Comm.10 Communications-Description and Operation General The MD-11communications system consists of the following: VHF communications system. HF communications system. Communication Radio Panels (CRP). Audio Control Panels (ACP). Flight interphone system. Service interphone/call system. Selective Calling System (SELCAL). Cockpit Voice Recorder (CVR) system. Satellite Communications (SATCOM) system, if installed. Aircraft Communications Addressing And Reporting System (ACARS), if installed. Static dischargers on the trailing edges of the wing and tail surfaces dissipate static electricity that could interfere with communications and navigation. The wingtip and winglet dischargers also protect the aft wingtip lenses from lightning strike. VHF Communications System The VHF communications system consists of three separate, identical systems, designated VHF1, VHF2 and VHF3. All of the three systems operate separately or simultaneously. The systems provide short-range line-of-sight communications in the 118.000 to 136.975-MHz frequency range. This allows communications between the airplane and ground and/or other airplanes. The selection for the VHF communications system is controlled from any of three Communication Radio Panels (CRP). HF Communications System The HF communications system consists of two separate, identical systems, designated HF1 and HF2. The systems provide long range communications between the airplane and ground and/or other airplanes in the 2.000 to 29.9999 MHz in wide range or 2.8000 to 23.9999 MHz in narrow range on channels spaced at 1.0 KHz or 100 Hz. MD-11 - Communications Page 1
The frequency selection for the HF communications system is controlled from the CRP. HF radios must not be operated during airplane refueling operations due to the possibility of arcing. Communication Radio Panel Three Communication Radio Panels (CRP) are installed on the aft pedestal to provide tuning of the communications systems. The interface between CRPs allows tuning of the communications radios from any panel. Pushing one of the five radio select switches on the panel (VHF1, VHF2, VHF3, HF1 or HF2), illuminates the selected switch, and the associated ACTIVE and STBY frequencies are displayed. New frequencies are placed in the STBY memory and transferred to the ACTIVE mode by use of the transfer button. The three CRPs can be used simultaneously, provided radio selection (VHF1, VHF2, VHF3, HF1, HF2) differs from another CRP. Only one radio may be selected on an individual CRP. Audio Control Panel Two Audio Control Panels (ACP) are installed on the aft pedestal and one is installed at the observer station. The ACPs provide the following functions: Communication radio transmit and volume control. Navigation radio ident and volume control. Flight/service interphone transmit and volume control. Transmitting can be done using a handheld, boom, or oxygen mask microphone. The handheld microphone cannot be used for the PA system. Flight Interphone System The flight interphone is controlled by three ACPs. Jacks for the boom and handheld microphone are installed at the Captain's, First Officer's, and right Observer's stations. A flight interphone jack is installed at the ground power receptacle, the nose landing gear, and in the avionics compartment. In addition, the oxygen masks in the cockpit each include a microphone which automatically switches from the boom microphone to the mask microphone when the oxygen mask PRESS TO TEST AND RESET lever is pushed, or when the oxygen mask stowage box doors are opened. Automatic transfer from mask microphone back to boom microphone is initiated by closing the left mask stowage box door and pushing the PRESS TO TEST AND RESET lever. MD-11 - Communications Page 2
Flight interphone transmission may be accomplished by using any of the following: The radio Push To Talk (PTT) switch on the outboard horn of either control wheel with INT MIC selected. The INT switch on the ACP. The PTT switch on each hand microphone with INT MIC selected. Radio PTT switches, one each on the Captain and First Officer's lighting control panels with INT MIC selected on the ACP. The cockpit speakers are muted as follows: Keying the Captain s hand, boom, or mask microphone for radio or interphone mutes the Captain s speakers. Keying the First Officer s hand, boom, or mask microphone for radio or interphone mutes the First Officer s speakers. Keying any microphone or cockpit handset for service interphone does not mute the speakers. Keying the Observer s