W DOC AIRBUS | AMM A320F

ILS - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL
1. General
The primary function of the Multi-Mode Receiver (MMR) is to receive and process Instrument Landing System (ILS) and Global Positioning System (GPS) signals. The MMR is a navigation sensor with two internal receivers.
A. ILS Receiver
The function of the ILS is to provide the crew and airborne system users with lateral (Localizer (LOC)) and vertical (Glide Slope (G/S)) deviation signals, with respect to the approach ILS radio beam transmitted by a ground station.
The LOC operates in a frequency band which ranges from 108.1 MHz to 111.95 MHz and the G/S uses the band from 329.15 MHz to 335 MHz as defined by Aeronautical Radio Incorporated (ARINC) specification 710.
B. GPS Receiver
The GPS is a radio aid to worldwide navigation which provides:
  • The crew with a readout of accurate navigation information, e.g. position, track and speed
  • The Flight Management and Guidance Computer (FMGC) with position information, after hybridization in the Air Data/Inertial Reference Unit (ADIRU) with inertial parameters, for accurate position fixing.
** ON A/C NOT FOR ALL
2. Component Location
F MMR - Component Location ** ON A/C NOT FOR ALL
The MMR system units are located in the aircraft as follows:
FIN FUNCTIONAL
DESIGNATION		 PANEL ZONE ACCESS
DOOR		 ATA REF
** ON A/C NOT FOR ALL
3RT ANTENNA-LOCALIZER 1/2 110AL 110 34-36-11
4RT ANTENNA-GLIDE/SLOPE 1/2 110AL 110 34-36-18
** ON A/C NOT FOR ALL
3. System Description
F MMR - Monitoring and Display ** ON A/C NOT FOR ALL
F MMR - Data Acquisition ** ON A/C NOT FOR ALL
The aircraft comprises two independent MMRs (40RT1 and 40RT2) linked to:
  • A common LOC antenna (3RT)
  • A common G/S antenna (4RT)
  • A GPS active antenna (43RT1 (linked to MMR1))
  • A GPS active antenna (43RT2 (linked to MMR2)).
A. ILS Operation
The equipment given below can control the ILS operation:
  • The Multipurpose Control and Display Units (MCDU) and the FMGC for frequency/course selection in normal operating mode
  • The Radio Management Panels (RMP) for frequency/course selection in back-up mode.
The ILS data are shown on the Electronic Flight Instrument System (EFIS) displays:
  • The CAPT Primary Flight Display (PFD) and F/O Navigation Display (ND) show the deviations from the ILS 1.
  • The F/O PFD and CAPT ND show the deviations from the ILS 2.
The Morse-coded audio identification signals are sent to the Audio Management Unit (AMU). These signals can be heard in the boomset and on the loudspeaker according to the selection by the crew on the Audio Control Panel (ACP).
B. GPS Operation
(1) Normal operation
In normal operation, the GPS 1 data are used by the ADIRUs 1 and 3; the GPS 2 data by the ADIRU 2.
NOTE: In order to reduce GPS initialization time, the GPS 1(2) receives data from the ADIRU 1(2).

The Inertial Reference (IR) portion of the ADIRU 1(2) provides the FMGC 1(2) with:
  • Pure IR data
  • Pure GPS data (in this case, the ADIRU operates as a relay)
  • Hybrid Global Positioning and Inertial Reference System (GPIRS) data.
    The hybrid GPIRS 1(2) data are used by the FMGC 1(2) for position fixing purposes.
    The pure GPS data are used for display on the MCDUs 1 and 2.

In case of one GPS failure, the three ADIRUs automatically select the only operative GPS to compute hybrid GPIRS data.
In case of ADIRU 1 failure, the FMGC 1 uses ADIRU 3/GPS 1 data.
In case of ADIRU 2 failure, the FMGC 2 uses ADIRU 3/GPS 2 data.
NOTE: The primary source of the ADIRU 3 being the GPS 1, it is necessary to select the secondary input port of the ADIRU 3 (GPS 2) by means of the ATT HDG selector switch (13FP) to preserve side 1/side 2 segregation (GPS 1/ADIRU 1/FMGC 1 and GPS 2/ADIRU 3/FMGC 2 architecture).
In case of failure of two ADIRUs, the two FMGCs use only the operative ADIRU.
This ADIRU receives data from its own side GPS (e.g. ADIRU 1 - GPS 1).
C. Maintenance Operation
The MMR system provides the Centralized Fault Display Interface Unit (CFDIU) with an interface for onboard testing and fault reporting purposes. The MCDUs show the maintenance data.
** ON A/C NOT FOR ALL
4. Power Supply
Each MMR system is energized through 115VAC busbars as follows:
  • 401XP for system 1
  • 204XP for system 2.
    The system is supplied through these circuit breakers:

