DOC AIRBUS | AMM A320FVHF SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The Very High Frequency (VHF) system is used for all short-range voice communications between:
The aircraft is equipped with three identical VHF systems which are fully independent:
The VHF system has data link functions which are defined by ARINC 750-4:
The Very High Frequency (VHF) system is used for all short-range voice communications between:
- Different aircraft in flight
- Aircraft (in flight or on the ground) and ground stations.
The aircraft is equipped with three identical VHF systems which are fully independent:
- VHF1
- VHF2
- VHF3.
The VHF system has data link functions which are defined by ARINC 750-4:
- Mode A
- Mode 2.
A. Mode A:
Many aircraft using data link communication have a VHF Data Link (VDL) mode A function. This function allows a 2400 bit/s rate throughput through an Amplitude-Modulation Minimum Shift-Keying.
Once the dialogue between the VHF Data Radio (VDR) transceiver and the ATSU is established (exchange protocol Williamsburg V1 initialized), the two systems can exchange data in mode A.
Many aircraft using data link communication have a VHF Data Link (VDL) mode A function. This function allows a 2400 bit/s rate throughput through an Amplitude-Modulation Minimum Shift-Keying.
Once the dialogue between the VHF Data Radio (VDR) transceiver and the ATSU is established (exchange protocol Williamsburg V1 initialized), the two systems can exchange data in mode A.
B. Mode 2:
The VDL mode 2 function is used to reduce the channel saturation. With this function, the rate throughput is increased ten times through a D8-PSK modulation (31.5 kbit/s).
The VDL mode 2 function is used to reduce the channel saturation. With this function, the rate throughput is increased ten times through a D8-PSK modulation (31.5 kbit/s).
NOTE: The VDL mode 2 data link function includes these two ACARS subnetworks:
- AOA
- ATN.
The AOA subnetwork is used now and the ATN subnetwork will be used in the future.
2. Component Location
VHF System - Component Location ** ON A/C NOT FOR ALL
VHF System - Component Location ** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL VHF System - Component Location ** ON A/C NOT FOR ALL VHF System - Component Location ** ON A/C NOT FOR ALL | FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||||
| 1RC1 | XCVR-VHF, 1 | 81VU | 127 | 23-12-33 | |
| 1RC2 | XCVR-VHF, 2 | 82VU | 128 | 23-12-33 | |
| 1RC3 | XCVR-VHF, 3 | 81VU | 127 | 23-12-33 | |
| 4RC1 | ANTENNA-VHF, 1 | 220 | 23-12-11 | ||
| 4RC2 | ANTENNA-VHF, 2 | 152 | 23-12-11 | ||
| 4RC3 | ANTENNA-VHF, 3 | 250 | 23-12-11 | ||
3. System Description
Each VHF system has:
Each VHF system has an interface with the following systems and components:
Each VHF system has:
- A transceiver
- An antenna.
Each VHF system has an interface with the following systems and components:
- Radio Management Panels (RMP)
- Audio Management Unit (AMU)
- Centralized Fault Display Interface Unit (CFDIU)
- Landing Gear Control and Interface Unit (LGCIU)
- System Data Acquisition Concentrators (SDAC)
- Air Traffic Service Unit (ATSU).
A. Interface with the RMPs
The RMPs are centralized systems used for the selection of the frequency/channel and the display of the VHF system. They are also used to switch between the voice/data modes (Ref. 23-13).
The RMPs are centralized systems used for the selection of the frequency/channel and the display of the VHF system. They are also used to switch between the voice/data modes (Ref. 23-13).
B. Interface with the AMU
The AMU is used for the connection to the audio integrating and Selective Calling (SELCAL) systems by means of the Audio Control Panels (ACP) (Ref. 23-51).
The AMU is used for the connection to the audio integrating and Selective Calling (SELCAL) systems by means of the Audio Control Panels (ACP) (Ref. 23-51).
C. Interface with the CFDIU
The CFDIU is a centralized maintenance system (Ref. 31-32). Through its interface with the CFDIU, the VHF3 transceiver sends fault reports to the ground.
