Communications

Two VHF radios, an audio control panel for each pilot and the tuning controls on the DCPs, MFDs and CDUs. The CVR, the ELT and the static wicks are covered here too. HF, SELCAL, SATCOM and data link are optional.

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What it is

The radios and where to find the controls

Instrument panel with numbered callouts and a legend. Item 2 is the pilot audio control panel and item 12 the copilot audio control panel, at the outer ends of the panel. Items 5 and 9 are the pilot and copilot display control panels on the glareshield. Items 15 and 18 are the left and right multifunction displays.
Instrument panel: audio control panels (2, 12), display control panels (5, 9) and MFDs (15, 18). Tap to enlarge
Center pedestal with numbered callouts and a legend. Items 2 and 6 are the FMS control display units (item 2 optional), item 17 the reversion panel, item 19 the ELT panel and item 20 the cockpit voice recorder panel, near the bottom of the pedestal.
Center pedestal: CDUs (2, 6), reversion panel (17), ELT panel (19) and CVR panel (20). Tap to enlarge
  • The radio communication system groups the radios and their controls. It shares controls with the intercom, audio, PA, navigation and the FMS.
  • Two VHF radios are standard, built so that one failing does not take the other with it. A third VHF is optional.
  • Each VHF is wired to the controls, displays and audio on both sides of the flight deck.
  • The MFD, through the DCP, is the main way to tune. The CDU can tune too, and becomes the main control when the TUNE knob is at CDU ONLY.
  • Frequencies and settings are held in memory, so a power interruption does not change them.
Where to find it
Audio control panels (ACP)One on each side of the instrument panel
Display control panels (DCP)On the glareshield
VHF frequenciesLower part of the left and right MFDs
Reversion selection panel, TUNE knobCenter pedestal
CVR control panelCenter pedestal
ELT switchELT panel on the center pedestal
SpeakersTwo, overhead
Hand microphonesOn each control column
Area microphoneAbove the liquid compass on the windshield center post

Talk and listen

Audio panels, microphones and interphone

Audio control panel. Top row: COM1, COM2, COM3, HF1, HF2, a blank button and PA. Below them two rows of volume knobs: 1 DME 2, 1 ADF 2, MKR, INPH and SPKR, then 1 NAV 2. Bottom: the VOICE, ID, BOTH toggle, the EMER, NORM toggle, the O2 MASK, NORM toggle and the large HDPH knob.
Audio control panel, one for each pilot. Tap to enlarge
Control wheel seen from the pilot seat. On the left horn the master disconnect switch, the trim switch and, behind the horn, the microphone switch marked INPH and TX. On the right horn the AP/FD synchronization switch, the checklist line advance switch and, behind, the transponder ID switch. The red ROLL DISC handle is beside the hub.
Control wheel: the microphone switch behind the left horn, marked INPH and TX. Tap to enlarge
  • From the ACP each pilot listens to the navigation radios, and listens and transmits on VHF, HF (optional), PA and intercom. Its audio goes to that pilot's headset jacks and speaker.
  • Aural warnings, TAWS and TCAS do not pass through the volume controls. The crew cannot turn them down, and warnings are heard with the switches in any position.
  • Each control wheel has a momentary TX/INPH switch. TX transmits on the selected radio. INPH talks on the intercom when interphone is selected off on the ACP.
  • Hand microphones sit on the control columns. Each seat has a headset panel with HDPH and MIC jacks.
  • Two maintenance interphone panels give hot mic contact with the ground crew when it is selected on the ACP. One is on the left of the nose compartment behind the communication access door, the other on the left of the aft equipment compartment.
  • The observer (jump seat) panel is on the PMAT, on the aft side of the left avionics rack, with its own volume control.
ACP switches
SPKRSends the selected audio to your speaker. Turn for volume, push in for speaker off.
INPHIntercom between the crew seats and the service interphone points outside the aircraft
VOICE / ID / BOTHVOICE filters out the station morse identifier, ID gives only the identifier, BOTH gives the two
EMER / NORMLocking toggle. EMER sends the audio straight to the headphones, bypassing the RIU.
O2 MASK / NORMNORM uses the headset boom microphone, O2 MASK the oxygen mask microphone
Headphone audioAlways available