hand, boom, or mask microphone for radio or interphone does not mute the Captain s or First Officer s speakers. Service Interphone/Call System The service interphone/call system allows communications between the cockpit and courier s stations and between the cockpit and maintenance service areas. The service interphone/call panel is installed on the forward overhead panel in the cockpit. On the freighter configuration, a single COURIER switch is located on the forward overhead panel. The following service interphone operations are possible through the handset: The cockpit can call the courier station or the maintenance service area. The courier s station can call the cockpit. Maintenance interphone jacks are located at various locations on the airplane. These jacks permit communications between these areas and the cockpit. The call system provides both visual and/or aural signals that do the following: Alert the flight crew of a call from the courier s station or ground maintenance. Alert courier s station or ground maintenance of a call from the flight crew. A call from the ground power panel to the cockpit causes the following: Actuation of a chime in the cockpit. MD-11 - Communications Page 3
Illumination of MECH on the ACP MIC/MECH switch. Illumination of CALL on the service interphone/call panel MECH/CALL light. The call system can be reset from any station or the cockpit by pushing the CALL RESET button. The system resets automatically when the handset is returned to its hanger or a microphone is keyed on the appropriate interphone. Selective Calling (SELCAL) System Selective Calling (SELCAL) operates in conjunction with the VHF and HF systems to provide visual and aural indications that the airplane is being called by a ground station. When a ground station calls the airplane, the applicable CALL light on the ACP flashes and the Central Aural Warning System (CAWS) sounds a chime. This chime is inhibited during takeoff or landing. When the call is acknowledged, the system is automatically reset by pushing the MIC/CALL light on the ACP and keying the radio PTT on the associated control wheel, or ACP. The radio volume control knobs on the ACP permit volume control of the receivers without affecting SELCAL system operation. In the event the SELCAL system fails, the VHF and the HF communications systems continue to operate normally. Cockpit Voice Recorder The Cockpit Voice Recorder (CVR) system automatically records all interphone and radio communications initiated and received by the flight crew. The recorder records four channels of information simultaneously as follows: Channel 1 records the cockpit handset receiver on service interphone. Channel 2 records the First Officer's headset and handheld, oxygen mask, or boom microphone audio. Channel 3 records the Captain's headset and handheld, oxygen mask, or boom microphone audio. Channel 4 records the area microphone in the voice recorder panel. The recorder, including an underwater locating beacon, is installed in the aft fuselage. It preserves the last 30 minutes of sound and communication, unless erased. MD-11 - Communications Page 4
The Cockpit Voice Recorder panel is on the forward overhead panel. It contains a monitor microphone, a HEADSET or HEADPHONE jack, and controls for testing the recorder and erasing previous recordings. The ERASE button is interlocked through the parking brake switch and a ground sensing relay so that erasure is possible only when the airplane is on the ground with the parking brake set. Satellite Communications (SATCOM) If installed, the Satellite Communications (SATCOM) system provides air/ground voice and data communication. The system uses satellites (via SATCOM antenna) and ground stations to relay transmissions to and from the airplane. The Satellite Data Units (SDU) on board the airplane process signals from antennas and interface with the Multifunction Control Display Unit (MCDU), ACARS, Audio Management Unit (AMU), and Cabin Telecommunication Unit (CTU). Operation of the SATCOM requires the Inertial Reference System (IRS) to be powered-on and aligned. It takes ten minutes for the IRS to become aligned from power on. Voice communication is available. The flight crew can receive or initiate a call in the cockpit. A single stroke chime accompanied by a flashing TEL light on the ACP indicates an incoming call to the airplane. The flight crew acknowledges the call by pushing the MIC/TEL switch on the ACP. The flight crew initiates a call by entering a phone number on the MCDU