A. Circuit Breakers Table
PANELDESIGNATIONFINLOCATION
** ON A/C NOT FOR ALL
49VUNAV/MMR/142RT1G12
121VUCOM NAV/MMR/242RT2L07
** ON A/C NOT FOR ALL
5. Interface
A. ILS Interface
(1) ILS digital outputs
The ILS transmits data in compliance with the low speed ARINC 429 standards. The table below contains all the output parameters in numerical form.
-------------------------------------------------------------------------------
| 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 |
-------------------------------------------------------------------------------
! 173 ! LOCALIZER!+ or - 0.155!DDM ! 29 ! 12 ! 50 !BNR ! ! !
! ! DEVIATION! ! ! ! ! ms ! ! ! !
! ! ! ! ! ! ! ! ! ! !
! 174 ! GLIDE !+ or - 0.175!DDM ! 29 ! 12 ! 50 !BNR ! ! !
! ! SLOPE ! ! ! ! ! ms ! ! ! !
! ! DEVIATION! ! ! ! ! ! ! ! !
! ! ! ! ! ! ! ! ! ! !
! 033 ! ILS !FROM 108.10 !MHz ! ! 15 !200 !BCD ! ! !
! ! FREQUENCY! TO 111.95 ! ! ! ! ms ! ! ! !
! ! ! ! ! ! ! ! ! ! !
! 017 ! RUNWAY ! FROM 0 TO !Deg.! ! 15 !300 !BCD ! ! !
! ! HEADING ! 359.9 ! ! ! ! ms ! ! ! !
! ! ! ! ! ! ! ! ! ! !
! 105 ! RUNWAY ! FROM 0 TO !Deg.! ! 11 !300 !BNR ! ! !
! ! HEADING ! 359.9 ! ! ! ! ms ! ! ! !
! ! ! ! ! ! ! ! ! ! !
! 263 !ILS GROUND! ! ! ! 14 !150 !HYB ! ! !
! ! STATION ! ! ! ! ! ms ! ! ! !
! ! IDENT ! ! ! ! ! ! ! ! !
! ! ! ! ! ! ! ! ! ! !
! 264 !ILS GROUND! ! ! ! 14 !150 !HYB ! ! !
! ! STATION ! ! ! ! ! ms ! ! ! !
! ! IDENT ! ! ! ! ! ! ! ! !
! ! ! ! ! ! ! ! ! ! !
! 271 ! MMR ! ! ! ! 19 !400 !DISC! ! !
! ! DISCRETE ! ! ! ! ! ms ! ! ! !
-------------------------------------------------------------------------------

