Section I. GENERAL
This chapter covers all avionics equipment
installed in the C -12 R aircraft. It provides a brief
characteristics, and locations. It covers systems and
controls and provides the proper techniques and
procedures for operating the equipment. For more
detailed operational information, consult the vendor
manuals that accompany the aircraft loose tools.
3A-2. AVIONICS EQUIPMENT CONFIGURATION.
The aircraft's avionics consist of three groups of
electronic equipment. The communication group
consists of the intercom system, AM/FM (VHF/UHF)
transceiver, two VHF-AM transceivers, HF transceiver,
an Emergency Locator Transmitter (ELT), and a
cockpit voice recorder. The navigation group consists
receivers, Automatic Direction Finder (ADF) receiver,
TACAN receiver, a multi-sensor navigation system, a
radio altimeter system, a gyromagnetic compass
system, an Electronic Flight Instrument System (EFIS),
and a digital integrated flight control system. The
transponder and radar group consists of a weather
radar system, transponder, and a servoed encoding
altimeter indicator. The transponder and radar group
includes an identification, position, and emergency
tracking system, and a radar system to locate
potentially dangerous weather areas. A Ground
Proximity Altitude Advisory System (GPAAS) is also
3A-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
2-27, Sheet 1 and Table 2-7.
b. AVIONICS MASTER PWR Switch. A switch,
placarded AVIONICS MASTER PWR OFF, located on
the pilot's subpanel, controls power to the avionics
(1) OFF. In the OFF position, power from
the 5-amp circuit breaker, placarded AVIONICS
MASTER, located on the right sidewall circuit breaker
panel, Figure 2-6, energizes the avionics relay,
removing power from the avionics buses.
(2) On. With the switch in the 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.
Power. Two static
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
Section II. COMMUNICATIONS
The communications equipment group consists
of an intercom system connected to a dual audio
control panel serving both the pilot and copilot, which
interfaces with VHF, UHF, and HF transceivers and
provides reception of audio from VOR, localizer,
marker beacon, TACAN/DME, and ADF receivers.
3A-5. MICROPHONES, SWITCHES, AND JACKS.
Boom and oxygen mask microphones can be
used in the aircraft.
a. Control Wheel Microphone Switches. The
pilot and copilot are each provided with control wheel
microphone switches, placarded MIC, located behind
the outboard handgrip of their respective control