prior to pushing the MIC/TEL switch. Aircraft Communications Addressing and Reporting System (ACARS) The Aircraft Communications Addressing And Reporting System (ACARS) provides two-way data communications. Aircraft flight operations and maintenance data is collected automatically from systems and sensors, or is entered manually into the ACARS Management Unit (MU) through the MCDU, for downlink. The crew may also enter free text messages, weather report requests, and position reports. Data that can be uplinked and downlinked includes all of the following: Flight plan (Downlinked). Load. Wind (Downlinked). Position report data/requests. Weather reports. Free text messages. Emergency messages. Airlines application. MD-11 - Communications Page 5
An ACARS Management Unit (MU) is installed in the avionics rack and does the following: Receives the ground-to-air messages. Controls transmission of the air-to-ground messages. Collects data from various airplane systems. Converts digital data in receive and transmit modes. The MU receives data from: MCDUs. FMCs. Digital Flight Data Acquisition Unit (DFDAU) or Data Management Unit (DMU). CFDS. VHF3 system. Door sensors. Parking brake. Air/ground switch. SATCOM. Ground and satellite networks are responsible for transporting messages between the aircraft and the airline host computer, and are operated by different providers, depending on location. VHF3 radio or SATCOM communication is available as follows: The MU automatically locks in either VHF3 or SATCOM, as appropriate. VHF3 or SATCOM can be manually selected through the ACARS screen on the MCDU. SATCOM communication is possible when the airplane is within range of satellite coverage and SATCOM transmission is enabled. VHF communication is possible when the airplane is within range of a network ground station and VHF transmission is enabled. Typical VHF range is approximately 200 NM at 30,000 feet. During VHF communication, the radio transceiver is tuned to a frequency entered on the MCDU or by a ground station uplink frequency command. Voice mode or data mode VHF transmission is selected through the MCDU or the ground station. When in voice mode, the appropriate alert is displayed. The MU starts contact by transmitting when the flight crew wants to transmit, or when a predefined event occurs. The MU only transmits when the selected channel is available. If the transmission is not received (by the ground station), ACARS attempts to transmit again. After 6 attempts, if the message is not received, the flight crew receives an ACARS NO-COMM alert. The same process occurs for uplink messages. MD-11 - Communications Page 6
Comm.20 Service Interphone Communications-Components Jack Location FUEL SCHEDULING PANEL MAIN WHEEL WELL COMPARTMENT CENTER ACCESSORY COMPARTMENT ENGINE NUMBER 3 EXTERNAL GROUND POWER PANEL VERTICAL STABILIZER HORIZONTAL STABILIZER SCREW JACK AFT CARGO COMPARTMENT APU SERVICE PANEL TAIL CONE ENGINE NUMBER 2 SERVICE PANEL REAR AFT FUSELAGE COMPARTMENT CENTER CARGO COMPARTMENT AVIONICS COMPARTMENT AIR CONDITIONING COMPARTMENTS FWD CARGO COMPARTMENT ENGINE NUMBER 1 FUEL SCHEDULING PANEL DB1-2-1711 MD-11 - Communications Page 7
Comm.30 Communication Communications-Controls Radio Paneland Displays 1 2 3 ACTIVE VHF STBY VHF 4 VHF-1 VHF-2 VHF-3 HF-1 HF-2 5 AFT PEDESTAL, 2 ON LEFT 1 ON RIGHT DB1-2-1701 1. ACTIVE Window Displays the active frequency and selected radio. Displays ACARS in one of the windows for VHF-3. Displays FAIL in both windows in case of CRP failure. 2. Transfer Button Push to transfer the STBY frequency to the ACTIVE window for transmission. STBY frequencies cannot be transmitted until transferred to ACTIVE window. 3. STBY Window Displays the standby frequency and selected radio. 4. Frequency Selector Turn knobs to select frequency in STBY window only. 5. Radio Selector Switches (5) - white Push to select respective radio. Switch illuminates white. Selected radio is displayed in the STBY/ACTIVE windows. MD-11 - Communications Page 8
