ATA 23 Communications PDF

BOMBARDIER DHC 8-400 (PWC PW150) ATA 23 - COMMUNICATIONS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS PURPOSE The aircraft communication systems have different sub-systems to...

BOMBARDIER DHC 8-400 (PWC PW150) ATA 23 - COMMUNICATIONS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS PURPOSE The aircraft communication systems have different sub-systems to do these functions: • • • • • • • • Communications in the Very High Frequency (VHF) band Communications in the High Frequency (HF) band Selective Calling (SELCAL) Noise and Vibration Control Announcements To The Passengers By The Pilots Or Flight Attendants Audio Management Cockpit Voice Recording Radio Management GENERAL DESCRIPTION The communication system has these sub-systems: • • • • • • • • VHF Communication HF Communication Selective Calling (SELCAL) Passenger Address and Communication Interphone System (PACIS) Active Noise and Vibration Control System (ANVC) Audio Integration System (AIS) Cockpit Voice Recording (CVR) System Radio Management TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 2 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 3 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS ACTIVE NOISE AND VIBRATION CONTROL SYSTEM (ANVC) VHF COMMUNICATION SYSTEM The Active Noise and Vibration Control System reduces the level of the periodic noise in the passenger cabin created by the aircraft propellers. The Very High Frequency (VHF) communication system gives short range lineof-sight, Amplitude Modulated (AM), two way voice and data communication. It gives short range airborne to ground, ground to airborne, and airborne to airborne communications. The system works by producing a secondary vibration field in the cabin, which is out of phase with the primary field. The primary and secondary fields combine to produce lower noise and vibration levels. There are two VHF communication systems installed. A third unit is optional. AUDIO INTEGRATION SYSTEM (AIS) HF COMMUNICATIONS SYSTEM The Audio Integration System (AIS) controls these audio functions: The High Frequency (HF) Communication system gives long-range, two way single sideband (SSB), AM, voice and data communication. An optional single or dual HF system can possibly be installed. It is controlled by an HF control unit and the Audio and Radio Control Display Units (ARCDU). SELECTIVE CALLING (SELCAL) The selective Calling (SELCAL) system interfaces with the VHF and HF radios to give visual and aural indications of ground station calls addressed to a specified aircraft. • • • Radio communication receivers and transceivers audio Radio navigation receivers audio Interphone communications between pilot, copilot, observer, and ground crew members COCKPIT VOICE RECORDING (CVR) SYSTEM The solid state Cockpit Voice Recorder (SSCVR) system records the last two hours of flight compartment audio and clock data. It records audio in a digital format in crash-survivable Non-Volatile Memory (NVM). PASSENGER ADDRESS AND COMMUNICATION INTERPHONE SYSTEM (PACIS) RADIO MANAGEMENT The Passenger Address and Communication Interphone System (PACIS) gives these functions: Two Audio and Radio Control Display Units (ARCDU) are used to control and show the status of the Radio Communication (RCOM) and Radio Navigation (RNAV) systems. Optional Flight Management System (FMS) control and display units can also control the RCOM and RNAV systems. • • • Passenger Address (PA) announcements to the passengers Interphone communications between the flight attendants and pilots for private conversations Flight attendant calls from switches in the Passenger Service Units (PSU) and lavatory TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 4 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - SPEECH COMMUNICATION SYSTEM BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 5 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS SPEECH COMMUNICATION PURPOSE The speech communication system gives the pilots ground to ground, airborne to ground, and airborne to airborne communications. GENERAL DESCRIPTION The speech communication system has these sub-systems: • • VHF Communication HF Communication VHF COMMUNICATION SYSTEM The Very High Frequency (VHF) communication system gives short range, line-ofsight, Amplitude Modulated (AM), two way voice and data communication. There are two VHF communication systems installed. A third unit is optional. Each system operates in the 118 to 135.975 Megahertz (MHz) frequency spectrum in 25 Kilohertz (kHz) channel spacing. HF COMMUNICATIONS SYSTEM The High Frequency (HF) Communication system gives long-range, two way single sideband (SSB), AM, voice and data communication. An optional single or dual HF system may be installed. The HF communication system transmits and receives high frequency communication signals in the 2.0 to 29.9999 MHz frequency radio spectrum with 100 Hz channel spacing. It is controlled by a control unit and the Audio and Radio Control Display Units (ARCDU). The HF control unit and the ARCDU control the HF audio and transmitter selection. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 6 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - SPEECH COMMUNICATION SYSTEM BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 7 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS The VHF communication systems are controlled by units that follow: • • • VHF COMMUNICATION PURPOSE Standby control unit, VHF 1 Audio and Radio Control Display Units (ARCDU) Flight Management System (FMS) Multi-Functional Control Display Units (FMS1, FMS2) The Very High Frequency (VHF) communication system gives short range line-ofsight Amplitude Modulated (AM), two way voice and data communication. The ARCDUs manually tune the VHF communication system frequencies and set the mode of operation. The FMS is used when the ARCDU malfunctions. GENERAL DESCRIPTION When energized, the standby control unit only tunes VHF transceiver No.1. The standby control unit is usually used when the two ARCDUs and FMS malfunction. The VHF communication system has these units: • • • The audio from the VHF communication transceivers is supplied to the Remote Control Audio Unit (RCAU) for audio integration. The ARCDUs and observer audio control panel control the RCAU to select the audio and change its level to the flight compartment speakers and pilot, copilot, and observer jack boxes. Transceiver Unit, Standby Control Antenna Two or three VHF communication systems operate independently in the 118.000 to 135.975 Megahertz (MHz) frequency spectrum with 25 Kilohertz (kHz) frequency spacing to give short range ground to ground, ground to airborne, and airborne to airborne communications. To make a VHF communication transceiver transmit, a Push To Talk (PTT) selection and microphone audio is needed. These signals are supplied through the RCAU to the VHF communication transceivers. The signal is Amplitude Modulated (AM). On aircraft with the Very High Frequency (VHF) communication system 8.33 kHz frequency spacing (CR823CH00185): The Aircraft Configuration Modules (ACM1, ACM2) are programmed to make the VHF communication system operate with 8.33 kHz frequency spacing. This narrow-band voice mode gives more channels to decrease the VHF radio frequency congestion in Europe. NOTE: The ACM can also be programmed to make the VHF communication system operate in the extended frequency range, 118.000 to 155.975 kHz. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 8 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - VHF 1 COMMUNICATION SYSTEM BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 9 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS VHF COMMUNICATION SYSTEM DETAILED DESCRIPTION The VHF 2 communications system operates like the VHF 1 communication system but it cannot be tuned by the VHF 1 standby controller. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 10 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - VHF 2 COMMUNICATION SYSTEM BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 11 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS VHF COMMUNICATION SYSTEM DETAILED DESCRIPTION CONTINUED On aircraft with the No.3 VHF COM installed (CR823CH00185): The No.3 VHF COM system is usually used with the ACARS. It operates like the VHF1 and VHF2 communication systems but it cannot be tuned by the VHF1 standby controller or FMS. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 12 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - VHF3 COMMUNICATION SYSTEM BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 13 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS INITIATED TEST VHF COMMUNICATION SYSTEM The TEST push button switch on the transceiver front panel is pushed to test the unit. The VHF transceivers are controlled by the two Audio and Radio Control Display Units (ARCDU 1, ARCDU 2). They control these operations: DETAILED DESCRIPTION CONTINUED • • TRANSCEIVER • • The VHF transceiver operates in these modes: • • • Tunes the VHF communication system and controls their operational modes Shows all data that is related to the operation of the VHF communication systems Monitors the operation of the VHF communication system to show malfunctions Controls the operation of the Audio Integration System (AIS) Power-On Self Test (POST) Operational Initiated Test POWER-ON SELF TEST (POST) The Power-On Self Test (POST) mode automatically starts after power-up. During the POST the VHF transceivers do these self-tests: • • • • • • • Hardware ARINC 429 Inputs Discrete Inputs Voltage Standing Wave Ratio (VSWR) Transmitter Receiver Indication of test in progress and successful completion OPERATIONAL MODE The operational mode has these modes: • • • Mode 0A Mode 0B Mode 1A TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 14 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - VHF TRANSCEIVER LOCATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 15 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS The HIRF module filters stray radiation from adjacent cabling and protects the unit from the indirect effects of lightning. Two boards connecting the rear connector and the receiver, management and power supply modules provide the protection and have filters, series resistors, capacitors and zenner diodes. VHF COMMUNICATION SYSTEM DETAILED DESCRIPTION CONTINUED The front panel has these features: TRANSCEIVER CONTINUED The two VHF transceivers are located on the upper shelf of the avionics rack at station points -25.45 and -36.5 kHz. The mounting tray protects and holds the wired assembly in place and helps dissipate heat. The VHF transceiver weighs 6.12 lb/2.77 kg. It has subassemblies mechanically packaged into a 8.08 in./205.2 mm high, 3.93 in./99.8 mm wide by 16.1 in./408.9 mm long case. A single recessed rack mounted rear panel connector and an RF connector interconnect the aircraft wire harness and antenna installation. The VHF transceiver is a conventional super heterodyne, AM double-sideband transceiver that operates between 118.000 and 135.975 MHz with 25 kHz channel spacing. The transceiver can be programmed to give 8.33 kHz channel spacing and operate to 156.975. The narrow-band voice mode has more channels to decrease the VHF frequency congestion in the upper airspace of Europe. Its transmit power is limited to 20 W. • • • • • Attachment lugs Handle TEST pushbutton switch Light Emitting Diodes (LED) Identification labels The LED on the transceiver front panel come on to indicate these conditions: • • • • • • PASS, operator initiated test did not sense a malfunction FAIL LRU, operator initiated test sensed a malfunction FAIL IN, an input fault on the ARINC 429 bus including incorrect data is sensed VSWR, VSWR is more than 2:1 TX, transmit mode RX, receive mode For easy access, the sides of the unit are hinged. The unit can also operate with an ACARS Management Unit. The VHF transceiver has these components: • • • • • • • Receiver module, located on left side of LRU viewed from LRU front panel Transmitter module, located in centre LRU section Power supply module, located in centre LRU section Data processing unit, located on right side of LRU HIRF module, located in rear panel area Power storage module, located in front panel area Wired chassis, located in rear panel area TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 16 of 228 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 17 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS VHF COMMUNICATION SYSTEM STANDBY CONTROL UNIT The standby control panel is attached to the forward part of the centre pedestal area with four dzus fasteners. It is a 3.15 in./80.01 mm high, 2.55 in./64.7 mm wide by 6.18 in./156.9 mm long unit. Two recessed rack-mounted rear panel connector interconnect the aircraft wire harness. The standby control unit tunes VHF1 only. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 18 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - STANDBY CONTROL UNIT LOCATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 19 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS VHF COMMUNICATION SYSTEM ANTENNA The VHF1 antenna is attached to the upper fuselage with six mounting bolts at station point X.186 and the VHF2 antenna is attached to the lower fuselage with six mounting bolts at station point X.81. An aluminium foil gasket with an elastomeric sealant makes electrical contact between the gasket and aircraft structure. The pressure applied during installation gives a contouring feature to let the gasket contact the two mating surfaces. The antennas weigh 2.2 lbs/0.9307 kgs. The blade has a preformed radiating element in a thermoplastic assembly. A Radio Frequency (RF) N-type female connector is attached to the aluminium base. The antenna is a vertically-polarized antenna that operates in the VHF communications frequency spectrum of 118 to 156 MHz. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 20 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - VHF ANTENNA LOCATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 21 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS VHF COMMUNICATION SYSTEM CONTROLS AND INDICATIONS ARCDU The Audio and Radio Control Display Units (ARCDU 1, ARCDU 2) are used to set the VHF communication modes and to manually tune the VHF communication Receivers (VHF COM1, VHF COM2) frequencies. The Flight Management System (FMS) will also tune the communication receivers. The ARCDU selections control the VHF communication frequencies and the mode to be used as described in the following table: SELECTION DESCRIPTION OFF The ARCDU is not energized ON The ARCDU is energized and it controls and tunes its related radio system BOTH The ARCDU is energized and it controls and tunes its related and opposite radio systems FMS The FMS or ARCDU controls and tunes its related and opposite radio systems TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 22 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - ARCDU, VHF COMMUNICATION CONTROLS AND INDICATIONS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 23 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS The CH key is pushed again to change from the channel memory mode back to the frequency selection mode. The channel memory annunciator will go out of view. VHF COMMUNICATION SYSTEM NOTE: CONTROLS AND INDICATIONS The TUNE double rotary knobs selection can roll over. ARCDU CONTINUED The side key adjacent to the VHF communication display area is pushed to highlight the preset indication. It is pushed again to make the preset frequency active and the frequency that was active, the new preset frequency. When the side key adjacent to the VHF communication display area is pushed, the preset indication in the display area changes to reverse video to show the selection. The TUNE double rotary knobs located at the middle right part of the ARCDU are turned to change the preset indication. The side key adjacent to the VHF communication display area is pushed and then the CH key to set the channel memory mode for VHF communication. The VHF communication channel memory mode lets the preset frequency area show one of eight different programmed channels. If the preset frequency shown relates to a channel memory, a channel memory annunciation is shown on the second data line that relates to the channel number. The TUNE double rotary knobs are turned to change the preset frequency indication from eight programmed channels. The channel memory annunciation changes with the preset channel memory frequency indication. NOTE: If the preset frequency does not relate to a channel memory when the mode is set, no channel memory annunciation is shown. A TUNE double rotary knobs selection causes the display area to start with CH1 when turned clockwise or CH8 when turned counter-clockwise. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 24 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - ARCDU, VHF COMMUNICATION FREQUENCY CONTROL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 25 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS VHF COMMUNICATION SYSTEM CONTROLS AND INDICATIONS ARCDU CONTINUED The side key adjacent to the VHF communication display area is pushed and then the EXP key to show the VHF communication particular page. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 26 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - ARCDU, VHF COMMUNICATION PARTICULAR PAGE SELECTION TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 27 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS VHF COMMUNICATION SYSTEM CONTROLS AND INDICATIONS ARCDU CONTINUED The particular page is used to change the VHF communication Receiver (VHF COM1, VHF COM2) modes and functions that follow: • • Squelch Channel Programming SQUELCH The side key adjacent to the SQUELCH ON, OFF legend is pushed to manually set the squelch on or off. The automatic squelch circuit is disabled to let the transceiver noise be heard to make sure that the unit is energized. The white legend changes to reverse video to show the selection. When SQUELCH OFF is set, the VHF1 display area will also show a green SQL indication. The SQL indication goes out of view when SQUELCH ON is set or VHF1 is transmitting and a TX indication is shown. CHANNEL PROGRAMMING Eight preset channels are set on a different page for VHF communication tuning to show preset frequency selections for the radio system. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 28 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - ARCDU, VHF COMMUNICATION PARTICULAR PAGE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 29 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS VHF COMMUNICATION SYSTEM CONTROLS AND INDICATIONS ARCDU CONTINUED The side key adjacent to the CHANNELS legend is pushed to show the channel programming page. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 30 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - ARCDU, VHF COMMUNICATION CHANNELS SELECTION TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 31 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS VHF COMMUNICATION SYSTEM CONTROLS AND INDICATIONS ARCDU CONTINUED The channel programming page has these indications: • • • Index of all radios with channel programming Channel memory annunciators (CH1 through CH8) Programmed frequency values for the radio selection The two display areas at the top of the screen show the radios that can be channel programmed. The left display area shows the radios that are related to the pilot side and the right display area shows the radios that are related to the copilot side. One radio is always set and is shown in reverse video. NOTE: The radio for the related particular page is automatically set. The side key adjacent to display area is pushed to show the channel memory frequencies for a different radio. Four other display areas each show two channel memory annunciators with their channel memory frequency values that relate to the radio selection. NOTE: When the ARCDU is set to the ON position, only the related radios can be channel programmed. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 32 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - ARCDU, VHF COMMUNICATION CHANNELS PAGE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 33 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS VHF COMMUNICATION SYSTEM CONTROLS AND INDICATIONS ARCDU CONTINUED The side key adjacent to the channel memory display area is pushed to highlight the top memory frequency indication. It is pushed two times to highlight the bottom memory frequency indication. When the side key adjacent to the channel memory display area is pushed, the indication in the display area changes to reverse video to show the selection. The TUNE double rotary knobs located at the middle right part of the ARCDU are turned to change the preset indication. The new memory frequency is set by any condition that follows: • • • A side key is pushed Five seconds after a TUNE double rotary knobs selection The EXP or PG 1/2 key is pushed to show a different page TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 34 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - ARCDU, VHF COMMUNICATION CHANNEL MEMORY PROGRAMMING TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 35 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS ROTARY MICROPHONE (TRANSMITTER) SELECTION VHF COMMUNICATION SYSTEM SYSTEM VHF 1 VHF communications 1 CONTROLS AND INDICATIONS VHF 2 VHF communications 2 ARCDU CONTINUED AUX 1 VHF communications UHF communications The VHF1 or VHF 2 Potentiometer pushbutton switches control this audio data: • • • On Off Level The Communication receiver display area shows the volume level as a vertical bar graph. The height of the bar graph shows the volume selection level. When the audio is selected off, the bar graph is shown in white. The bar graph changes to green when the audio is selected on. The ARCDU have the radio and audio controls for the VHF transceivers that follows: Rotary microphone (transmitter) selector BOOM/MASK toggle switch NORM/EMER toggle switch The rotary microphone selector switch is set to a radio position followed by a Push to Talk (PTT) selection to make transmission. When the BOOM/MASK toggle switch is set to BOOM, the headset boom microphone supplies audio to VHF transceiver through the Remote Control Audio Unit (RCAU). When the BOOM/MASK toggle switch is set to MASK, the oxygen mask microphone supplies audio to the Audio and Radio Management System (ARMS). NORM/EMER TOGGLE SWITCH When the NORM/EMER (Normal/Emergency) toggle switch is set to the NORM position, it causes the RCAU to function in the normal operational mode. The audio outputs are independently controlled by the potentiometer pushbutton switches. The NORM/EMER (Normal/Emergency) toggle switch selection to the EMER position causes the RCAU to function in the emergency mode. Electrical power is removed from the related circuit card in the Remote Control Audio Unit (RCAU) to cause a relay to connect the headphone and speakers directly to the related VHF Communication transceiver. The audio is set to predetermined level and cannot be controlled by the potentiometer pushbutton switches. Also, the microphone key line is directly connected to the related VHF Communication transceiver. ROTARY MICROPHONE (TRANSMITTER) SELECTOR The rotary microphone selector switch is turned to make a radio transmitter selection that follows: TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY or BOOM/MASK TOGGLE SWITCH The top part of the potentiometer is pushed to turn the specific audio signal to the headphone on or off. The VHF1, or VHF2 pushbutton switch is pushed on the ARCDU to make its audio available to the flight crew member. When the SPKR pushbutton potentiometer switch is pushed, the VHF Communication audio is routed to the two flight compartment speakers. A loudspeaker graphic is shown in the INT window. • • • 3 If the VHF transceiver malfunctions, the Audio and Radio Control Display Units (ARCDU 1, ARCDU 2) show a FAIL legend in red characters below the active frequency. ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 36 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - ARCDU, VHF COMMUNICATION AUDIO CONTROL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 37 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS ACTIVE FREQUENCY INDICATION VHF COMMUNICATION SYSTEM The active frequency indication shows the active (ACT) frequency selection. A TX indication is shown when the VHF transceiver is transmitting. CONTROLS AND INDICATIONS STANDBY FREQUENCY INDICATION STANDBY CONTROL PANEL The standby frequency indication shows the frequency selection. A standby control panel is used to control the VHF1 frequency selections when the two ARCDU displays malfunction. ACTIVE/STANDBY TOGGLE SWITCH The stby controller has these controls and indications: The active/standby toggle switch is pushed and held for three seconds to toggle the active and standby frequencies. If the indication malfunctions, the switch can be pushed and held for seven seconds or more to tune the VHF transceiver to 121.500 MHz. • • • • • • ON/OFF/TEST Switch Frequency Selector Active/Standby Toggle Switch Active Frequency Indication Standby Frequency Indication Transmit Annunciation The ARCDU and the observer Audio Control Panel (ACP) interface with the RCAU to control this data: ON/OFF/TEST ROTARY SWITCH The ON/OFF/TEST switch is set to the ON position to energize the standby control panel and to control the VHF1 frequency selections. It is set to the TEST position to do a VHF COM1 squelch test mode. • • • • Push To Talk (PTT) Microphone audio Headphone audio Speaker audio NOTE: When the ON/OFF/TEST switch is set to the ON or TEST position, the two ARCDU VHF1 active frequency indications show a green STBY CTL message. FREQUENCY SELECTOR The two frequency rotary selectors are turned to change the standby frequency indication. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 38 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - VHF1 COMMUNICATION STANDBY CONTROLS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 39 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS VHF COMMUNICATION SYSTEM INTERFACES The aircraft left essential and right main buses supply 28V DC electrical power through 10 A circuit breakers to the VHF transceivers (VHF1, VHF2). The circuit breakers are located in position F1 on the left circuit breaker panel and D6 on the avionics circuit breaker panel. The aircraft left essential bus also supplies 28V DC electrical power through a 1 A circuit breaker to the standby control panel. The circuit breaker is located in position D9 on the avionics circuit breaker panel. The VHF communication system (VHF1, VHF2) has two VHF transceivers with related antennas. A single coaxial cable is routed to each VHF transceiver. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 40 of 228 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 41 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS VHF COMMUNICATION SYSTEM TESTS The VHF Transceiver front panel has a TEST pushbutton switch to start a Power-On Self Test (POST) and six Light Emitting Diodes (LED) to show the unit condition. The FAIL LRU, FAIL IN, or PASS indications come on with the test. The front panel shows an indication for these conditions: LED COLOUR CAUSE FAIL LRU Red Internal malfunction FAIL IN Red ARINC 429 or discrete input malfunction PASS Green VSWR Red TX Green Transmit mode RX Green Receive mode No malfunction sensed Voltage Standing Wave Ratio (VSWR) is more than 2:1 The green PASS indication comes on to show a good test result. