TM 1-1510-225-10
3B-4
(25) Pilot’s VOICE / BOTH / RANGE Switch.
(a) VOICE – Kills range; allows voice.
(b) BOTH – Allows both voice and range.
(c) RANGE – Kills voice, allows 1020 Hz
range tone.
(26) AUDIO EMER / NORM Switch.
(a) EMER – Allows reception of all audio
in headphones in the event of failure of audio amplifier.
(b) NORM – Allows normal operation of
the audio amplifier.
(27) Pilot’s AUDIO SPKR / OFF Switch –
Routes audio to overhead speakers.
(28) Pilot’s Transmitter Selector – Select
COMM 1, COMM 2, HF, MBND RADIO, INTP, or
CABIN.
3B-7. VHF COMMUNICATIONS COMM
1
AND
COMM 2.
Refer
to
Chapter
3,
Paragraph
3-4,
for
information on the VHF Communication Radios.
3B-8. HF COMMUNICATIONS OSA .
Refer to Chapter 3, Paragraph 3-3, for HF
descriptions and operation information.
3B-9. SATCOM COMMUNICATIONS.
a. Description. The AN/ARC-210 SATCOM
Radio
is
installed
in
the
C-12T3
for
V/UHF
communication.
b. Power to the AN/ARC-210 is provided
through a 7½ -ampere circuit breaker, placarded
MBND RADIO, located on the right hand circuit panel.
c. Control and Operations. Control of the
ARC-210 is through the FMS-800 CDU. Refer to
Paragraph
3B-19t
for
control
and
operating
procedures.
3B-10. EMERGENCY LOCATOR TRANSMITTER.
a. Description. An automatic or manually
activated Emergency Locator Transmitter (ELT) is
located
in
the
right
side
of
the
fuselage
at
approximately FS 340.00. The associated antenna is
mounted on top of the aft fuselage at approximately
the same location. An access hole with spring-loaded
cover is located in the fuselage skin adjacent to the
transmitter, enabling a downed pilot to manually
initiate or terminate operation, or reset the ELT to an
armed mode. The transmitter contains an impact G
switch that automatically activates the transmitter
following a 3 G to 7 G impact along the flight axis of
the aircraft. When activated, the ELT will radiate
omnidirectional RF signals on the international distress
frequencies of 121.5 MHz and 243.0 MHz. The
radiated signal is modulated with an audio swept tone.
Internal batteries provide transmitter operation for a
minimum of 48 hours.
b. Switches and Functions.
(1) ARM . Establishes readiness state to
start automatic emergency signal transmissions when
the force of impact exceeds a preset threshold.
(2) ON. Turns set on initiating emergency
signal transmissions.
(3) OFF. Turns set off.
3B-11. COCKPIT
VOICE
RECORDER
SYSTEM
OSA .
a. Introduction. The Cockpit Voice Recorder
(CVR) system records all voice signals on a
continuous-loop magnetic tape for a maximum period
of 30 minutes. Voice recordings in excess of
30 minutes are automatically erased. The voice inputs
may be either transmitted or received signals
originating from the aircraft communications system or
the remotely mounted cockpit area microphone
mounted in the glareshield. The CVR system is a
modular system comprised of three modules, the
recorder, the control unit, and a remote microphone.
The recorder is a vibrator mounted unit housed in an
international orange case located in the unpressurized
aft fuselage area. The recorder contains the recording
unit and associated electronics. An impact switch,
mounted in the aft avionics c ompartment, controls
power to the voice recorder. If the impact switch is
subjected to a 2.5 G shock, the recorder is electrically
disconnected to prevent further recording and erasure
or voice communications. A red light located on the
impact switch case when illuminated indicates the
switch has been actuated. Pressing the reset button
located adjacent to the impact switch light causes the
light to extinguish and restores power to the voice
recorder. The control unit is located on the extended
pedestal, and houses the microphone preamplifier,
test switch, erase switch and a meter. The remote
microphone module is located in the glareshield
outboard of the Warning Annunciator panel. The CVR
system receives 115 Vac power through a 1-ampere
circuit breaker, placarded RECORDER POWER /