Audio Control Panel 1 2 3 MIC MIC MIC MIC MIC MIC MIC CALL CALL CALL CALL CALL TEL MECH VHF 1 VHF 2 VHF 3 HF 1 HF 2 SAT INT 4 10 9 8 CAB IDENT PA INT MIC ON CALL RADIO 1-VOR-2 1-ILS-2 1-ADF-2 MKR DME 5 1. Navigation Radio MIC/CALL Switches (5) - white MIC - Illuminates white when a navigation radio system MIC/CALL switch is pushed. Radio transmission is enabled for that system. CALL - If flashing, a call is being received on the radio system indicated below the flashing light. 2. MIC/TEL Switch - white MIC - Illuminates white, with SATCOM installed and voice enabled, when pushed to transmit via SATCOM. TEL - Flashes blue and a tone sounds when an incoming/outgoing SATCOM transmission is initiated. With MIC pushed to transmit, air to ground transmission is connected, TEL illuminates steady blue. When transmission is disconnected, TEL extinguishes. Pushing either RADIO PTT switch enables transmission through either the boom microphone or the oxygen mask microphone. 3. MIC/MECH Switch - white AFT PEDESTAL AND OBSERVER'S STATION MIC - Illuminates white when pushed, enabling communication with outside maintenance personnel through the external flight interphone jacks. Interphone jacks are located at the external ground power receptacle and at the nose landing gear. 7 6 DB1-2-1702 MD-11 - Communications Page 9
MECH - Illuminates white and a tone sounds when maintenance personnel are calling from the external power panel. MECH extinguishes when the flight interphone system is keyed from the cockpit. The hand, boom, or oxygen mask microphones may be used. 4. Communication Receiver Volume Control Knobs (7) All volume control knobs on the ACP are illuminated and protrude out with a white band at the base when pushed on. The knobs are used to control the volume of the selected radio. 5. INT/RADIO Switch This switch provides the same function as the PTT switch on the control wheel. When pushed and held to INT, flight interphone transmission is possible even though a non-interphone MIC selector is illuminated. When the switch is held in RADIO and the approppriate radio MIC/CALL switch is pushed, radio transmission is possible with either the boom or oxygen mask microphone. The RADIO position overrides flight interphone actuation with the PTT switch on the control wheel. 6. Navigation Receiver Volume Control Knobs (7) The knobs control the audio of the NAV systems designated above or below the selected knob. For an operational description of the VOR 1/2, ILS 1/2, ADF 1/2, MKR, and DME systems refer to the Instrumentation and Navigation chapter. 7. PA Button System deactivated. 8. CAB Volume Control Knob Controls cabin/service interphone volume. 9. CAB MIC/CALL Switch - white Pushing this switch causes MIC to illuminate white and makes it possible to communicate on the service interphone. Transmission can be made with either the boom or oxygen mask microphone by pushing the hand mic PTT or radio PTT. If CALL illuminates white and a tone sounds, a call is being made from the cabin attendant panel indicated on the service interphone call panels. The volume control knob controls the cabin/service interphone volume at the audio panel. 10. IDENT Switch - white ON - Illuminates white when pushed. Enables voice and coded identification of DME, VOR, ADF, and ILS navigation receivers. MD-11 - Communications Page 10
Cockpit Jack Panel 1 2 BOOM MICROPHONE HEADSET 1. BOOM MICROPHONE Jack Allows connection of boom microphone to the flight interphone system. 2. Spare HEADSET Jack DB1-2-1703 Allows connection of a spare headset, which is normally used with the handheld microphone at the right observer station. MD-11 - Communications Page 11
Control Wheel Microphone and PTT Switches 1 2 RADIO PTT LIGHT CONTROL PANEL 1. Control Wheel Microphone Switch This 3-position switch keys the flight interphone system as follows: Forward (Momentary) - Interphone. Aft (Momentary) - Radio. Center - Off. 2. RADIO PTT Switch (2) LB1-3-0015A RADIO PTT - Push for radio transmission through the boom or oxygen mask microphone. MD-11 - Communications Page 12
Cockpit Speakers and Service Interphone CALL Panel - Freighter 1 2 3 4 VOL COURIER CALL CALL RESET MAINT INTPH ON MECH CALL 5 RIGHT AND LEFT OVERHEAD LINER 6 FORWARD OVERHEAD PANEL CAG(IGDS) 1. Captain s and First Officer s Speakers Monitors audio signals, as selected by the Captain or First Officer. 2. Speaker VOL Control Knob VOL - Rotation of the speaker VOL knob adjusts speaker volume (excluding warnings). Speaker volume is reduced when the associated microphone is keyed (except during warnings and while oxygen mask microphone is in use). 3. COURIER/CALL Switch - white/blue COURIER - Illuminates white when the COURIER/CALL switch is pushed. Illuminates the courier station light and enables the aft pedestal handset for communication with the courier station. CALL - Illuminates blue when a call is made from the courier station to the cockpit. COURIER illuminates white when the system is powered. LB1-3-0053 4. MAINT INTPH/ON Switch - white/amber MAINT INTPH - Illuminates white when the system is powered. Illumination is controlled by the OVHD PNL FLOOD knob on the forward overhead panel. ON - Illuminates amber when the MAINT INTPH/ON switch is pushed. Connects the maintenance interphone jacks to the service interphone system. MD-11 - Communications Page 13
