PS Engineering Audio Panel
and other Audio Switchology
Maj. Jeff Knutson
PS Engineering Audio Panel
 Additional
features for CAP operations
 More complicated than older units like KMA-24’s
 May be confusing if crew unfamiliar with
operation
Features
 Can
isolate pilot from rest of crew
 Useful
in searches with heavy ATC or CAP
communications
 Can
isolate front seat from back seat
 Can have pilot talking on different frequency than
observer
 Can swap frequencies
 Sometimes
inadvertently!
Operation
Marker
Sensitivity
Intercom
volume Switch (3 position)
 Marker
Beacon Lights (same as other units)

High
Does not affect radio volume

Low
Push
in to turn audio panel on/off
Test (lights)
Intercom Modes
 ISO
pilot hears radios – Isolated from crew
Observer and scanners have intercom
Observer hears Com3
Only
Intercom Modes
 All
Everybody
hears everything
Intercom Modes
 Crew
(i.e. front seat)
Pilot and Observer hear radios
Front seat isolated from rear seat
Rear seats have separate intercom and no radios
COM1
 Activates
audio for communication radio 1
Operation just like other audio panels
Green light illuminates when activated
COM2
 Activates
audio for communication radio 2
Operation just like other audio panels
Green light illuminates when activated
NAV1, NAV2, MKR, ADF, DME
 Activates
audio for selected radio
 Operation
just like other audio panels
 Green light illuminates when activated
ICS (Intercom)
 Opens
intercom between pilot and observer during
split modes
 Green light illuminates when activated
 If not selected when split mode is selected pilot
will again be isolated!
COM3
 Activates
 Green
audio for CAP FM radio
light illuminates when activated
SPR (Speaker)
 Turns
on cabin speaker
 Operation
just like other audio panels
 Green light illuminates when activated
Transmitter Select Knob
 Selects
on which radio the pilot and
observer will transmit
Transmitter Select Knob
 Pilot:
COM1
 Observer: COM1
Transmitter Select Knob
 Pilot:
COM2
 Observer: COM2
Transmitter Select Knob
 Pilot:
COM3 (CAP FM)
 Observer: COM3 (CAP FM)
Transmitter Select Knob - Split
 Pilot:
COM1
 Observer: COM2
 Don’t
forget about ICS button!
Transmitter Select Knob - Split
 Pilot:
COM1
 Observer: COM3
Transmitter Select Knob - Split
 Pilot:
COM2
 Observer: COM3
Transmit Light
 Illuminates
when crewmember is
transmitting on selected radio
Swap Light
Look out for
this!
 Illuminates
when swap mode is selected on control yoke
 Effects determined by transmitter select switch position
 Swap button is the same type and is right next to the mic
button
 Very
easy hit hit accidentally
 Verify swap light mode when transmitting
Swap Light Effects
 Toggles
between COM1 (no light) and
COM2 (light)
Swap Light Effects
 Toggles
between COM2 (no light) and
COM1 (light)
Swap Light Effects
 No
swap
Swap Light Effects
 Pilot
COM1, Observer COM2 (no light)
 Pilot COM2, Observer COM1 (light)
 Again,
in split mode, if ICS not selected pilot will
be isolated
Swap Light Effects
 Pilot
COM1, Observer COM3 (no light)
 Pilot COM3, Observer COM1 (light)
Swap Light Effects
 Pilot
COM2, Observer COM3 (no light)
 Pilot COM3, Observer COM2 (light)
DF Audio Switch
 Note
there is
no ELT DF
button on
audio panel
 How does the
crew hear
ELT’s?
Remote panel
switch
DF Audio Switch
 Remote
DF Audio
toggle must be
switched up to the
ON position
 Turning
up the
volume on the DF
unit won’t help if
the DF audio is
switched OFF
Problems
 Pilot
can’t hear the Observer. What could cause this?
 Audio
panel turned off
 Intercom in ISO mode
 Transmitter select switch in split mode and ICS button not
activated
 ATC
has been quiet, and now they don’t reply to my
calls
swap mode – might have hit it on the last transmission
and have been listening to the wrong frequency for the last 15
minutes
 Check
Problems
 The
scanner can’t hear the front seat crew or
radios?
 Intercom
in Crew mode
 Headset is unplugged
 The
crew can’t hear the ELT beacon
 Volume
on DF unit is too low
 The remote DF audio switch is turned off