TM 55-1510-215-10
CHAPTER 3
AVIONICS
SECTION I. GENERAL
3-1. Introduction.
through a 50-ampere circuit breaker to the avionics
power relay which is controlled by the AVIONICS
This
chapter
covers
avionics
equipment
MASTER power switch (fig. 2-22) on the pilot's side of
configuration installed in the aircraft. It includes a brief
the instrument panel. Individual system circuit breakers
description of the avionics equipment, its technical
and associated avionics busses are shown in figure 2-18
characteristics, capabilities, and location.
and figure 2-19. With the AVIONICS MASTER power
switch in the ON position, the avionics power relay is
3-2. Avionics Equipment Configuration.
deenergized and power is applied through two 50-
ampere AVIONICS NO. 1 and 2 circuit breakers to the
The avionics configuration of the aircraft is
individual avionics circuit breakers on the circuit breaker
comprised of three groups of electronic equipment. The
panel (fig. 2-18). In the OFF position, the relay is
communication equipment group consists of the radio
energized and power is removed from avionics
telephone (if installed), interphone, FM liaison (if
equipment. When external power is applied to the
installed), UHF command, VHF command, and HF
aircraft, the avionics power relay is normally energized,
command (if installed) systems.
The navigation
removing power to the avionics equipment.
equipment group provides the pilot and copilot with the
instrumentation required to establish and maintain an
NOTE
accurate flight course and position, and to make an
approach
on
instruments
under
instrument
The avionics master switch and radar
meteorological conditions (IMC). The navigation group
should not normally be turned on,
includes equipment for determining altitude, attitude,
until the generators are on. This will
position, destination, and drift angle. The transponder
help protect the solid-state circuitry.
and radar group includes an identification, position, and
emergency tracking system, and a radar system to
b. AC Power.
AC power for the avionics
locate potentially dangerous weather areas. A ground
equipment is provided by two separately selected
proximity altitude advisory system is also provided.
inverters. The inverters supply 115-volt and 26 volt
single-phase AC power. The inverters are selected by a
3-3. Power Source.
switch located on the left subpanel, placarded
INVERTER LEFT OFF RIGHT. Either inverter may be
a. DC Power. DC power for the avionics equipment
selected for use.
is provided by four sources; the aircraft battery, left and
right generators, and external power. Power is routed
SECTION II. COMMUNICATIONS
3-4. Description.
copilot's seats: and a pushbutton switch located in each
headset microphone jack (pigtail).
The communication equipment group consists of
radio telephone (if installed), interphone, FM liaison (if
b. Controls and Functions.
installed), UHF command, VHF command, and HF
command (if installed) systems.
(1) INPH-XMT MIC switch.
Keys interphone
or selected facility.
3-5. Microphone Switches.
(a) INPH.
When depressed to first
a. Description. Three microphone switches are
detent, keys interpone regardless of audio panel selector
provided for the pilot and copilot: A bi-level microphone
switch position.
switch placarded INPH XMT MIC, located on the pilot's
and copilot's control wheels; a floor switch placarded
(a) XMIT MIC. When depressed fully,
MIC located on the floor in front of the pilot's and
keys facility indicated on audio panel selector switch.
Change 9 3-1