B. GPS Interface
(1) GPS digital outputs
The GPS has three independently buffered high-speed ARINC 429 digital output buses connected to the three ADIRUs.
The table below contains all the output parameters in numerical form.
-------------------------------------------------------------------------------
| 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 |
-------------------------------------------------------------------------------
! ! ! ! ! ! ! ! ! !
! 060 ! MEASURE- ! Pack ! N/A! N/A! ! 1s ! ! !
! ! MENT STS ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! !+/-268435456! ! ! ! ! ! !
! 061 ! PSEUDO ! 256 ! M ! 20 ! ! 1s !BNR ! !
! ! RANGE ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! 062 ! PSEUDO ! 256 ! M ! 11 ! ! 1s !BNR ! !
! ! RANGE ! 0.125 ! ! ! ! ! ! !
! ! FINE ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! 063 ! RANGE ! +/-4096 ! M/S! 20 ! ! 1s !BNR ! !
! ! RATE ! 0.0039 ! ! ! ! ! ! !
! ! ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ! ! ! ! ! ! ! !
! 064 ! DELTA ! +/-4096 ! M ! 20 ! ! 1s !BNR ! !
! ! RANGE ! 0.0039 ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ! ! ! ! ! ! ! !
! 065 ! SV POS X ! +/-67108864! M ! 20 ! ! 1s !BNR ! !
! ! ! 64 ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ! ! ! ! ! ! ! !
! 066 ! SV POS X ! 64 ! M ! 14 ! ! 1s !BNR ! !
! ! FINE ! 0.0039 ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ! +/-67108864! ! ! ! ! ! !
! 070 ! SV POS Y ! 64 ! M ! 20 ! ! 1s !BNR ! !
! ! ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ! ! ! ! ! ! ! !
! 071 ! SV POS Y ! 64 ! M ! 14 ! ! 1s !BNR ! !
! ! FINE ! 0.0039 ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ! ! ! ! ! ! ! !
! 072 ! SV POS Z ! +/-67108864! M ! 20 ! ! 1s !BNR ! !
! ! ! 64 ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ! ! ! ! ! ! ! !
! 073 ! SV POS Z ! 64 ! M ! 14 ! ! 1s !BNR ! !
! ! FINE ! 0.0039 ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! UTC MEA- ! 10.0 ! ! ! ! ! ! !
! 074 ! SURE TIME! 9.536743 ! S ! 20 ! ! 1s !BNR ! !
! ! ! micro sec ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! GPS ALT ! +/-131072 ! ! ! ! ! ! !
! 076 ! (MSL) ! 0.125 ! Ft ! 20 ! ! 1s !BNR ! !
! ! ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ! 1024 ! ! ! ! ! ! !
! 101 ! HDOP ! 0.031 ! N/A! 15 ! ! 1s !BNR ! !
! ! ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ! 1024 ! ! ! ! ! ! !
! 102 ! VDOP ! 0.031 ! N/A! 15 ! ! 1s !BNR ! !
! ! ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! GPS TRACK! +/-180 ! ! ! ! ! ! !
! 103 ! ANGLE ! 0.0055 ! Deg! 15 ! ! 1s !BNR ! !
! ! ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! GPS ! +/-180 ! ! ! ! ! ! !
! 110 ! LATITUDE ! 0.000172 ! Deg! 20 ! ! 1s !BNR ! !
! ! ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! GPS ! +/-180 ! ! ! ! ! ! !
! 111 ! LONGITUDE! 0.000172 ! Deg! 20 ! ! 1s !BNR ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! GPS ! 4096 ! ! ! ! ! ! !
! 112 ! GROUND ! 0.125 ! Kts! 15 ! ! 1s !BNR ! !
! ! SPEED ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! GPS ! 0.000172 ! ! ! ! ! ! !
! 120 ! LATITUDE ! 8.38 E-8 ! Deg! 11 ! ! 1s !BNR ! !
! ! FINE ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! GPS ! 0.000172 ! ! ! ! ! ! !
! 121 ! LONGITUDE! 8.38 E-8 ! Deg! 11 ! ! 1s !BNR ! !
! ! FINE ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! 125 ! UTC ! 23:59.9 !HR: ! 5 ! ! 1s !BCD ! !
! ! ! 0.1 MIN !MIN ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! !HORIZONTAL! 16 ! NM ! 17 ! ! 1s !BNR ! !
! 130 ! INTEGRITY! 0.00012 ! ! ! ! ! ! !
! ! LIMIT ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! VERTICAL ! 32768 ! Ft ! 17 ! ! 1s !BNR ! !
! 133 ! INTEGRITY! 0.25 ! ! ! ! ! ! !
! ! LIMIT ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! VERTICAL ! 32768 ! ! ! ! ! ! !
! 136 ! FIGURE ! 0.125 ! Ft ! 18 ! ! 1s !BNR ! !
! ! OF MERIT ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ! 1.0 ! ! ! ! ! ! !
! 140 ! UTC FINE ! 0.9536743 ! S ! 20 ! ! 1s !BNR ! !
! ! ! micro sec ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! UTC FINE ! 0.953674 ! S ! 10 ! ! 1s !BNR ! !
! 141 ! FRACTIONS! micron s ! ! ! ! ! ! !
! ! ! 0.9313225ns! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! APPROACH ! 16 ! NM ! 17 ! ! 1s !BNR ! !
! 143 ! AREA ! 0.00012 ! ! ! ! ! ! !
! ! HIL ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! APPROACH ! 32768 ! Ft ! 17 ! ! 1s !BNR ! !
! 144 ! AREA ! 0.25 ! ! ! ! ! ! !
! ! HIL ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ! !HR: ! ! ! ! ! !
! 150 ! UTC ! 23:59:59 !MIN:! 17 ! ! 1s !BNR ! !
! ! ! 1.0 s !S ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! 162 ! DEST ! 23:59 !HR: ! 11 ! !0.5s!BNR ! !
! ! ETA ! 1 MIN !MIN ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! 163 ! ALT ! 23:59 !HR: ! 11 ! !0.5s!BNR ! !
! ! WAYPNT ! 1 MIN !MIN ! ! ! ! ! !
! ! ETA ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! VERTICAL ! +/-32768 ! Ft/! ! ! ! ! !
! 165 ! VELOCITY ! 1.0 !MIN ! 15 ! ! 1s !BNR ! !
! ! ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! N/S ! +/-4096 ! ! ! ! ! ! !
! 166 ! VELOCITY ! 0.125 ! Kts! 15 ! ! 1s !BNR ! !
! ! ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! E/W ! +/-4096 ! ! ! ! ! ! !
! 174 ! VELOCITY ! 0.125 ! Kts! 15 ! ! 1s !BNR ! !
! ! ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! 226 ! DATA ! N/A !N/A !N/A ! !N/A !ISO ! !
! ! LOADER ! ! ! ! ! !#5 ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! !HORIZONTAL! 16 ! ! ! ! ! ! !
! 247 ! FIGURE ! 6.1E-5 ! NM ! 18 ! ! 1s !BNR ! !
! ! OF MERIT ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ! N/A !DAY:! ! ! ! ! !
! 260 ! DATE ! 1 Day !MON:! 6 ! ! 1s !BCD ! !
! ! ! !YEAR! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! GPS ! ! ! ! ! ! ! !
! 273 ! SENSOR ! N/A !N/A !N/A ! ! 1s !DISC! !
! ! STATUS ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! 343 ! DEST ! 16 !NM ! 11 ! !0.5s!BNR ! !
! ! HIL ! 0.0078 ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! ALT ! ! ! ! ! ! ! !
! 347 ! WAYPNT ! 16 !NM ! 11 ! !0.5s!BNR ! !
! ! HIL ! 0.0078 ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! 354 ! GPSSU ! N/A !N/A !N/A ! ! !ISO ! !
! ! IDENT ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! 356 ! MAINT ! N/A !N/A !N/A ! ! !ISO ! !
! ! DATA ! ! ! ! ! ! ! !
!--------------!----------!------------!----!----!----!----!----!-------------!
! ! EQUIP- ! ! ! ! ! ! ! !
! 377 ! MENT ! N/A !N/A !N/A ! ! 1s !BCD ! !
! ! ID ! ! ! ! ! ! ! !
-------------------------------------------------------------------------------

