Beechcraft C-12C Operator And Technical Reference Manual page 400

TM 1-1510-218-10
(3) Program Mode. The preset channels and
frequencies are set using the program mode.
Pressing and holding the CHAN switch for 2 seconds
will place the unit into the program mode. A – P- and
a channel number will be shown in the active display,
and a frequency or dashes will be shown in the
standby display. Immediately after entering the
program mode the channel number will begin to flash,
indicating that rotating the tuning knobs will change the
channel number. Momentarily pressing the transfer
switch will cause the channel number to stop flashing
and cause the frequency to begin flashing, indicating
that rotating the tuning knobs will change the
frequency. Momentarily pressing the CHAN switch will
return the unit to the frequency mode. The standby
frequency will return to what it was prior to entering the
program mode. The unit will automatically return to
the frequency mode if no front panel activity takes
place for 20 seconds.
d. Modes of Operation.
mode of operation is selected by a momentary push
button switch placarded MODE. The operating mode
changes from ADF to ANT to ADF/BFO to ANT/BFO
with each press of the mode switch.
(1) Antenna Mode (ANT).
receiver is in the ANT mode, audio will be present in
the speaker or headphone (if the respective number 1
or 2 ADF receiver audio switch is on), and the RMI
indicator needle that is being used will be parked at
the 90° relative position.
(2) Automatic Direction Finder (ADF) Mode.
When the ADF receiver is in the ADF mode of
operation, the RMI needle or HSI bearing pointer that
is being used will indicate the relative bearing to the
station.
(3) Beat Frequency Oscillator (BFO) Mode.
The BFO is used to hear audio when the tuned station
is a keyed continuous wave (CW) station. The BFO
may be used either in the ANT or ADF mode.
e. ADF Receiver Control Unit (KFS-564A)
Operation.
(1) Turn On Procedure.
1. Avionics Master Switch (overhead
control panel, Figure 2-15) – ON.
2. OFF / VOL / PUSH Knob – Turn
clockwise out of detent, then press to
turn off automatic squelch circuit.
Continue turning knob clockwise until
background
headphones or speaker, ensuring that
3C-46
The ADF receiver
When the ADF
noise is heard in
the receiver is operating, then set
audio volume to desired level. Press
knob again to return unit to automatic
squelch control.
(2) ADF Operating Procedure.
1. Number 1 or Number 2 ADF Receiver
Audio Monitor Switch (audio control
panel, Figure 3C-1) – ON.
2. Mode Switch – Set operating mode as
required.
3. Tuning Knobs – Set desired frequency
or channel.
4. VOL Control – As required.
5. RMI Switch – As required.
3C-24. AUTOMATIC FLIGHT CONTROL SYSTEM
(SPZ-4000).
a. Description.
system is an integrated autopilot/flight director/air data
system.
When the autopilot is engaged and coupled to
the commands of the flight director, the flight control
system will control the aircraft using the same
commands which are displayed on the attitude director
indicator by the flight director command cue. When
the autopilot is engaged and uncoupled from the flight
director commands, manual pitch and roll commands
may be inserted using the Touch Control Steering
(TCS) on the control wheels or the pitch wheel and
turn knob on the autopilot control panel.
When the autopilot is coupled, the flight director
command cue indications on the attitude director
indicator provide a
performance of the autopilot. When the autopilot is not
engaged, the same modes of operation are available
for flight director only. The pilot maneuvers the aircraft
to satisfy the flight director commands, as does the
autopilot when it is engaged.
b. Air Data Computer.
computer located in the forward avionics compartment
provides the altitude information for the pilot's
altimeter, altitude alerter, and transponder.
computer also provides altitude and airspeed hold
function data to the flight control computers. The air
data computer is powered through a 2-ampere circuit
breaker, placarded AIR DATA ENCODER, on the
overhead circuit breaker panel, Figure 2-16. All air
The automatic flight control
means of monitoring
A digital air data
the
The