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 42 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - VHF TRANSCEIVER, TEST TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 43 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS capacitor, and HF power amplifier coupler, by the receiver/exciter. HF COMMUNICATION The audio is removed from the Radio Frequency (RF) and is supplied through the Remote Control Audio Unit (RCAU). The ARCDUs and observer audio control panel control the Remote Control Audio Unit (RCAU) to change the audio level to the flight compartment speakers and pilot, copilot, and observer jack boxes. PURPOSE The High Frequency (HF) Communication system gives long-range, two way single sideband (SSB) or AM, voice and data communication. GENERAL DESCRIPTION The RCAU is controlled by the ARCDUs and observer audio control panel control. The HF Communication system has these units: • • • • • • • A Push To Talk (PTT) selection, makes the HF receiver/exciter transmit, and microphone audio is supplied through the RCAU to the receiver/ exciter. The audio is modulated in the receiver/exciter and supplied through the HF power amplifier coupler, and antenna capacitor to the HF antenna. NOTE: Control Unit Receiver/Exciter Mounting-Receiver/Exciter Tray HF Power Amplifier Coupler Mounting-Coupler Tray HF Antenna Capacitor Bridging Amplifier (dual system only) The HF antenna is part of the vertical stabilizer leading edge. The antenna transmits a very high RF current that can be 50 A. The HF communication system transmits and receives high frequency communication signals in the 2.0 to 29.9999 MHz frequency radio spectrum with 100 Hz channel spacing to give long range airborne to ground, ground to airborne, and airborne to airborne communications. The HF communication system is controlled by units that follow: • • HF Control Unit Audio and Radio Control Display Units (ARCDU) The HF control unit manually tunes the HF communication system frequencies, sets the mode of operation, and stores preset channel frequencies. The audio control is set to the maximum level when the HF system is set to on. In the receive mode, radio signals are received, through the HF antenna, antenna TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 44 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - HF COMMUNICATION SYSTEM BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 45 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS HF COMMUNICATION GENERAL DESCRIPTION The dual HF system has one HF antenna with a dual capacitor, two HF power amplifier couplers with bridging amplifiers, two receiver exciters, and two HF control units. Each HF control unit manually tunes its related HF communication system frequencies, sets the mode of operation, and stores preset channel frequencies. When two HF systems use one antenna, the two systems can receive at the same time, but only one system can transmit at one time. The first system with a PTT is set to transmit, and the other system is prevented from transmitting. The single antenna in a dual system can be tuned only to one frequency at one time. If the two systems are tuned to different frequencies, the stronger reception is sensed on the system that was last used for transmission. A dual system needs bridging amplifiers and a dual antenna capacitor. The dual antenna capacitor connects the antenna to the active power amplifier coupler. The bridging amplifiers divide and supply the received signal from the active power amplifier coupler to the two receiver/exciters. The audio is removed from the Radio Frequency (RF) and is supplied through the Remote Control Audio Unit (RCAU) to the headphones and speakers. The ARCDUs and observer audio control panel control the Remote Control Audio Unit (RCAU) to also change the audio level to the flight compartment speakers and pilot, copilot, and observer jack boxes. A pilot or copilot Push To Talk (PTT) selection, makes the related microphone audio in the RCAU go to the set receiver/exciter. The audio is modulated in the receiver/ exciter and supplied through the related HF power amplifier coupler, and dual antenna capacitor to the HF antenna. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 46 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - DUAL HF COMMUNICATION SYSTEM BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 47 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS HF COMMUNICATION DETAILED DESCRIPTION High frequency single side band communications gives long range transmission and reception over distances of thousands of miles. It uses skywave propagation that reflects the HF radio waves directed towards outer space back to the earth surface by the ionosphere. The HF communication system transmits a single sideband (SSB) or AM radio signal. In SSB, all of the transmitter power output is intelligence. Solar disturbances can cause propagation of HF radio waves to deteriorate. Atmospheric conditions like precipitation and thunderstorms can also cause the HF signals to deteriorate. The result is reduced receive audio quality. The HF communications system operates in Amplitude Modulation (AM) or Upper Sideband (USB) modes. The Lower Sideband (LSB) operating option is not approved for airborne HF operation. The HF Communication system operates in the modes that follow: • • • Amplitude Modulation Equivalent (AME) Single Sideband (SSB) A3A TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 48 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS SIMPLEX OPERATION HF COMMUNICATION DETAILED DESCRIPTION The simplex operation uses the same frequency for transmission and reception. Each can be set to operate in simplex AM or USB mode. It is usually used for communication with ATC and ARINC. In this mode, one person can only transmit while the other can only receive. AMPLITUDE MODULATION EQUIVALENT (AME) OPERATION SEMI-DUPLEX OPERATION The selected frequency and two sidebands are transmitted. Approximately 2/3 of the transmitted power is used to transmit the carrier frequency which contains none of the voice frequencies. The sidebands have voice frequencies. The semi-duplex operation uses different frequencies for transmission and reception. In this mode, one person can only transmit while the other can only receive. Semiduplex operation is usually used by the maritime radiotelephone network such as public correspondence stations. SINGLE SIDEBAND (SSB) OPERATION RECEIVE ONLY OPERATION Before transmission, the receiver/exciter electronically removes the carrier wave and one sideband. The remaining single sideband is transmitted. When the receiver/exciter receives a SSB signal, the required carrier frequency is combined with the received upper sideband (USB) signal and then demodulated to get the required audio. Channels can be