** ON A/C NOT FOR ALL
6. Component Description
A. MMR - External Description FIN: 40-RT-1 FIN: 40-RT-2
F MMR - External Description ** ON A/C NOT FOR ALL
The face of the MMR is fitted with a handle, two attaching parts, a TEST pushbutton switch and three LEDs. The LRU STATUS LED has two colors (red/green).
The three LEDs have the following name, color and function:
  • LRU STATUS (red) indicates that an internal fault is detected during the front panel self-test sequence
  • LRU STATUS (green) indicates that no internal fault is detected during the front panel self-test sequence
  • CONTROL FAIL (red) indicates that no control input is available during the test sequence.
  • ANT FAIL (red) indicates that a failed antenna is detected during the test sequence.
The back of the MMR is equipped with one ARINC 600 size one connector, which includes three plugs:
  • Top Plug (TP): connection with the GPS antenna
  • Middle Plug (MP): service interconnection
  • Bottom Plug (BP): connection with the power supply circuit and the LOC and G/S coaxial interconnections.
B. MMR - Internal Description FIN: 40-RT-1 FIN: 40-RT-2
F MMR - Block Diagram ** ON A/C NOT FOR ALL
The MMR consists of four parts:
  • The power supply unit
  • The ILS receiver
  • The GPS receiver
  • The system processor unit.
The primary function of the MMR is to receive and process ILS and GPS signals. The ILS receiver and the GPS receiver make up two of the sub-assemblies. The ILS signals, including both LOC and G/S, are used to determine flight path deviations during precision approach and landing, and are supplied to the aircraft flight control and instrument systems. These deviations are based on Radio Frequency (RF) signals that the unit receives from a ground-based ILS.
The GPS receiver simultaneously tracks signals from up to twelve GPS satellites. The signals are processed to generate a three-dimensional position and a precise time. The receiver generates an estimate of the positional accuracy provided. An integrity alert is activated if an unannounced satellite malfunction is detected. The receiver has the capability of excluding satellites that are malfunctioning.
The system processor card has functions that follow:
  • Output position and deviation data to other aircraft systems
  • Receive ILS frequency selections
  • Receive ADIRU & FMGC data for GPS initialization
  • Dialog with the CFDIU.

(1) Power supply
The aircraft supplies the 115 VAC, 400 Hz, single phase power to the MMR. The input power is routed from the rear interconnect to the forward power supply. The forward power supply provides power factor corrections and outputs +200 VDC for the aft power supply. The aft power supply steps the +200 VDC down to +/- 6.5 and +/- 13.5 VDC outputs. These unregulated voltages are routed to the other sub-assemblies where they are post-regulated to +/- 5 VDC and +/- 12 VDC. Post-regulation provides a level of separation between the subassemblies and possible noise on the power lines. It will also allow shut-off of the circuit areas when not needed for a specific phase of flight (not used today).

(2) ILS receiver
The MMR receives VHF LOC and UHF G/S signals at the antenna jacks in the bottom plug of the rear connector. Coaxial cables route the RF from the rear connector to the ILS receiver. The ILS receiver includes four functional areas:
  • VHF receiver
  • UHF receiver
  • Primary instrumentation processor
  • Monitor instrumentation processor.

    The VHF receiver filters, mixes and amplifies VHF signals. The resulting intermediate frequency signals are converted into serial data and processed by both the primary and the monitor instrumentation circuits. The UHF receiver filters, mixes, amplifies and detects UHF signals. The detected signals are converted into serial data and processed by the instrumentation processors. The primary instrumentation processor outputs flight path deviations to the system processor. The system processor forwards the flight path deviations to the aircraft instrumentation and auto-pilot computers (FMGC).
    The monitor instrumentation processor performs a validity check of the primary instrumentation processor deviation output and disables the outputs if the check fails. The primary and monitor instrumentation processors use ARINC 429 buses for intercommunications and for communications with the system processor.

(3) GPS receiver
The MMR receives RF signals through an active GPS antenna (preamplifier implemented within the antenna). The GPS receiver filters, mixes and performs analog-to-digital conversions. The resulting data is processed by microprocessors that output position, velocity, time and integrity data to the system processor. The system processor transmits ARINC 743A-compliant data for use by other aircraft systems. The GPS receiver also outputs a time mark discrete signal that tells users of the ARINC 743A data, the instant in time when the position solution is valid.