The handset on the aft pedestal allows service interphone communication with the ground crew. Service interphone jacks are located in various locations throughout the airplane. 5. MECH/CALL Switch - white/blue Pushing this switch momentarily sounds the mechanic call horn on the airplane exterior. MECH - Illuminates white when the system is powered. CALL - Illuminates blue when the PILOT S CALL button on the ground service panel is pushed. The service interphone system allows communication from the cockpit to any airplane service interphone jack. The aft pedestal handset is used for communication. Communication with the ground crew through the handheld or boom microphone is made by pushing the audio control panel MIC/MECH switch, and activating either the Captain s or First Officer s control wheel PTT switch or the audio control panel INT switch. 6. CALL RESET Button CALL RESET - Push to extinguish the CALL light. MD-11 - Communications Page 14
Service Interphone Handset 1 2 3 CAG(IGDS) 1. Handset Receiver Returning the handset to the cradle deactivates the service interphone system. 2. Push-To-Talk (PTT) Handset Switch Pushing the bar-type switch on the handset enables communication through the service interphone system. 3. Handset Microphone AFT PEDESTAL Pushing the PTT handset switch enables service interphone system communication through the handset microphone. LB1-3-0054 MD-11 - Communications Page 15
Cockpit Voice Recorder Panel 1 2 3 TEST ERASE 5 COCKPIT VOICE RECORDER FORWARD OVERHEAD PANEL HEADSET 600 OHMS 4 CAG(IGDS) 1. Test Monitor Meter Indicates the recording level during a test. When the TEST button is pushed, the meter should read in the green band. 2. TEST Button TEST - Push to initiate a timed test signal, applied at preset intervals, for each channel. The complete test cycle lasts approximately 5 seconds and is accompanied by an aural tone heard through the headset. 3. ERASE Button ERASE - Push and hold for 2 seconds, when the airplane is on the ground and the parking brake is set, to erase previously recorded cockpit sounds. 4. HEADSET Jack When the headset is plugged in to this jack and the TEST button is pushed, an aural tone indicates that the system is operational. 5. Cockpit Monitor Microphone LB1-3-0055 All audible sounds in the cockpit are recorded through the cockpit monitor microphone. MD-11 - Communications Page 16
Comm.40 Communications-Alerts NOTE: The associated cue switch is shown in parenthesis (XXX) following the alert. Amber Boxed Alerts (Level 2) RADIO TRANSMIT (MISC) - Any of the five radios (3 VHF, 2 HF) is keyed for more than 60 seconds. This alert is optional. Cyan Alerts (Level 0) ACARS MESSAGE - ACARS has received a message. ACARS NO COMM - ACARS has no available communications link. VHF-3 VOICE - ACARS is in voice mode. MD-11 - Communications Page 17
Comm.50 VHF System Communications-Functional Block Diagram Schematic CAPTAIN JACK CAPTAIN'S CONTROL PANEL FIRST OFFICER'S CONTROL PANEL F/O JACK MANAGEMENT UNIT NO. 1 MANAGEMENT UNIT NO. 2 OBSERVER CONTROL PANEL OBSERVER JACK COMM. RADIO PANEL-1 VHF-1 VHF-1 ANTENNA TO AMU 1 & 2 COMM. RADIO PANEL-3 VHF-3 VHF-3 ANTENNA TO AMU 1 & 2 COMM. RADIO PANEL-2 VHF-2 VHF-2 ANTENNA DB1-2-1712 MD-11 - Communications Page 18
HF System Block Diagram CAPTAIN'S JACK CAPTAIN'S CONTROL PANEL FIRST OFFICER'S CONTROL PANEL FIRST OFFICER'S JACK MANAGEMENT UNIT NO. 1 MANAGEMENT UNIT NO. 2 OBSERVER CONTROL PANEL COMM. RADIO PANEL-1 FROM TRANSCEIVER HF-2 HF-1 TRANSCEIVER FROM TRANSCEIVER HF-2 ANTENNA COUPLER NO. 1 OBSERVER JACK COMM. RADIO PANEL-3 COMM. RADIO PANEL-2 M OU N T ANTENNA ADAPTER ANTENNA HF-2 TRANSCEIVER ANTENNA COUPLER NO. 2 TO AMU 1 & 2 DB1-2-1713 MD-11 - Communications Page 19
SELCAL System Block Diagram SELCAL CODE SELECT PANEL VHF-1 ANNUNCIATOR CONTROL UNIT (ACU-3) CAPTAIN ACP-1 FIRST OFFICER ACP-2 VHF-2 VHF-3 SELCAL DECODER OBSERVER ACP-3 HF-1 HF-2 PTT RESET CENTRAL AURAL WARNING UNIT (CAWU) SPEAKER CHIME MANAGEMENT UNIT-1 MANAGEMENT UNIT-2 DB1-2-1715 MD-11 - Communications Page 20
ACARS Block Diagram MCDU 1, 2, & 3 FMC 1 & 2 VHF-3 CFDIU ACARS MANAGEMENT UNIT (MU) SATCOM (if installed) DFDAU PRINTER (if installed) GROUND SENSE DOORS PARK BRAKE SENSE DB1-2-1716 MD-11 - Communications Page 21