The CFDIU is a centralized maintenance system (Ref. 31-32). Through its interface with the CFDIU, the VHF3 transceiver sends fault reports to the ground.
D. Interface with the LGCIU
In case of CFDIU failure, the LGCIU gives the aircraft status (in flight or on the ground) to the VHF BITE (Ref. 32-31).
In case of CFDIU failure, the LGCIU gives the aircraft status (in flight or on the ground) to the VHF BITE (Ref. 32-31).
E. Interface with the SDACs
The SDACs receive the transmission information from the VHF system with the KEY EVENT output of the VHF transceiver and record the transmit mode.
When the SDACs sense that the VHF transmits information (the PTT pushbutton switch is pushed) for 30 seconds, a "beep-beep" aural warning is heard each second for five seconds.
After 35 seconds, the transmission automatically stops.
After 25 seconds, if the PPT pushbutton switch stays pushed, the "VHF-X EMITTING" message comes into view on the ECAM Display Unit (DU).
To start a new transmission, the operator must release the PTT pushbutton switch and push it again.
Data communications stop when the RMP or the Multipurpose Control & Display Unit (MCDU) changes from data mode to voice mode.
The SDACs receive the transmission information from the VHF system with the KEY EVENT output of the VHF transceiver and record the transmit mode.
When the SDACs sense that the VHF transmits information (the PTT pushbutton switch is pushed) for 30 seconds, a "beep-beep" aural warning is heard each second for five seconds.
After 35 seconds, the transmission automatically stops.
After 25 seconds, if the PPT pushbutton switch stays pushed, the "VHF-X EMITTING" message comes into view on the ECAM Display Unit (DU).
To start a new transmission, the operator must release the PTT pushbutton switch and push it again.
Data communications stop when the RMP or the Multipurpose Control & Display Unit (MCDU) changes from data mode to voice mode.
NOTE: The Flight Warning System (FWS) standard installed in the aircraft can cause change of the data communication behavior.
F. Interface with the ATSU
If the VHF3 transceiver is in data mode, the ATSU sends data to the VHF system for data communication. In voice mode, the VHF3 transceiver is monitored by the RMP (valid only if the ATSU is available).
If the VHF3 transceiver is in data mode, the ATSU sends data to the VHF system for data communication. In voice mode, the VHF3 transceiver is monitored by the RMP (valid only if the ATSU is available).
A. VHF1 System
VHF1 system is supplied with 28VDC:
VHF1 system is supplied with 28VDC:
- From the 28VDC ESS BUS 4PP (sub-busbar 401PP)
- Through circuit breaker 2RC1 located on the overhead panel 49VU, in the cockpit.
B. VHF2 System
VHF2 system is supplied with 28VDC:
VHF2 system is supplied with 28VDC:
- From the 28VDC BUS2 2PP (sub-busbar 204PP)
- Through circuit breaker 2RC2 located on the rear panel 121VU, in the cockpit.
C. VHF3 System
VHF3 system is supplied with 28VDC:
VHF3 system is supplied with 28VDC:
- From the 28VDC BUS1 1PP (sub-busbar 101PP)
- Through circuit breaker 2RC3 located on the rear panel 121VU in the cockpit.
5. Interface
A. Output Interface
(1) Digital Outputs
The connections with the CFDIU is a type-1 system. This type of system has an ARINC 429 input from the CFDIU and an ARINC 429 output. This system is thus capable of two-way communication with the CFDIU (Ref.31-32).
The radio-communication equipment receives the frequency data through words from the RMPs. These words have a structure and a refresh rate defined in ARINC 429 characteristics specification.
On the output bus, each VHF transceiver transmits the labels 354, 356, 377, and only VHF3 transceiver transmits labels 270 and 172.
This table contains all the output parameters in the digital form.
They are sorted as per the numerical order of their output label.
The equipment code of the VHF transceiver is 016.
An ARINC 429 HS bus between VHF3 (VDR3) and ATSU is used to transmit user's data and control data.