programmed for receive only operations by not programming a transmit frequency for the selected channel. Receive-only operations are used where transmission on the assigned frequency is not approved such as weather information stations. A3A (USB REDUCED CARRIER TELEPHONE MODE) OPERATION INTERFACES This public correspondence mode is seldom used and is annunciated by the display of both AM and USB at the same time. The mode is usually not necessary for ITU channel communication but older base stations may require its use. The aircraft left main bus supplies 28V DC electrical power through a 25 ampere and 5 ampere circuit breakers to the HF receiver/exciter and control unit. The circuit breakers are located in position N2 and M2 on the avionics circuit breaker panel. When selected, a small amount of carrier frequency is transmitted and used by the ground station to activate the ringer and lock the receiver to the transmit frequency. The different HF frequency selections automatically cause one of the sub-modes of operation that follows: • • • Simplex Semi duplex Receive only TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 49 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS HF COMMUNICATION CONTROL UNIT The control unit is installed with four dzus fasteners in the aft centre pedestal area of the flight compartment, aft of the ARCDU. The control unit weighs 1.1 lb/0.499 kg. It has subassemblies mechanically packaged into a 2.00 in./50.8 mm high, 5.0 in./127 mm wide by 7.7 in./195.6 mm long case. The HF control unit is used to set the frequency and mode of operation of the system. The unit shows this information to the flight crew. The power supply used to power the Receiver/Exciter is a high efficiency switching supply which provides regulation by using current and voltage-sensing feedback to control the duty-cycle of the switching transistor. The operating voltages for the control unit are supplied from the receiver/exciter and are +192, +12, +5, and -26V DC. A single HF installation has one control unit and a dual HF installation has two. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 50 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - CONTROL UNIT LOCATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 51 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS All channels can be set to operate as semi-duplex, simplex, or receive-only. HF COMMUNICATION The receiver/exciter is powered by 28V DC. Current limiting and a power-on reset feature are implemented. The switching power supply supplies +192V DC for display, +12, +5, -26V DC to the control unit. RECEIVER/EXCITER The Receiver/Exciter is attached to a shock-mounted tray under the floor, on a shelf located between station points X216.00 and X236.00. The unit is installed with free air space surrounding the top and rear of the unit for convectional cooling. It weighs 7.0 lb/3.17 kg. It has subassemblies mechanically packaged into a 5.25 in./133.3 mm high, 3.0 in./76.2 mm wide by 11.94 in./303.7 mm long case. The Receiver/Exciter has receiver and low-level transmitter circuits. Frequencies are controlled by a temperature-compensated crystal oscillator which supplies an immediate frequency reference. Fault indication is given in the HF system for problems related to tuning failure to achieve impedance matching between the antenna and PA/Coupler output during initial tuning attempts or subsequent to a tuned condition and after VSWR degradation. The malfunction condition is shown on the controller display wherein all digits will flash. An attempt to clear the condition may be made by a second tuning attempt keying microphone line but subsequent failures to load indicate equipment malfunction. Additional causes for failure indication can be due to a generated fault signal within the antenna coupler which is input to the microprocessor when excessive amplifier temperature is detected or during bias regulator malfunction. Bias regulation is achieved through temperature monitoring and monitoring of average output power in order that bias voltages may be lowered during high duty-cycle power waveforms such as is required for AM transmissions. The Receiver/Exciter has these five modes: • • • • • AM Receive AM Transmit SSB Receive SSB Transmit Tune During normal operation, the channel number, receive and transmit frequencies and emission mode are recorded in the internal Random Access Memory (RAM) of the microprocessor. This gives rapid access for frequency changes and synthesizer calculations. The channel number, emission mode and frequency mode frequency are also recorded in the EEPROM for non-volatile storage when the system power is off. These data are recorded during initiation of a transmit/tune sequence. The control unit has 99 programmable channels and 280,000 selected frequencies. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 52 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - RECEIVER/EXCITER LOCATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 53 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS With single tone modulation Carrier Wave (CW) the Average Power detector limits the output power to approximately 38 W. With multiple simultaneous modulating tones such as voice or data where average power is less than 38 W, the Peak Power detector monitors the output power levels and limits maximum power to 150 W. HF COMMUNICATION MOUNTING-RECEIVER/EXCITER TRAY The mounting tray is attached to four shock mounts, and to the aircraft structure with grounding straps. Solid conductive metal straps, typically one inch thick, are used for RF bonding. The grounding straps are kept as short as possible and attached so that operation of the shock mounts are not interfered with. HF POWER AMPLIFIER COUPLER The power amplifier coupler is vertically installed adjacent to the HF antenna in the left side of the vertical stabilizer approximately at location X920.00. The amplified signal is then sent to the coupler section where it is matched to the antenna impedance 50. The coupler is capable of matching with less than 2:1 VSWR the 50 power amplifier output to the antenna impedance. The matching network includes an inductor/capacitor network which either matches the antenna to 50 or supplies 12.5 plus an additional inductance of a transformer to increase the impedance to 50. The control circuit for the matching network is a microprocessor which is programmed to operate relays within the network such that the optimal configuration of the inductor and the capacitor is selected depending on the measured antenna impedance. To get maximum efficiency, proper RF bonding of the PA/Coupler to the airframe is made as follows: • • • • The PA/Coupler mounting tray is bonded to the mounting surface or shelf with two ground straps The ground stud on the PA/Coupler is directly bonded to the mounting surface or shelf with a ground strap The ground stud on the