(4) System processor
The system processor controls the flow of data to the ILS and GPS receivers including mode and frequency selections, GPS initialization and maintenance data requests. The system processor also controls the transmission of output data including ILS deviation, GPS position, velocity, time, integrity, time marks and maintenance data. Circuitry on the system processor converts received data from serial to parallel and also formats parallel data to serial data for the transmission on the bus.
C. GPS Antenna FIN: 43-RT-1 FIN: 43-RT-2
F GPS Active - Antenna ** ON A/C NOT FOR ALL
Two L-Band antennas are mounted on the top of the fuselage, at the centerline, to receive signals from the GPS satellites. The GPS antenna is an active antenna with an integrated preamplifier and filter. It receives GPS signals at 1575.42 MHz and matches to a 50 ohms coaxial cable at the input to the MMR. The antenna has a right-hand circular polarized and omnidirectional radiation pattern.
The power supply of the preamplifier is provided by the MMR through the coaxial cable.
NOTE: The antenna connectors have a hole to install a lockwire and safety the coaxial cable.
D. Localizer Antenna FIN: 3-RT
F ILS - Antennas ** ON A/C NOT FOR ALL
The localizer antenna is an airborne antenna used to receive LOC signals in the 108-112MHz range. It is a folded half-loop type driven by capacitive coupling. The antenna has two independent RF connectors used to feed two independent ILS receivers. Connector separation is provided by a hybrid junction in the antenna.
E. Glide Slope Antenna
F ILS - Antennas ** ON A/C NOT FOR ALL
The G/S slope antenna is an airborne antenna used to receive GLIDE signals in the 329-335MHz range. It is a folded half-loop type driven by capacitive coupling. The antenna has two independent RF connectors used to feed two independent ILS receivers. Connector separation is provided by a hybrid junction in the antenna.
** ON A/C NOT FOR ALL
7. Operation
A. ILS Operation
(1) Normal operation
F MMR - Control and Indicating ** ON A/C NOT FOR ALL
Each MMR is connected to one RMP. The MMR 1 is connected to the RMP 1 (the MMR 2 to the RMP 2). The MMR 1 receives management bus from the FMGC 1 through the RMP 1 (the MMR 2 from the FMGC 2 through the RMP 2).
In normal operation, the FMGC 1(2) tunes the MMR 1(2) either automatically or manually by means of the MCDU. In this case, the RMP 1(2) operates as a relay which sends the frequency information from the FMGC 1(2) to the receiver 1(2).
Via a second port, the MMR 1(2) receives a second management bus (ILS FREQ + RWY HDG) directly from the FMGC 2(1).
The receiver selects one of the two input ports according to the FREQ/FUNCT DATA SOURCE SEL discrete signal, which is received from the FMGC 1(2) through the RMP 1(2).
(2) Operation in case of failure
With the failure of one FMGC, the second FMGC automatically controls the two MMRs, the off side directly and the on side through its RMP.
With the failure of the RMP 1(2) or two RMPs, the RMP concerned is transparent to data and discrete from FMGC.
(3) Manual operation
In manual operation (at any time or with failure of two FMGCs), the RMP 1 can control the MMR 1 after ON NAV mode selection. Same possibility for the RMP 2 (MMR 2).
F MMR - ILS - Course and Frequency Selection in Manual Mode ** ON A/C NOT FOR ALL
In this mode, the RMP 1 can control the MMR 2 through the RMP 2 after ON NAV mode selection on the RMP 2. Same possibility for RMP 2 through RMP 1.
After frequency selection, it is always necessary to select the associated course.
(4) Reconfiguration switching
In normal utilization, the ILS 1 data are shown on the CAPT PFD and the F/O ND; the ILS 2 data on the F/O PFD and the CAPT ND.
The Display Management Computer (DMC) 1 supplies data to the CAPT PFD and ND; the DMC 2 to the F/O PFD and ND.
With the failure of the DMC 1(2), it is possible to switch over to the DMC 3 with the Electronic Instrument System (EIS) DMC selector switch located on the panel 8VU, on the center pedestal.
In this case, the DMC 3 totally replaces the DMC 1(2) through the stage of the output switching relay of the failed DMC. With the failure of the PFD, there is an automatic transfer of the PFD image onto the ND.
With failure of the CAPT (F/O) ND, you get the transfer of the ND image onto the CAPT (F/O) PFD when you push the PFD/ND XFR pushbutton switch on panel 301VU (500VU).
When you set the PFD potentiometer to OFF on the panel 301VU (500VU), this causes:
  • Deactivation of the CAPT (F/O) PFD
  • Transfer of the PFD image onto the CAPT (F/O) ND.
(5) Audio control
The MMR applies its audio output to the Audio Integrating System (AIS). This system controls and directs the output to the headsets and/or the loudspeakers. AMU controls the audio level through the ACP. On the ACP, the pilot must push the ILS pushbutton switch and adjust the related potentiometer to the correct audio level.
With ILS/Distance Measuring Equipment (DME) co-allocated stations, the DME identification morse code can be listened in sequence with the ILS audio signal when you push the ILS pushbutton switch on the ACP and the ILS pushbutton switch on the Flight Control Unit (FCU).
(6) Data display
F MMR - ILS Data Display ** ON A/C NOT FOR ALL
(a) On the PFDs
On the right and below the attitude sphere, the deviation indications come into view in approach. These are:
  • The vertical deviation scale
  • The lateral deviation scale
  • The related aircraft deviation symbols.