The connections with the CFDIU is a type-1 system. This type of system has an ARINC 429 input from the CFDIU and an ARINC 429 output. This system is thus capable of two-way communication with the CFDIU (Ref.31-32).
The radio-communication equipment receives the frequency data through words from the RMPs. These words have a structure and a refresh rate defined in ARINC 429 characteristics specification.
On the output bus, each VHF transceiver transmits the labels 354, 356, 377, and only VHF3 transceiver transmits labels 270 and 172.
This table contains all the output parameters in the digital form.
They are sorted as per the numerical order of their output label.
| ------------------------------------------------------------------------------- |
| | PARAMETER LIST PARAMETER CHARACTERISTICS (NUMERIC) | |
| ------------------------------------------------------------------------------- |
| |EQ.SYS.LAB.SDI|PARAMETER | WORD RANGE |UNIT|SIG |BITS|XMSN|CODE|ALPHA|SOURCE | |
| | |DEFINITION| OPER RANGE | |BIT | |INTV| |CODE |ORIGIN | |
| | |(*=REMARK)| RESOLUTION | | | | | | |BUS No.| |
| | |(X=NOTE) | ACCURACY | | | | | | |ATA REF| |
| | | | | | | | | | |CONV | |
| ------------------------------------------------------------------------------- |
| ! 354 !LRU ! ! ! ! ! ! ! ! ! |
| ! !IDENT ! ! ! ! ! 250!ISO5! ! ! |
| ! ! ! ! ! ! ! ! ! ! ! |
| ! 377 !EQUIP ! ! ! ! ! ! ! ! ! |
| ! !IDENT ! ! ! ! !1000! BCD! ! ! |
| ! ! ! ! ! ! ! ! ! ! ! |
| ! 356 !FAULT ! ! ! ! ! ! ! ! ! |
| ! !MESSAGE ! ! ! ! ! 250!ISO5! ! ! |
| ! ! ! ! ! ! ! ! ! ! ! |
| ! 270 !STATUS ! ! ! ! !1000!BOO-! ! ! |
| ! ! ! ! ! ! ! !LEAN! ! ! |
| ! ! ! ! ! ! ! !WORD! ! ! |
| ! 172 !SAL MODE ! ! ! ! !1000! BNR! ! ! |
| ------------------------------------------------------------------------------- |
The equipment code of the VHF transceiver is 016.
An ARINC 429 HS bus between VHF3 (VDR3) and ATSU is used to transmit user's data and control data.
(2) Output Discretes
These output discretes are the same for each VHF circuit.
These output discretes are the same for each VHF circuit.
| ------------------------------------------------------------------------------- |
| NAME ELECTRICAL LEVEL TO SIGNAL STATUS |
| ------------------------------------------------------------------------------- |
| KEY EVENT GND/O.C. SDAC GND=EMISSION |
(3) Output Analog Signals
These output analog signals are the same for each VHF circuit.
These output analog signals are the same for each VHF circuit.
| ------------------------------------------------------------------------------- |
| NAME ELECTRICAL LEVEL TO SIGNAL STATUS |
| ------------------------------------------------------------------------------- |
| AUDIO SIDETONE OUTPUT MODULATION AMU |
| SELCAL OUTPUT MODULATION AMU |
6. Component Description
A. VHF Transceiver - Description FIN: 1-RC-1 FIN: 1-RC-2 FIN: 1-RC-3
The VHF (VDR) transceiver conforms to ARINC 600 specifications.
The case size is 3MCU.
The VHF (VDR) transceiver conforms to ARINC 600 specifications.
The case size is 3MCU.
(1) VHF transceiver face
The face features:
The face features:
- Two jacks (PHONE and MIC)
- A TEST pushbutton switch
- A red/green warning light: LRU STATUS
- A red indicator light: CONTROL FAIL
- A red warning light: ANTENNA FAIL
- A handle
- An identification plate.
