Gulfstream G550 User manual

COMMUNICATIONS
2A-23-10: General
The Gulfstream G550 communications system provides the flight crew audio links within
the aircraft, and radio links to other aircraft and ground stations. Transmitter and audio
reception selections are made using pushbuttons on the audio panels installed at the
pilot, copilot and observer stations. (See Figure 1.)
The communications system is divided into the following subsystems:
•2A-23-20: Audio Panels
•2A-23-30: Voice Communication Systems
•2A-23-40: MCDU and CCD Radio Tuning
•2A-23-50: Selective Calling System
•2A-23-60: Cockpit Voice Recorder System
•2A-23-70: Emergency Locator Transmitter
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Communications System
Components
Figure 1
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2A-23-20: Audio Panels
1. General Description:
Three AV-900 audio panels are installed in the cockpit: one at each pilot seat and
one at the observer station. All panels are identical, and a typical panel is shown
in Figure 2. All three audio panels are linked over redundant digital buses. Digital
busses carry microphone transmit and audio receive selection data to the
Network Interface Modules (NIMs) in the Modular Radio Cabinets (MRCs). (The
NIMs translate voice analog audio into digital data). The MRCs contain the
communication and navigation radios (COM, NAV, ADF, DME and XPDR), a non-
volatile memory that stores radio and audio configuration data, and an internally
mounted cooling fan. Both the analog third dual function NAV / COM radio (NAV/
COM 3) and the High Frequency (HF) radios are located outside of the MRC and
interfaced to the audio panels through ARINC-429 connections to the MAUs.
The audio panels are configured to hold up to ten (10) rectangular transmit (mic)
buttons and a combination of up to twenty (20) round audio reception button
selections or square feature selections. Only one transmit selection may be made
at a time, and selection of the transmit button will automatically activate the audio
reception button for the associated radio. The audio panels at the pilot and copilot
stations provide an output of eight (8) watts to the respective cockpit speaker on
the overhead. The observer audio panel does not have the wiring installed for a
speaker output. Transmit audio output from each panel is also provided to the
Cockpit Voice Recorder (CVR) system.
The AV-900 audio panels provide the following functions to the flight crew:
•Ten available rectangular transmit button selections
•Twenty available round audio reception button selections
•Three function button selections including selected calling (SELCAL)
•Volume control
•Emergency volume control
•LCD display
•Warning audio outputs
•Volume control
•Cockpit speaker output
•Continuous transmit audio output to CVR
NOTE:
For a detailed description of the Audio Control Panels,
see Section 2B-09-00 of this manual.
2. Controls and Indicators:
NOTE:
For a complete description including graphics
illustratingACP functions, see Section 2B-09-00 of this
manual.
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A. Transmit Button Selections:
The ten rectangular transmit buttons on the audio panel illuminate green
when selected. Selection of a transmit button will automatically select the
corresponding audio reception.
(1) COM 1, COM 2 and COM 3 selections transmit voice or data over
the selected VDR / VHF radio, tuned with the MCDU.
(2) HF 1 and HF 2 selections transmit voice over the selected HF radio,
tuned with the MCDU.
(3) SAT selection transmits voice or data over the SATCOM installation
linked to the International Maritime Satellite Organization
(INMARSAT) network. SATCOM communications are selected with
MCDU entries or with a handset installed in the cockpit center
console.
(4) PA selection transmits voice to the cabin speaker system. When this
option is selected, the cabin stereo audio system is automatically
muted. Only one pilot crew member may use the PA function at a
time.
(5) CABN selection allows communication over the cabin interphone
system.
(6) FONE selection allows MAGNASTART telephone operation
including call pick-up, hang-up, hold, transfer and conference calls.
Telephone dialing is accomplished using the MCDU or cockpit
handset.
(7) CONF selection is used to participate in conference calling.
B. Audio Reception Button Selections:
Up to twenty round audio reception buttons can be installed on the audio
panel below the transmit buttons. When one of the audio sources is
selected, the button is internally illuminated green. Audio volume of the
selected source is controlled by rotating the button.
Reception buttons are provided for identifying navigational radio sources,
monitoring the cockpit voice recorder, cabin calls, selecting the cockpit
speakers on or off, adjusting headphone volume, internal communications
(ICS) on or off, communicating with the maintenance interphone panels at
the nose and tail of the aircraft, controlling volume of the audio panel
transmitted sidetone, and selecting a voice activated microphone feature.
C. MIC Selections:
Each audio panel interfaces with a corresponding jack box that provides
plug-ins for a hand microphone, boom microphone and a headset. A
microphone jack box is also mounted on each yoke column. The oxygen
mask microphones are wired independently adjacent to the oxygen supply
tube.AMIC pushbutton on the audio panel selects either the boom or mask
microphone. Pushing in the selector transmits via the boom mic; oxygen
mask mic is selected with the button out and the onside cockpit speaker is
activated. For either of these microphones, the pilot and copilot transmit
using the yoke mounted mic switches (forward for the audio panel selected
transmitter of aft for aircraft interphone) or by using the voice activated mic
function (VOX) described below. The observer transmits with a similar up
and down transmit select button at the observer station or VOX option.