If you select an ILS approach, the scales and symbols give G/S and LOC deviations. The scales come into view when you push the ILS pushbutton switch on the EFIS control section of the FCU. The deviation symbols come into view when the related G/S and LOC signals from the ILS receiver are valid.
If the ILS indications are available with the ILS pushbutton switch pushed, they have priority over the deviation information of the R NAV approach.
In this mode, the data given after are shown (item 5) in the left bottom corner:
  • ILS frequency (plus ILS identification if available)
  • ILS - DME distance.
At the top section of the PFD, a Flight Mode Annunciator (FMA) shows the various armed/active longitudinal and lateral modes:
Item 1: the G/S longitudinal modes are shown in the 2nd column (cyan for armed or green for active)
Item 2: the LOC longitudinal modes are shown in the 3rd column (cyan for armed or green for active)
VERTICAL DEVIATION (item 3)
The vertical scale shows a classical G/S deviation. It is linear with 2 dots on each side. Two dots correspond to plus (or minus) 0.175 ddm (150 microA) deviation. The index shows magenta G/S indication.
Until the glide beam is captured, the glide index is not shown (No Computed Data). When the index is against one stop, only one half of it is in view (the outer half index).
The G/S index and the scale flash permanently in case of G/S excessive deviation warning.
With a glide fault, the G/S index goes out of view and a red G/S failure warning message is shown in the middle of the scale.
F MMR - ILS Warning Display ** ON A/C NOT FOR ALL
LATERAL DEVIATION (item 4)
The horizontal scale shows a classical LOC deviation with 2 dots on each side. Two dots correspond to plus (or minus) 0.155 ddm (150 microA) deviation. The index shows magenta LOC indication.
Until the LOC is captured, the LOC index is not shown (No Computed Data). When the index is against one stop, only one half of it is shown.
The LOC index and the scale flash permanently in case of LOC excessive deviation warning.
With a LOC fault, its index goes out of view and a red LOC failure warning message is shown in the middle of the scale.
F MMR - ILS Data Display ** ON A/C NOT FOR ALL
F MMR - ILS Warning Display ** ON A/C NOT FOR ALL
(b) On NDs, in the ROSE ILS mode
In the ROSE ILS mode, the ND gives a display which is similar to that of a conventional Horizontal Situation Indicator (HSI): a heading dial orientated to the magnetic North turns and gives the actual magnetic heading of the aircraft in relation to the stable yellow lubber line.
The ND is always heading up:
A yellow aircraft model, at the center of the heading dial is stable and pointed up to the yellow lubber line.
Small white triangles are at an angle of 45 deg. on the circumference in relation to the lubber line.
They are stable and do not turn with the heading dial.
A green diamond-shaped symbol moves around the heading dial and gives the actual track of the aircraft.
The ND shows the indications given after, when available, in its right top corner (item 8):
  • The side of the displayed ILS receiver
  • The frequency
  • The course
  • The identification.
The ND shows the ILS APP message in its center top section (item 7) when the pilot has selected the ILS approach on the MCDU.
LATERAL DEVIATION (item 6)
A dagger-shaped pointer points to the selected ILS course. Its center part is the lateral deviation bar, which can move on a scale which is perpendicular to the pointer and has two dots on each side. The position of the bar on the scale gives the LOC deviation. The extreme dots correspond to plus or minus 0.155 ddm (plus or minus 150 microA). With LOC fault, a red LOC warning message comes into view in the middle of the LOC scale and the LOC deviation bar goes out of view.
VERTICAL DEVIATION (item 9)
A magenta lozenge gives the G/S deviation on a vertical scale at the right of the heading dial, if the aircraft is within the condition of reception of the ILS G/S signal.
The extreme dots of the vertical scale correspond to plus or minus 0.175 ddm (plus or minus 150 microA). With G/S fault, a red G/S warning message comes into view at the top of the scale and the index goes out of view.
(c) On NDs, in ARC and ROSE NAV modes
When you push the ILS pushbutton switch in ARC or ROSE NAV mode, the ND shows the symbols given after (item 11):
  • A magenta dagger-shaped pointer which points to the selected QFU
  • An arrow which indicates the lateral deviation of the aircraft related to the LOC axis.
(7) Warnings
F MMR - ILS Warning Display ** ON A/C NOT FOR ALL
The warnings related to the ILS are:
  • Local warning on the instruments that use the ILS information
  • MASTER CAUT lights on CAPT and F/O glareshield panels
  • Aural warning: Single Chime (SC)
  • Warning message shown on the upper display unit of the ECAM system.
B. GPS Function - Normal Operation
(1) General
To reduce initialization time, the MMR 1(2) receives position data, LAT/LONG (labels 310/311) from the ADIRU 1(2) and SET LAT, SET LONG (labels 041, 042) Universal Time Coordinated (UTC)/date from the FMGC 1(2) through the ADIRU 1(2).
Each MMR receives the GPS satellite RF signals from the active antenna to compute and provide the three ADIRUs with:
  • UTC, date
  • Position, altitude
  • Ground speed, track angle
  • N/S speed, E/W speed, vertical speed
  • Horizontal and vertical dilution of precision, figure of merit
  • Satellite position
  • Satellite measurement (pseudo-range, delta range, range rate, UTC measurement time)
  • GPS measurement status, sensor status
  • Real time and predictive integrity data.