(2) VHF transceiver back
The back comprises three connectors to enable connection with:
The back comprises three connectors to enable connection with:
- The automatic test circuits (Top Plug TP)
- The peripheral systems (Middle Plug MP)
- The antenna and the power supply circuits (Bottom Plug BP).
B. VHF (VDR) Transceiver - Characteristics
The VHF transceiver complies with the standards defined in ARINC 716.
The transmission and reception of coded messages between the various control units (CFDIU and RMP) comply with ARINC 429.
The transceiver operates within the frequency range between 118.000 and 136.975 MHz with 25KHz spacing between channels (it has a possibility of 760 channels).
The VHF transceiver complies with the standards defined in ARINC 716.
The transmission and reception of coded messages between the various control units (CFDIU and RMP) comply with ARINC 429.
The transceiver operates within the frequency range between 118.000 and 136.975 MHz with 25KHz spacing between channels (it has a possibility of 760 channels).
C. VHF (VDR) transceiver - Operation
(1) General Operation
The VHF transceiver ensures its primary functions through:
The purpose of this test is to test the front panel LEDs and to test the functioning of the radio. The color of the LEDs in the fourth phase indicate the result of the self-test. The duration of the LED illumination is for reference only.
The VHF transceiver ensures its primary functions through:
- The receiver
- The transmitter
- The synthesizer
- The FM Immunity filter is a high-pass with a stop band attenuation at 108 MHz greater than 10 dB. This filter prevents interference from high-power FM broadcast stations.
- Route the input signal from the antenna to the receiver in the receive mode
- Connect the transmitter RF output to the antenna in the transmit mode.
The purpose of this test is to test the front panel LEDs and to test the functioning of the radio. The color of the LEDs in the fourth phase indicate the result of the self-test. The duration of the LED illumination is for reference only.
| --------------------------------------------------------------------------- |
| ! PHASE ! LRU STATUS ! CONTROL FAIL ! ANTENNA FAIL ! DURATION ! |
| --------------------------------------------------------------------------- |
| ! 1 ! RED ! RED ! RED ! 1-3 sec ! |
| ! 2 ! GREEN ! RED ! RED ! 1-3 sec ! |
| ! 3 ! OFF ! OFF ! OFF ! 1-3 sec ! |
| ! 4 ! GREEN ! OFF ! OFF ! 20-40 sec ! |
D. VHF Antenna
(1) Description
The VHF antenna is a white blade antenna. It weighs 1.2 kg.
This antenna is composed of:
The VHF antenna is a white blade antenna. It weighs 1.2 kg.
This antenna is composed of:
- An aluminum base plate
- A laminated radome
- A duralinox leading edge
- A C-type coaxial connector surrounded by a seal.
(2) Operation
The VHF antenna, the height of which corresponds to a quarter of the wavelength, provides a quasi-omnidirectional radiation.
This antenna allows the transmission and reception of VHF signals over the 116 to 156 MHz frequency range. Its impedance is 50 ohms and its standing-wave ratio is lower than 2 over the 118 to 137 MHz VHF frequency range.
The VHF antenna, the height of which corresponds to a quarter of the wavelength, provides a quasi-omnidirectional radiation.
This antenna allows the transmission and reception of VHF signals over the 116 to 156 MHz frequency range. Its impedance is 50 ohms and its standing-wave ratio is lower than 2 over the 118 to 137 MHz VHF frequency range.
7. Operation
A. Receive Function
The antenna picks up the VHF radio-communication signals from the stations. These signals are transmitted to the transceiver by a coaxial cable.
In voice mode, the transceiver, tuned on the frequency selected on one RMP (Ref. 23-13) demodulates the VHF received signals into Audio Frequency (AF) signals.
The AF signals are transmitted to the audio equipment or SELCAL system through the AMU.
In data mode, the transceiver tuned on the frequency selected on one MCDU and transmitted to the transceiver through an ARINC 429 HS bus, demodulates the VHF3 received signals into digital information. This information is transmitted to the ATSU through an ARINC 429 HS bus.