Tuning

Tuning the radios and tuning reversion

Display control panel with the 1/2 button above the TUNE knob, the RADIO button, the MENU and DATA knob with PUSH SELECT in the centre, and the TILT and RANGE knob on the right. Below it, the MFD radio menu: COM1, NAV1, ADF1, HF1, COM3 and COM2 each show the active frequency on top and the recall frequency below, with a cyan box around the COM1 recall frequency. ATC1/TCAS shows the transponder code 7777 in white.
Display control panel and the MFD radio menu it drives. Tap to enlarge
Reversion selection panel with six knobs: LEFT DISPLAYS, EICAS and RIGHT DISPLAYS on top, ATT/HDG, TUNE and AIR DATA below. The TUNE knob has the positions MFD ONLY, NORM, CDU ONLY and COM 1 121.50.
Reversion selection panel: the TUNE knob is bottom centre. Tap to enlarge
  • On the DCP: RADIO brings up the radio menu on the MFD, MENU moves the box to the radio, TUNE sets the frequency (outer knob coarse, inner knob fine), and the button in the centre of TUNE makes it active.
  • 1/2 swaps to the cross-side radios, and their legends turn yellow.
  • With a radio boxed, RADIO opens its submenu: squelch on or off, FREQ SEL for 8.33 or 25 kHz spacing, and TEST.
  • The menu clears 20 seconds after the last use of MENU, DATA or PUSH SELECT.
  • On the CDU, the TUN key opens the TUNE page. Type a frequency or a preset channel (1 to 20) in the scratch pad and push the line select key of the radio.
  • If an MFD fails or is reverted to a compressed PFD, you can no longer tune through it.
  • On essential power only, the procedure sets TUNE REVERSION to CDU ONLY, and COM 2 is in the list of equipment lost. COM 1, CDU 1 and the left DCP are on the left essential bus.
TUNE knob and VHF numbers
NORMTune with the DCP or the CDU. The MFD is the master.
MFD ONLYDCP only. The CDU TUNE page is blank.
CDU ONLYCDU only. The MFD radio menu is blank.
COM 1 121.50Tuning as normal, but COM 1 is forced to 121.50
VHF band118.000 to 136.991 MHz
25 kHz spacing, top of the band136.975 MHz
Before starting enginesL and R audio panels set, REVERSION panel at NORM

Recorders and beacons

CVR, ELT and static wicks

Cockpit voice recorder control panel: a green TEST button with a green light beside it, a HEADSET jack and a red ERASE button.
CVR control panel: TEST with its green light, HEADSET jack and ERASE. Tap to enlarge
ELT panel with a placard reading FOR AVIATION EMER USE ONLY, UNAUTHORIZED OPERATION PROHIBITED, and the ELT switch with the positions ON, ARM and RESET.
ELT switch: ON, ARM and RESET. Tap to enlarge
Line drawing of static wicks: at the top, a wing with wicks on the aileron trailing edge and on the winglet, with two enlarged wicks. Below, the tail with wicks on the rudder, the elevators and the tailcone, with enlarged views of each type.
Where the static wicks are: wing, winglet and tail. Tap to enlarge
  • The CVR is solid state. The recorder, painted bright orange, sits in a crash survivable case in the aft equipment bay. Its control panel is on the pedestal.
  • It starts recording as soon as the aircraft has electrical power. An impact deceleration cuts its power so the recording is not erased.
  • Four channels: observer 1, copilot 2, pilot 3 and the area microphone 4.
  • TEST runs an internal check: the green light means a good test. ERASE works only on the ground, with hydraulics pressurized and the parking brake set.
  • The ELT is a self-contained battery unit at the top left of the aft fuselage. Excessive longitudinal forces set it off by itself.
  • The ELT switch stays at ARM (set before starting engines). ON is for a test or to start the ELT by hand, RESET resets it. While it transmits, ELT ON shows on EICAS.
  • Static wicks discharge static electricity, which cuts radio interference. Check them at the walkaround on both winglets and on the tail.
Key numbers
CVR recording kept120 minutes
CVR audio channels4
Underwater locator battery life6 years
Underwater locator signalUp to 30 days
ELT, VHF121.5 MHz
ELT, UHF243.0 MHz
ELT, third frequency406.025 MHz
Static wicks, total26
On each winglet4
On each wing trailing edge3
On each horizontal stabilizer trailing edge3
On the rudder trailing edge2
On the tailcone2
On the rear navigation light (bullet) fairing2

