TM 1-1510-225-10
3A-2
wheels. Refer to Figure 2-22. When the control wheel
microphone switches are pressed, voice audio signals
from the respective microphone are routed to the
transmitter selected by the respective transmitter
selector switch, located on the audio control panel.
b. Cockpit Floor Foot-Operated Microphone
Switch. The copilot is provided with a foot-operated
microphone switch, placarded MIC, located on the
cockpit floor, forward of his respective seat position.
Pressing the foot-operated microphone switch routes
audio signals to the device selected by the copilot's
transmitter selector switch located on the audio control
panel.
c. Microphone Jack Selector Switches. Two
switches, placarded MIC, MIC, NORMAL – OXYGEN
MASK, located on the left and right sides of the
instrument panel, 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
NORMAL position, the headset jack is connected to
the respective audio system. When set to the
OXYGEN MASK position, the oxygen mask jack is
connected to the respective audio system.
3A-6. AUDIO CONTROL PANELS.
a. Description. A dual audio control panel
located on the instrument panel serves both the pilot
and copilot. Its respective 2-amp circuit breaker,
placarded PILOT AUDIO and COPILOT AUDIO,
located on the right sidewall circuit breaker panel
powers each audio control panel, Figure 2-6.
b. Audio
Control
Panel
Controls
and
Functions. Refer to Figure 3A-1.
(1) Pilot's and Copilot’s Receiver Audio
Monitor Switches. The pilot and copilot are each
provided with a set of identical receiver audio monitor
switches, placarded PILOT and COPILOT AUDIO
OFF.
(a) VHF 1 and VHF 2. These switches
connect the user's headset or speaker to the number 1
or 2 VHF communications transceiver audio.
(b) AM / FM . These switches connect
the user’s headset or speaker to the AM/FM
(VHF/UHF) communications transceiver audio.
(c) HF. These switches connect the
user's headset or speaker to the HF communications
transceiver audio.
(d) NAV 1 and 2. These switches
connect the user's headset or speaker to the number 1
or 2 VHF navigation receiver audio.
(e) MKR BCN. These switches connect
the user’s headset or speaker to the marker beacon
receiver audio.
(f) DME 1 and 2. These switches
connect the user's headset or speaker to the number 1
or 2 DME transceiver audio.
(g) ADF. These switches connect the
user's headset or speaker to the ADF navigation
receiver audio.
Figure 3A-1. Audio Control Panel