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The hand held microphones may be used at any time regardless of the
MIC pushbutton selection.
The EMER “backup” pushbutton on ACP 1 (pilot) and ACP 2 (copilot)
controls a relay within the respective ACP that selects normal digitized
audio panel operation when pushed in, or selects a direct analog wire
connection from headsets and microphones to VHF COM #1 when pulled
out. The pushbutton rotates to control volume. The EMER pushbutton can
be used for communication over VHF COM #1 in the event of a failure of
the ACP or NIM. There are no direct analog connections from ACP 3 to
VHF COM #1.
In the event of an aircraft electrical failure that results in only the main
aircraft batteries available for powering the Essential DC buses, all three
digital audio panels remain operative, and communications are possible
from any of the ACPs over VHF COM #1. If only the aircraft emergency
batteries are available, only ACP 1 at the pilot position is powered by the
emergency DC bus. When Essential DC buses are lost, ACP 2 is not
powered, however the relay controlled by the EMER pushbutton on ACP 2
will switch to a direct analog wire path connecting the copilot headphones
and microphone to VHF COM #1, enabling both crew members
communicate over the radio.
NOTE:
Only the #1 VHF NAV and COM radios are available
on emergency battery power (NIM #1 and XPDR #1
are also available). These radios are tuned using
MCDU #3 that is powered by the emergency batteries
and has a direct ARINC-429 connection to the #1 NAV
/ COM radios. Only the pilot’s cockpit speaker is
available in emergency battery mode.
NOTE:
Selecting EMER on any ACP will not tune the VHF
radios to the 121.5 mHz emergency frequency.
D. ON / OFF Feature Selections:
Three square on / off feature selectors are installed on the audio panel. The
square selectors are illuminated green when the option is actively selected:
•ID turns on or off Morse code identifiers when monitoring the audio
of navigational radios
•MUTE eliminates the audio of the marker beacon receiver if
selected on with the round audio reception pushbutton
•SELCAL displays the selcal code address of the aircraft. Upon
receipt of a selcal message, the selcal indicator light and the light
within the reception button of the radio detecting the message will
flash, and a message annunciation will appear in the LCD window.
Pressing the selcal selector or selecting and keying the transmitter
of the radio carrying the incoming message will cancel the selcal
alert indications. See the selcal discussion section below.
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E. Audio Panel Volume Control:
The large round knob on the audio panel labeled SET controls the overall
volume setting of the selected audio inputs to the panel. A numerical value
associated with the set volume level is displayed in the LED indicator to the
left of the knob when the knob is used.
F. LCD Display:
The LCD display provides an alphanumeric readout of information related
to the operation of the audio panel. The display annunciates the current
transmit selection, an numerical value for volume settings, a notification of
a stuck microphone, indicates the source of an incoming selcal message
and displays faults associated with the panel.
G. Cockpit Speakers:
The pilot and copilot cockpit speakers are powered by the respective audio
panels. There is no provision for an observers speaker. Each of the two
speakers is selected on with the SPKR audio button and volume controlled
by rotating the button. There are five source inputs in the NIM for the
annunciation of aural messages over cockpit speakers. These messages
includes EGPWS and TCAS warnings, autopilot disconnect warnings,
tones associated with CAS messages, and fire warnings. Safety critical
aural warnings, cautions and advisories that are required to be announced
over cockpit speakers cannot be muted and are annunciated even if the
speaker is selected off, and are therefore not controlled by the speaker
volume control. Volume levels of safety critical aural annunciations are set
in the initial audio system configuration.
NOTE:
The APU fire warning bell in the nose wheel well uses
the speaker amplifier of the left (pilot) audio panel.
When the APU fire bell is active (fire detected with
aircraft on the ground - weight-on-wheels) only the
copilot side cockpit speaker is available for audio.
H. Side Tone Adjustment (ST):
The ST rotary button sets speaker sidetone level to eliminate feedback
from the speaker to the headset. The sidetone level is indicated in the LED
window. The button is illuminated and the LED indication active only for five
(5) seconds after adjustment. The sidetone may be adjusted with or without
speaker sound on.
I. Voice Activated Microphone (VOX):
Selecting the VOX feature enables transmissions (both radio and ICS or
Cabin) to be made without using the press to talk switches on the yoke or
hand microphones. The sensitivity of the voice activation is controlled by
rotating the selector, with the sensitivity level displayed in the LED indicator
(the higher the number the higher the sensitivity).
3. Controls and Indications
See Figure 2.
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A. Circuit Breakers (CBs):
The audio panels are protected by the following CBs:
Circuit Breaker Name: CB Panel: Location: Power Source:
PILOT ACP LEER D-17 L EMER 28v DC Bus
COPILOT ACP REER D-6 R ESS 28v DC Bus
OBSERVER ACP REER D-7 R ESS 28v DC Bus
B. Crew Alerting System (CAS) Messages:
The following CAS message is associated with the Audio Control Panels:
Area Monitored: CAS Message: Message Color:
ACP ACP 1-2 Fail Amber
ACP ACP 3 Fail Blue
4. Limitations:
A. Flight Manual Limitations:
The flight crew shall wear headsets with acoustical protection when
operating the aircraft in the “green” configuration.
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