatically
activated
to
open
the
circuit
to
The installation of
Cessna
radio equipment
provides certain
audio
the
electronic bus. Isolating
the
electronic
circuits in
this
manner
pre-
back-up
capabilities and
transmitter selector
switch
functions
that the
vents harmful
transient
voltages from damaging
the transistors
in
the
pilot
should be familiar
with. When
the transmitter
selector
switch
is
electronic equipment.
placed in position 1 or 2,
the
audio amplifier of
the
corresponding
trans-
ceiver
is utilized
to
provide
the
speaker
audio for
all
radios. If
the
audio
amplifier
in
the
selected
transceiver
fails, as
evidenced
by loss
of
speaker
AMMETER.
audio for all radios, place
the transmitter selector switch
in
the
other
transceiver
position.
Since an audio amplifier
is not utilized
for head-
The
ammeter
indicates
the
flow of current, in amperes, from
the
phones,
a malfunctioning amplifier will not affect
headphone operation.
alternator
to the
battery or from
the
battery
to the
aircraft electrical
system. When
the
engine is operating
and
the
master switch is "ON,
"
the
ammeter
indicates
the
charging rate applied
to the
battery. In
the
SPE A KERPHONESW ITCHE S.
event the alternator
is not functioning or
the
electrical load exceeds
the
output of
the
alternator,
the
ammeter
indicates
the
discharge rate of
the
The
speaker-phone
switches determine whether
the
output of
the
battery.
receiver in
use
is fed
to the
headphones or
through the
audio
amplifier
to the
speaker. Place
the
switch for
the
desired receiving
system either
in
the
up position for speaker operation or in
the
down position
for head-
CIRCUIT BREAK
ERS AND FUSES.
phones.
The majority of
electrical
circuits in
the
airplane are protected by
"push-to-reset"
circuit
breakers
mounted
on
the
instrument panel.
Ex-
A UTO PI
LO T- OMN
I
SW I TCH.
ceptions
to this
are
the
optional clock, flight hour recorder,
and
battery
contactor closing (external power) circuits which have fuses mounted
When a Nav-O-Matic
autopilot is installed with
two
compatible omni adjacent
to the
battery.
Also,
the
cigar lighter is protected
by a man-
receivers,
an
autopilot-omni
switch is
utilized.
This switch selects
the
ually reset
type
circuit breaker mounted directly on
the
back of
the
lighter
omni receiver
to
be
used
for
the
omni
course
sensing function of
the
auto-
behind
the
instrument panel. The alternator
field
and
wiring
is protected
pilot. The
up
position selects
the
upper
omni receiver in
the
radio
panel
by an automatically resetting circuit breaker.
stack and
the
down position selects
the
lower omni receiver.
LANDING LIGHTS
(OPT).
A
three-position, push-pull
switch controls
the
optional landing
lights. To
turn
one lamp on
for taxiing,
pull
the
switch out
to the
first
stop.
To
turn
both lamps on for landing, pull
the
switch
out
to the
sec-
ond stop. To
turn
both lamps off,
push
the
switch
full
in.
6-4 2-3