The antenna picks up the VHF radio-communication signals from the stations. These signals are transmitted to the transceiver by a coaxial cable.
In voice mode, the transceiver, tuned on the frequency selected on one RMP (Ref. 23-13) demodulates the VHF received signals into Audio Frequency (AF) signals.
The AF signals are transmitted to the audio equipment or SELCAL system through the AMU.
In data mode, the transceiver tuned on the frequency selected on one MCDU and transmitted to the transceiver through an ARINC 429 HS bus, demodulates the VHF3 received signals into digital information. This information is transmitted to the ATSU through an ARINC 429 HS bus.
B. Transmit Function
In voice mode, the AF signals from the microphones are transmitted to the VHF transceiver through the AMU.
The VHF transceiver tuned on the frequency selected on one RMP, modulates the AF signals into VHF signals. These VHF signals are sent to the antenna by a coaxial cable. They are then transmitted to the various stations.
The VHF system sends the transmission information to the SDACs through the KEY EVENT output of the VHF transceiver and the SDACs record the transmit mode.
In data mode, the digital information is transmitted from the ATSU to the VHF3 (tuned on the frequency selected on one MCDU and transmitted to the transceiver through an ARINC 429 HS bus) which modulates it.
The VHF signals are sent to the antenna by a coaxial cable. They are then transmitted to the various stations.
In voice mode, the AF signals from the microphones are transmitted to the VHF transceiver through the AMU.
The VHF transceiver tuned on the frequency selected on one RMP, modulates the AF signals into VHF signals. These VHF signals are sent to the antenna by a coaxial cable. They are then transmitted to the various stations.
The VHF system sends the transmission information to the SDACs through the KEY EVENT output of the VHF transceiver and the SDACs record the transmit mode.
In data mode, the digital information is transmitted from the ATSU to the VHF3 (tuned on the frequency selected on one MCDU and transmitted to the transceiver through an ARINC 429 HS bus) which modulates it.
The VHF signals are sent to the antenna by a coaxial cable. They are then transmitted to the various stations.
C. VHF Voice/Data Mode Selection
The system has direct control over the VHF3 switching between voice and data modes.
A voice/data switching can be requested by:
The system has direct control over the VHF3 switching between voice and data modes.
A voice/data switching can be requested by:
- Any RMP
- The MCDU through the Air Traffic and Information Management System (ATIMS) (Ref. 46-21).
D. VDL Ground Network
The VDL mode A and mode 2 functions provide a short-range Air/Ground VHF digital communication link (operated mainly by ARINC or SITA and by other secondary ground service providers) for the transmission of digital data. The VDL mode 2 function is available in the aircraft in parallel with VDL mode A function. Switching between the two modes (mode A, mode 2) is automatic without any action from the navigation crew (depending on the capacity of the selected provider and the ATSU configuration).
The VDL mode A and mode 2 functions provide a short-range Air/Ground VHF digital communication link (operated mainly by ARINC or SITA and by other secondary ground service providers) for the transmission of digital data. The VDL mode 2 function is available in the aircraft in parallel with VDL mode A function. Switching between the two modes (mode A, mode 2) is automatic without any action from the navigation crew (depending on the capacity of the selected provider and the ATSU configuration).
NOTE: Both functions (mode A, mode 2) cannot be used simultaneously.
A. Built-in-Test Equipment (BITE)
The BITE facilitates maintenance on in-service aircraft.
The BITE detects and determines a failure related to the VHF system.
The BITE of the VHF transceiver is connected to the Centralized Fault Display Interface Unit (CFDIU), refer to ATA 31-32.
The BITE:
The BITE facilitates maintenance on in-service aircraft.
The BITE detects and determines a failure related to the VHF system.
The BITE of the VHF transceiver is connected to the Centralized Fault Display Interface Unit (CFDIU), refer to ATA 31-32.
The BITE:
- Transmits permanently the VHF system status and an identification message to the CFDIU
- Memorizes the failures occurred during the last 63 flight legs
- Monitors data input from the various peripherals (RMP, CFDIU and ATSU)
- Transmits to the CFDIU, the result of the tests performed and the result of the self-tests
- Communicates with the CFDIU through menus.
