Section I. GENERAL
This chapter covers all avionics equipment
installed in the C-12 T3 aircraft and provides a brief
characteristics, and locations. If the item is common to
all three aircraft, C-12R, C-12T3, and C-12F3, you will
be referred to the appropriate paragraph in Chapter 3.
For more detailed operational information, consult the
vendor manuals that accompany the aircraft loose
3B-2. AVIONICS EQUIPMENT CONFIGURATION.
The aircrafts avionics consist of three groups of
electronic equipment. The communication group
consists of the intercom system, AM/FM (V/UHF)
SATCOM transceiver, two VHF-AM transceivers, HF
transceiver OSA , an Emergency Locator Transmitter
(ELT), and a cockpit voice and data recorder OSA .
Automatic Direction Finder (ADF) receiver, Distance
Measuring Equipment (DME), Global Positioning
Systems (GPS) FMS 1-FMS-800 and FMS 2-KLN
90B, radio altimeter, Electronic Flight Instrument
System (EFIS), Automatic Flight Control System
(AFCS), and a gyromagnetic compass system. The
transponder and radar group consists of a weather
radar system, transponder, Traffic Alert and Collision
Avoidance System (GCAS).
3B-3. POWER SOURCE.
a. DC Power. DC power for the avionics
equipment is provided from four sources: the aircraft
battery, left and right generators, and external power.
Power is routed through two 50-ampere circuit
breakers to the avionics power relay, which is
controlled by the AVIONICS MASTER PWR switch
located on the pilot's subpanel, Figure 2-5. Individual
system circuit breakers are shown in Figure 2-6 and
the associated avionics buses are shown in Figure
2-28 and Table 2-8.
(1) Avionics Master Power Switch. A switch
placarded AVIONICS MASTER PWR OFF, located on
the pilot's subpanel, controls power to the avionics
(a) Off. In the aft (off) position, power
AVIONICS MASTER, located on the right sidewall
circuit breaker panel, Figure 2-6, energizes the
avionics relay, removing power from the avionics
(b) On. With the switch in the UP (on)
position, the avionics power relay is de-energized and
power is applied to the avionics buses.
If the AVIONICS MASTER PWR switch fails
to operate, provide power to the individual
avionics circuit breakers by pulling the
AVIONICS MASTER, located on the right
sidewall circuit breaker panel.
(2) DC Auxiliary Bus. DC power may be
applied to an independent bus for isolated operation of
the UHF and COMM 1 radios, pilots audio system,
and instrument indirect lights. Use of the auxiliary bus
is independent of the battery master switch position,
but is controlled by a two position ON / OFF switch,
placarded DC AUX BUS, located under the gang bar
with the battery and generator switches. Placing this
switch in the ON position will provi de battery power to
the auxiliary bus for operation of the previously
mentioned equipment should an electrical emergency
such as a dual bus failure occur in-flight, or if operation
of the equipment is desired during pre/postflight
inverters supply 400 Hz single-phase 115-volt and
26 Vac electrical power to the avionics equipment.
The inverters are controlled by a switch placarded
INVERTER NO 1 / OFF / NO 2, located on the pilot's