PA/Coupler is bonded directly to the skin or the airframe structure with a ground strap The PA/Coupler is bonded to the skin of the aircraft through the shield of the antenna feed coax The power amplifier coupler weighs 12.5 lb/5.67 kg. It has subassemblies mechanically packaged into a 7.24 in./138.9 mm high, 7.24 in./138.9 mm wide by 14 in./355.6 mm long case. The Power Amplifier Coupler unit amplifies the signal from the receiver/exciter unit. Two different power detectors are used. One is a Average Power detector which is set to approximately 38 Wand the other is a Peak Power detector set to 150 W Peak Envelope Power (PEP). TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 54 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - HF POWER AMPLIFIER COUPLER LOCATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 55 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS HF COMMUNICATION MOUNTING-COUPLER TRAY The PA/Coupler is attached to a mounting tray. Four shock mounts and two tray ground straps connect the unit and the mounting tray. The airframe to unit ground strap is attached to a ground stud and extends to an area on the airframe located near the antenna feed through unit. HF ANTENNA CAPACITOR The capacitor has a porcelain feed through termination and is attached to the vertical stabilizer in series with the output of the PA/Coupler. It is 3.656 in./92.862 mm long by 3.656 in./92.862 mm wide by 4.081 in./103.657 mm high. The capacitor lets the antenna coupler efficiently tune short grounded antennas. The shunt antenna is an electrically isolated section of the leading edge of the vertical stabilizer. An external capacitor isolates the high current. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 56 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - HF ANTENNA CAPACITOR LOCATOR (DUAL) TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 57 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS HF COMMUNICATION BRIDGING AMPLIFIER Two bridging amplifiers are required for dual installation and each are installed directly onto the front of the respective PA/coupler. The bridging amplifier is component that lets both receivers operate from one antenna in a dual system installation. It divides and routes the receive signal from the active antenna coupler to the two receiver/exciters. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 58 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - HF BRIDGING AMPLIFIER LOCATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 59 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS CLARIFIER HF COMMUNICATION CONTROLS AND INDICATIONS The CLARIFIER control supplies up to 250 Hz of local oscillator adjustment during the receive operation only. The function is used during USB operation and adjusts the master reference oscillator frequency, to correct the received speech deterioration due to drift or inaccuracy of the reinserted carrier frequency. HF CONTROL UNIT MODE The HF control unit has these control functions: This control is used to set the emission mode (AM and USB). The switch is active at all times except during transmission. A3A is indicated by displaying AM and USB messages at the same time beneath the HF frequency display. • • • • • • • • Off/Volume Control Squelch Control Clarifier Control Mode Selection Frequency/Channel Transfer Channel and Frequency Control Knobs Programme Selection Store Selection FREQ/CHAN Transfers the HF system from a direct frequency operation to a channel form of operation. During channel operation, the channel number, emission mode and active frequency are shown. When transmitting in the channel mode, the transmit frequency and an added TX message are shown. OFF/VOLUME CONTROL The OFF/VOLUME control turns the system off and on and controls the volume with ARCDU. A clockwise rotation past the first click turns the system on. Further rotation increases audio level. It takes about two minutes for the unit to warm up. Until then, no frequencies are shown on the display. The last frequency used is shown if the FREQ/ CHAN pushbutton switch is out. The last active channel used is shown if the FREQ/ CHAN button switch is in. All preset channels are stored in non-volatile memory and can be used when the system comes on. The HF control unit volume is set at its maximum level and the ARCDU is used to control the audio level. ARCDU does not show an HF volume level. CHANNEL/FREQUENCY SELECT Two concentric dials act as increment decrement switches. CHANNEL CONTROL SQUELCH The SQUELCH control supplies a variable squelch threshold control, to help eliminate nuisance background noise. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY During direct frequency mode, the desired frequency is set with a cursor/digit increment-decrement switch. The HF system operates in simplex mode. Transmission on any 100 kHz frequency is available in the frequency range of 2-30 MHz. A TX message is shown along with the emission mode. The inner concentric knob varies the channels from 1 to 99 when the FREQ/CHAN switch is in CHAN position (in). The outer knob is not functional in this mode. ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 60 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - HF COMMUNICATION CONTROL UNIT SELECTIONS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 61 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS The control unit uses a high voltage gas discharge display that shows all frequencies and preset channel numbers. Smaller gas discharge characters TX, PGM, LSB, AM, USB show the emission mode, the transmit indicator and the program mode indication. HF COMMUNICATION A photocell on the face of the control unit automatically adjusts the control unit display lighting intensity according to the cockpit ambient light level. CONTROLS AND INDICATIONS HF CONTROL UNIT CONTINUED FREQUENCY CONTROL With the FREQ/CHAN knob in the FREQ position out, the outer concentric knob changes the cursor position one step to the digit that the pilot desires to change. The inner knob changes the frequency in increments or decrements of 1 MHz steps from 2 to 29 MHz. PROGRAMME (PGM) This control allows channel frequencies to be modified. In the programme mode, the channel number, emission mode and transmit frequency are shown on the control unit display. Transmission is inhibited, but the transmission frequency may be viewed when the microphone key is pushed. STORE (STO) The STO pushbutton switch has these functions: • • • • Supplies the transmit frequency of a duplex channel. The STO button is pushed to show TX and the transmit frequency on the control head. The receiver monitors the transmit frequency When the STO button and microphone key are pushed, a 1000 Hz tone is transmitted to break the squelch at some ground stations When in the programme mode, the STO button is pushed to enter the selected frequency into the channel to be