B. General Operation
The BITE has two operation modes:
The BITE has two operation modes:
- The normal mode
- The menu mode.
(1) Normal mode
In normal mode, the BITE monitors cyclically the momentaneous status of the VHF system. It transmits these information signals to the CFDIU during the flight.
In case of fault detection, the BITE stores the information signals in the fault memories.
These information signals are transmitted to the CFDIU every 250 ms (max) through an ARINC 429 message with label 356.
In normal mode, the BITE monitors cyclically the momentaneous status of the VHF system. It transmits these information signals to the CFDIU during the flight.
In case of fault detection, the BITE stores the information signals in the fault memories.
These information signals are transmitted to the CFDIU every 250 ms (max) through an ARINC 429 message with label 356.
(2) Menu mode
The menu mode can only be activated on the ground.
This mode enables communication between the CFDIU and the VHF transceiver BITE, through the MCDU (maintenance menu).
In menu mode, the VHF menu gives access to these pages:
The menu mode can only be activated on the ground.
This mode enables communication between the CFDIU and the VHF transceiver BITE, through the MCDU (maintenance menu).
In menu mode, the VHF menu gives access to these pages:
- LAST LEG REPORT
- PREVIOUS LEGS REPORT
- LRU IDENTIFICATION
- GND SCANNING
- TROUBLE SHOOT DATA
- CLASS 3 FAULTS
- TEST
- GROUND REPORT.
C. Functional Description
(1) LAST LEG REPORT
This report contains the Class 1 and 2 internal and external faults recorded during the last flight.
This report contains the Class 1 and 2 internal and external faults recorded during the last flight.
(2) PREVIOUS LEGS REPORT
The messages shown on this report are identical to those given in the paragraph above but they are related to the faults that occurred during the last 63 flights.
The messages shown on this report are identical to those given in the paragraph above but they are related to the faults that occurred during the last 63 flights.
(3) LRU IDENTIFICATION
This report displays the Part Number (P/N) and the Serial Number (S/N).
This report displays the Part Number (P/N) and the Serial Number (S/N).
(4) GROUND SCANNING
This function is used to monitor and detect anomalies on the ground.
This function is used to monitor and detect anomalies on the ground.
(5) TROUBLE SHOOTING DATA
This function is used to analyze the snapshot of the recorded fault to detect any software bug. Two types of data are displayed on the MCDU:
This function is used to analyze the snapshot of the recorded fault to detect any software bug. Two types of data are displayed on the MCDU:
- Correlation parameters, which are the date and the UTC
- Snapshot data.
(6) CLASS 3 FAULTS
This report contains the Class 3 internal and external faults recorded during the last flight.
This report contains the Class 3 internal and external faults recorded during the last flight.
(7) TEST
A VHF built-in functional test can be initiated by pushing, on the MCDU, the line key adjacent to the TEST indication on the VHF maintenance sub-menu. The test sequence is shown in the figure.
A VHF built-in functional test can be initiated by pushing, on the MCDU, the line key adjacent to the TEST indication on the VHF maintenance sub-menu. The test sequence is shown in the figure.
(8) GROUND REPORT
This function is used to display Class 1, 2 or 3 internal faults when they are detected on the ground. These faults differ from these faults displayed in the LAST LEG REPORT and CLASS 3 FAULTS. The figure shows examples of internal faults recorded on the ground by the VHF system.
The BITE system is used through one of the two MCDUs 3CA1 and 3CA2 (Ref. ATA 22-82-00).
This function is used to display Class 1, 2 or 3 internal faults when they are detected on the ground. These faults differ from these faults displayed in the LAST LEG REPORT and CLASS 3 FAULTS. The figure shows examples of internal faults recorded on the ground by the VHF system.
The BITE system is used through one of the two MCDUs 3CA1 and 3CA2 (Ref. ATA 22-82-00).