inverters are controlled by two three-position switches
placarded 3f AC CONTROL, # 1 and # 2 INV, RESET
- ON - OFF, located on the mission control panel (fig. 4-
Section II. COMMUNICATIONS
The communications equipment group consists of
an intercom system connected to individual audio control
panels for the pilot and copilot which interface with VHF,
UHF, BU VOW, VHF-FM, and HF transceivers, and
provide reception of audio from VOR, localizer, marker
beacon, TACAN/DME, and ADF receivers.
MICROPHONES, SWITCHES, AND JACKS.
Boom and oxygen mask microphones can be
utilized in the aircraft.
Control Wheel Microphone Switches. The pilot
and copilot are each provided with bi-level microphone
switches placarded MIC, INTPH - XMIT, located behind
the outboard handgrip of their respective control wheels
(fig. 2-24). When the control wheel microphone
switches are depressed to the first level (INTPH
position), voice audio signals from the respective
microphone are routed to the intercom system (the
position of the transmitter-intercom selector switch is
When the control wheel microphone switches are
depressed to the second level (XMIT position), voice
audio signals from the respective microphone are routed
to the transmitter selected by the transmitter-intercom
selector switch (located on the respective audio control
panel, fig. 3-1).
b.Cockpit Floor Foot-Operated Microphone Switches.
The pilot and copilot are each provided with a foot-
operated microphone switch, placarded MIC, located on
the cockpit floor, forward of their respective seat
Depressing the foot-operated microphone switches
routes audio signals to the device selected by the
transmitter-intercom selector switch located on the
respective audio control panel (fig. 3-1).
Microphone Jack Selector Switches. Two
switches, placarded MIC, HEADSET OXYGEN MASK,
located on the left and right sides of the instrument panel
(fig. 2-18), provide a means of selecting which
microphone jack is connected to the audio system.
When the pilot's or copilot's switch is set to the
HEADSET position, the headset jack is connected to the
respective audio system. When set to the OXYGEN
the oxygen mask jack is connected to the respective
AUDIO CONTROL PANELS.
Description. Separate identical audio control
panels (fig. 3-1), located on the left and right subpanels
(fig. 2-8), are provided for the pilot and copilot. Each
audio control panel is powered by its respective 2-
ampere circuit breaker placarded AUDIO PILOT or
AUDIO COPIL, located on the overhead circuit breaker
panel (fig. 2-9).
b.VHF-FM/VHF-Alternate Communication Switch Panel.
An alternate communication switch panel with three
alternate-action (push on, push off) switches, located on
the pedestal extension (fig. 3-2), allows position 2 of the
audio control panel transmitter-selector switch to be
connected to an alternate transceiver.
communication selector switch. The center alternate-
action (push on, push off) alternate communication
switch is placarded FM, AM. When the switch is
depressed, either FM or AM will be illuminated. When
the switch is set to the FM position, position number 2 of
the transmitter selector switch (audio control panel, fig.
3-1) and number 2 radio monitor control will be
connected to the VHF-FM (SINCGARS) transceiver for
both transmit and receive functions. When the switch is
set to the AM position, position number 2 of the
transmitter selector switch (audio control panel, fig. 3-1)
and the number 2 radio monitor control will be connected
to the VHF-AM number 2 transceiver for both transmit
and receive functions.
communication monitor switch. The pilot and copilot are
each provided with an alternate action (push on, pull off)
alternate communication monitor switch, located on the
left side (pilot's switch) or right side (copilot's switch), of
the alternate communication switch panel (pedestal
extension, fig. 2-14). Both switches have illuminated
placarding which reads MON, ON - OFF. When the
switch is depressed, either
ON or OFF will be
illuminated. When either of the switches is set to ON
and the center switch is set to FM, the VHF-AM number
2 audio will be heard in addition to the FM audio. The
FM audio cannot be monitored when the center switch is
set to AM. The monitored audio volume will not be
controlled by the number two radio monitor control.