programmed The STO button is pushed to clear error conditions errors are annunciated by a flashing E displayed for more than 3 seconds TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 62 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - HF COMMUNICATION CONTROL UNIT SELECTIONS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 63 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS BOOM/MASK Toggle Switch: When the BOOM/MASK toggle switch is set to BOOM, the headset boom microphone supplies audio to the HF transceiver through the Remote Control Audio Unit (RCAU). HF COMMUNICATION When the BOOM/MASK toggle switch is set to MASK, the oxygen mask microphone supplies audio to the RCAU. The ARCDU and the observer Audio Control Panel (ACP) interface with the RCAU to control this data (refer to 23-51-00): CONTROLS AND INDICATIONS ARCDU The ARCDU have the radio and audio controls for these HF transceivers: • • • Potentiometer pushbutton switches Rotary microphone (transmitter) selector BOOM/MASK toggle switch • • • • Push To Talk (PTT) Microphone audio Headphone audio Speaker audio All HF audio input/output is sent to the Remote Control Audio Unit (RCAU) for flight compartment distribution. POTENTIOMETER PUSHBUTTON SWITCHES The HF potentiometer pushbutton switches control this audio data: • • • On Off Level The top part of the potentiometer is pushed to turn the specific audio signal to the headphone on or off. The HF pushbutton switch is pushed on the ARCDU to make its audio available to the flight crew member. When the SPKR pushbutton potentiometer switch is pushed, the HF communication audio is routed to the two flight compartment speakers. A loudspeaker graphic is shown in the INT window. ROTARY MICROPHONE (TRANSMITTER) SELECTOR The rotary microphone selector switch is turned to the HF position to make a HF radio transmitter selection. The rotary microphone selector switch is set to a radio position followed by a Push to Talk (PTT) selection to make transmission. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 64 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - ARCDU, HF COMMUNICATION CONTROLS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 65 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS The Selective Calling (SELCAL) System has these units: • • SELECTIVE CALLING (SELCAL) PURPOSE SELCAL Decoder Code Selector Box The Selective Calling (SELCAL) System connects with these units: The selective calling (SELCAL) system tells the pilots of an incoming call on one of the VHF or HF radios. GENERAL DESCRIPTION • • • • • VHF Communication Transceivers (VHF1, VHF2, VHF3) HF Communication Transceivers (HF1, HF2) Remote Control Audio Unit (RCAU) Audio and Radio Control Display Units (ARCDU1, ARCDU2) Flight Data Processing System (FDPS1, FDPS2) The SELCAL system monitors encoded calls from a ground station radio transmission through a VHF or HF communication receiver. A special code four audio tones that relates to the aircraft is. NOTE: A SELCAL code selector sets the special aircraft code and supplies it to the SELCAL decoder. When an incoming call is received, the receiver supplies the four audio tones to the SELCAL decoder. The SELCAL decoder checks the special code with the set aircraft code. If the codes match, the SELCAL decoder supplies a signal to the Audio and Radio Control Display Units (ARCDU1, ARCDU2) to make them show an indication for the radio that received the call. It also sends a signal to the Warning Tone Generators (WTG1, WTG2) in the Flight Data Processing System (FDPS1, FDPS2) to sound a 1200 Hz tone for 3 seconds through the Remote Control Audio Unit (RCAU), flight compartment speakers, and pilot, copilot, and observer jack boxes. The SELCAL decoder is reset by a Push To Talk (PTT) selection of the related communication transceiver. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 66 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - SELCAL BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 67 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS SELECTIVE CALLING (SELCAL) DETAILED DESCRIPTION The squelch operation of a VHF communication transceiver that receives a strong signal is usually good but the HF signal reception can fade. Sometimes, it may be necessary to deliberately disable the squelch control to make sure that the audio is heard with the unwanted background noise. To stop such radio noise during flight, the SELCAL system lets the pilots set the volume level of the related radio to low or off. The SELCAL system is also used by the airline operations department to call the aircraft. The SELCAL code selector box is used to set a special four letter code to identify the aircraft registration. Audio tones from incoming calls are received by a radio and detected, amplified and routed to the SELCAL decoder. If a match between the incoming call and aircraft code is sensed, the SELCAL decoder sends a discrete signal through the Remote Control Audio Unit (RCAU) to the two ARCDU. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 68 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - SELCAL CODE SELECTOR BOX TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 69 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS SELECTIVE CALLING (SELCAL) CONTROLS AND INDICATIONS ARCDC When a SELCAL incoming call is sensed a magenta SELCAL message flashes at a 1 Hz rate in the interphone display area of each ARCDU. The message has CALL label with a label for the related radio. For example a CALL HF 1 message. If several calls on different radios are received at the same time, the indication will stop flashing and an indication for each radio is shown sequentially every second. The indication will continue to flash when there is only one incoming call. Also, a 3 second, 1200 Hz warning tone sounds in the flight compartment speakers and the pilots headsets for each incoming call. A Push To Talk (PTT) selection of the related radio caused the indication to reset. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 70 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS - SELCAL INDICATIONS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 23 - COMMUNICATIONS Issue 6 - January 2023 Page 71 of 228 BOMBARDIER DHC 8-400 (PWC PW150) COMMUNICATIONS SELECTIVE CALLING (SELCAL) INTERFACES The left main bus energizes the SELCAL decoder with 28V DC electrical power through a 2 Ampere circuit breaker. The circuit breaker is located on the 28V DC avionics circuit breaker panel at position K2. TESTS A self-test makes sure that the decoder is operating correctly by simulating a call on each channel. The test pushbutton switch on the decoder front-panel is pushed to start the SELCAL self-test mode. The SELCAL test gives these indications: • • A decoder front-panel LED comes on for 3 seconds for each channel The green GO LED comes on if the system is serviceable and the NO GO LED