P139-HD Audio System User Manual
GA063-3 Rev G 08/25/2015
Page 12 of 35
6. Audio System Emergency Isolation Mode Function
6.1. Description
The Audio System Emergency Isolation Mode Switch allows the pilot(s) to bypass the Audio System and
connect directly to the COM radio(s) and aircraft warning audio. Emergency Isolation Mode activates
automatically if the G13000/G13160 Audio Router loses power. If the audio system still has power while
in Emergency Isolation Mode, Pilot and Co-pilot share a fixed-volume ICS line and individual Voice
Recorder audio outputs.
Emergency Isolation Mode is controlled by two pins on the power connector (J5 on G13000, J7 on
G13160) labelled COM1DIR and COM2DIR for Pilot/COM1 and Co-pilot/COM2 respectively. For a
headset to be in normal mode, the Audio Router must have power, be operating normally and the
COMnDIR pin must be grounded. If the router does not have power or the COMnDIR pin is not grounded,
the router will be in Emergency Isolation Mode.
The Pilot and Co-pilot G13115 or G13116 control panels have a locking EMERG/NORMAL toggle switch,
which grounds the COMnDIR pin when in the NORMAL position. To enable Emergency Isolation Mode,
pull the toggle and move the switch to the EMERG position. This will disconnect the COMnDIR pin from
ground.
The Pilot EMERG/NORMAL switch MUST be connected to the audio router. If the Co-pilot position will
never be used to fly the aircraft the Co-pilot/COM2 Emergency Isolation Mode control line may be
grounded to permanently enable Normal mode while the Audio Router has power.
The audio system operates as follows depending on switch position:
NORMAL
In the NORMAL position, the Audio System operates as described in the rest of this document.
EMERG (or loss of power to audio system)
In the EMERG position the following occurs:
1.
The
Pilot’s microphone and earphone audio is disconnected from the normal audio
system circuits. Mic audio is directly connected to the COM1 radio port transmit audio
and Earphone audio is connected to the COM1 and XCVR11 radio port receive audio for
aircraft warnings and other important audio.
2.
The
Pilot’s transmit PTT Keyline and dedicated COM1 transmit PTT keyline are directly
connected to the COM1 radio port transmit keyline output.
3.
If the audio system still has power the Pilot headset is connected to a fixed-volume
emergency intercom bus between Pilot and Co-pilot headset ports. The emergency ICS
is keyed by the Pilot ICS PTT keyline. ICS VOX is disabled, and there is no sidetone.
4.
If the audio system still has power the Pilot headset audio is duplicated on the XCVR11
transmit audio for use in voice recorder systems.
For the Co-pilot position, the Co-pilot EMERG/NORMAL switch performs the same functions between the
Co-pilot Headset, COM2 and XCVR20 radio ports.
If the P139-HD has power, other Headset Ports will work as normal when the pilots are in Emergency
Isolation Mode , except they will not be able to communicate with the Pilot, COM1 and XCVR11 ports
and/or Co-pilot, COM2 and XCVR20 ports depending on which pairs are bypassed. A loss of power to the
P139-HD will automatically place the system in Emergency Isolation Mode for Pilot and Co-pilot.