Messages and failures

EICAS messages and procedures

Table of the communication EICAS messages with their inhibits, meaning and aural alerts: ACARS MESSAGE, AFIS MESSAGE, CABIN CALL, CVR FAIL, DATALINK ATN CPDLC, FANS CPDLC, DATALINK FAIL, FANS 1/A FAIL, DATALINK ACARS, FAX RECEIVED, FDR FAIL, FDR FAULT, LAV CALL, SELCAL HF 1 and 2, SELCAL VHF 1, 2 and 3 and SELCAL DATALINK, all inhibited TO/LAND, and ELT ON with no inhibit.
The communication messages. Many belong to optional equipment. Tap to enlarge
  • All communication messages are cyan advisories except ELT ON, a white status message.
  • They are inhibited for takeoff and landing (TO/LAND). ELT ON is not.
  • CVR FAIL: the voice recorder has a fault. Its procedure has no crew action.
  • CABIN CALL and LAV CALL: a call from the cabin or the lavatory. Each stays on for 10 seconds.
  • ELT ON has no procedure of its own. It is listed with the avionics status messages.
  • Audio System Failure is for a failed ACP: its aim is to bypass the panel. Radio Tuning Failure aims to find the failed tuning source.
  • If the MFDs stop talking to each other (MFD X-TALK FAIL), cross-side tuning is lost.

Optional equipment

HF, SELCAL, SATCOM and data link

Photo of the optional HF radio units installed in an equipment rack, with their cables and connectors.
Optional HF radio installation. Tap to enlarge
  • Everything in this panel is optional and fitted only on some aircraft.
  • HF gives long range communication. Its antenna is part of the fin leading edge. The coupler tunes when you key the transmitter, with a tone in the headset until it is done.
  • HF is tuned from the MFD radio menu or the CDU TUNE page. Its HF CONTROL submenu sets the mode (frequency, emergency channel or maritime channel), simplex or duplex, squelch and power. Simplex, sending and receiving on one frequency, is the usual mode.
  • SELCAL keeps watch on an assigned VHF or HF frequency for you. When your four-letter code arrives, a cyan SELCAL message names the radio and "SELCAL" sounds. Transmitting on that radio clears it.
  • SATCOM is run from the CDU. Data link works over VHF, HF or SATCOM, is controlled from the CDU and carries CPDLC. Only one CPDLC system (FANS or ATN) can be logged on at a time.
  • Weather sent by data link is advisory only.
  • An optional recorder power supply keeps the CVR recording 10 minutes after aircraft power is lost. With it, a nuisance CVR FAIL can show for up to 10 minutes after power up.
Key numbers
HF range2.0 to 29.9999 MHz
HF programmable presets16
HF emergency channels6
HF coupler tuning, maximum6 seconds
HF tuning tone1,000 Hz
FANS INSERT MOD prohibitedWithin 5 NM of sequencing a waypoint
Optional FDR, data keptLast 25 hours

The full module

The slides go through the audio panels, tuning and reversion, the recorders and the failure procedures, then a 10-question test.

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