Within each ADIRU, a hybridization function performs the following:
  • Monitoring of the MMR using GPS status word and ADIRU BITE
  • Generation of failure message for the ECAM display
  • Use of pseudo-range/delta range data to compute the GPS position
  • Use of inertial data to smooth GPS position/velocity
  • Use of a Kalman filter to estimate and minimize the errors
  • Use of IR data to improve the robustness of the MMR Radio and Audio Integrating Management System (RAIMS) algorithm
  • Transmission of GPS and GPIRS data to the FMGC for position fixing and display purposes.
(2) GPS primary navigation function principle in the FMGC
A navigation mode with the least error is chosen based upon the mixed IR position and the best GPIR or radio position available.
NOTE: The GPIRS position used by the FMGC to determine the aircraft position is computed in the GPIRS partition of the ADIRU (hybrid solution).
The Flight Management System (FMS) mode of navigation is selected according to the following hierarchy:
  • GPIR/Inertial
  • DME/DME/Inertial
  • DME/VHF Omnidirectional Range(VOR)/Inertial
  • Inertial only.
The GPIRS/INERTIAL mode is selected as long as the following conditions are satisfied:
  • GPIRS position is available and with an estimated accuracy consistent with the intended operation.
  • GPIRS integrity is available and compatible with the applicable phase of flight requirement.
    As long as the GPS/INERTIAL mode is active, no DME/DME or VOR/DME radio updation is allowed. However, LOC updation can apply to GPS/INERTIAL position.
    In this navigation mode, N IR/GPS indication is displayed on the POSITION MONITOR page with N being the number of IRs used to compute mixed IR position.
    The selected hybrid GPIRS position is displayed on the POSITION MONITOR page in place of the radio position.
    The mixed IR position and the IR deviations displayed on the POSITION MONITOR page do not change and are still computed using pure IR inputs.
    Aircraft position is generated by a series of filters which use inertial position, GPIRS position or radio position and aircraft velocity as input.
    A position bias is computed once every second through the position bias filter. This position bias is computed as the difference between the GPIRS position (or radio position) and the inertial position.
    The aircraft position is finally computed every 200 ms based on the corrected inertial position and the aircraft velocity using the aircraft position filter.
    The GPS/INERTIAL mode can be manually inhibited by pushing the line key adjacent to the DESELECT GPS indication on the SELECTED NAVAIDS page.
    F MMR - GPS SELECTED NAVAIDS Page on MCDU ** ON A/C NOT FOR ALL
    FMGC computed integrity:
    When the GPIRS position is available in the FMGC but the GPIRS integrity is not delivered by the ADIRS, the FMGC is capable of computing an equivalent integrity called alternate integrity monitoring, using IR data, during a limited period of time. The goal of this FMGC functionality is to improve the availability of the GPS primary function in the cockpit.
(3) Clock synchronization on GPS time
(a) If a GPS signal is present and valid when the power is on, the clock synchronizes on the GPS time using labels 150 and 260.
(b) If the signal is not present during synchronization, the clock displays dashes on all the digits.
(c) If the signal is present but not valid during synchronization, the clock indicates 00:00:00.
(d) If the signal becomes not valid after synchronization, the clock runs on its internal time base.
(4) Display of the GPS data on MCDU - GPS MONITOR
F GPS - GPS MONITOR Page on MCDU ** ON A/C NOT FOR ALL
The GPS data are displayed on the GPS MONITOR page of the MCDU.
To get the GPS MONITOR page, push the DATA key on the MCDU, then the line key adjacent to the GPS MONITOR indication.
The upper part is dedicated to GPS 1 data, the lower part to GPS 2 data.
The following data are displayed:
  • GPS position (lat/long)
  • True track
  • GPS altitude
  • Figure of merit (in meters)
  • Ground speed
  • Number of satellites tracked
  • Mode.
(5) Display of the GPS messages on ND
F MMR - GPS Data Displayed on the NDs ** ON A/C NOT FOR ALL
(a) Display of GPS PRIMARY LOST amber message
This message is displayed at the bottom of the image in all the ND modes (except engine standby modes) when the GPS primary is lost (this message cannot be cleared from the MCDU). In this case, the GPS is not used for navigation (accuracy and integrity for the intended operation can still be met by the use of alternate navigation means).
(b) Display of GPS PRIMARY white message
This message is displayed at the bottom of the image in all the ND modes (except engine standby modes) when the GPS becomes primary (this message can be cleared from the MCDU).
(c) Display of GPS APP green message
This approach message is displayed at the top of the image in all the ND modes (except engine standby modes) when a GPS approach is selected in the flight plan.
C. GPS Function - Warning
(1) GPS failure
The two Flight Warning Computers (FWC) monitor the GPSs with a status word that each GPS sends.
If a GPS failure occurs, the NAV GPS 1(2) FAULT message is shown in the lower part of the upper ECAM Display Unit (DU).
This message is shown in the conditions that follow:
  • The MASTER CAUT lights come on on the glareshield.
  • An aural warning is started: Single Chime (SC).
NOTE: The failure is also shown on the INOP SYSTEM page of the lower ECAM DU. The message that is shown is GPS 1(2).
(2) Loss of the GPS PRIMARY navigation
When there is a loss of the GPS PRIMARY navigation, the navigation function is unsatisfactory. It goes back to the standard navigation function with the Inertial Reference System (IRS) positions and the radio positions if available (in this condition, the properties of the Required Navigation Performance (RNP) continue to be available).
These warnings are started to show the loss of the GPS PRIMARY navigation:
  • The GPS PRIMARY LOST message is shown on the NDs (it is not possible to erase this message) and on the Multipurpose Control & Display Unit (MCDU) (it is possible to erase this message).
  • If there is a GPS non-precision approach, an aural alert is started (Triple Click).
(3) GPS/FMS position disagreement
When the GPS PRIMARY function is in operation, and one of the FM positions goes away from GPS positions 1 or 2 by more than:

A longitude threshold that is related to the latitude:
- 0.5' for latitudes below 55 degrees
- 0.9' for latitudes at or above 55 degrees, and below 70 degrees.

A latitude threshold of 0.5', with no relation to the latitude.

Then, the lower ECAM shows the NAV FM/GPS POS DISAGREE amber caution. The master caution light comes on and the single chime operates.
This amber caution is prevented during the takeoff phase.
Above a latitude of 70 degrees, a longitude difference does not start the alarm.
** ON A/C NOT FOR ALL
8. BITE Function
A. CFDIU Interface
(1) BITE description
The BITE facilitates maintenance on in-service aircraft. It detects and identifies a failure related to the MMR. The BITE of the MMR is connected to the CFDIU.
The BITE:
  • Transmits permanently MMR status and its identification message to the CFDIU
  • Memorizes the failures which occurred during the last 63 flight legs
  • Monitors data inputs from the various peripherals
  • Transmits to the CFDIU the result of the tests performed and self-tests
  • Can communicate with the CFDIU through the menus.
The BITE can operate in two modes:
  • The normal mode
  • The menu mode.
(a) Normal mode
During the normal mode, the BITE cyclically monitors the status of the MMR. It transmits its information to the CFDIU during the concerned flight.
In case of fault detection, the BITE stores the information in the fault memories.
These items of information are transmitted to the CFDIU by an ARINC 429 message with label 356.
(b) Menu mode
The menu mode can only be activated on ground.
This mode enables communication between the CFDIU and the MMR BITE by means of the MCDU.
F MMR - Maintenance Test Procedure ** ON A/C NOT FOR ALL
When you get access to the SYSTEM REPORT/TEST/NAV page, the ILS1 and ILS2 indications can be shown instead of the MMR1 and MMR2 indications. In this case, you must do the steps that follow:
  • Make sure that the engines are shut down
  • Open the CFDIU SUPPLY circuit breaker 2TW
  • Open the CFDIU BACK UP circuit breaker 8TW
  • Make sure that the MMR1 and MMR2 circuit breakers, 42RT1 and 42RT2, are closed
  • Wait for 30 seconds then close the CFDIU circuit breakers 2TW and 8TW
  • Wait for 180 seconds then get access to the SYSTEM REPORT/TEST/NAV page.
All the information displayed on the MCDU during the BITE Test configuration can be printed by the printer (Ref. AMM D/O 31-35-00-00).
The MMR menu mode is composed of:
  • LAST LEG REPORT
    F MMR - Last Leg Report ** ON A/C NOT FOR ALL
    This menu contains the fault messages (class 1 internal and external) detected during the last flight.
  • PREVIOUS LEGS REPORT
    F MMR - Previous Legs Report ** ON A/C NOT FOR ALL
    This report contains the fault messages related to the external or internal failures (class 1) recorded during the previous 63 flight legs.
  • LRU IDENTIFICATION
    F MMR - LRU Identification ** ON A/C NOT FOR ALL
    Allows to display the P/N, the serial number and the software number of the equipment.
  • GND SCANNING
    F MMR - Ground Scanning ** ON A/C NOT FOR ALL
    Based on the monitoring and fault analysis during flight, provides information of the failures detected during the use of this function.
  • TROUBLE SHOOTING DATA
    F MMR - Trouble Shooting Data ** ON A/C NOT FOR ALL
    Provides correlation parameters and snapshot data concerning the failure displayed in the LAST LEG REPORT and PREVIOUS LEGS REPORT.
  • CLASS 3 FAULTS
    F MMR - Last Leg Class 3 Faults ** ON A/C NOT FOR ALL
    Allows to display the class 3 faults recorded during the last flight leg.
  • GROUND REPORT
    F MMR - Ground Report ** ON A/C NOT FOR ALL
    Allows to present the class 1 or 3 internal failures detected on ground.
  • SYSTEM TEST
    F MMR - System Test ** ON A/C NOT FOR ALL
    F MMR - System Test ** ON A/C NOT FOR ALL
    Allows a check of the correct operation of the MMR.
(2) List of components
All the components are listed in Para. 2. Component Location.
(3) Reporting function
The tables below give the list of internal/external failures.
(a) Internal failures:
-----------------------------------------------------------------------------
I ATA I CLASS I MESSAGE I
I I (A/C) I I
I----------------------------------------------------------------------------
I 34-36-31 I 1 I MMRi (40RTi) I
I 34-36-11 I 1 I LOCALIZER ANTENNA (3RT)/COAX CABLE/MMRi(40RTi) I
I 34-36-18 I 1 I GLIDE ANTENNA (4RT)/COAX CABLE/MMRi (40RTi) I
I 34-36-16 I 1 I GPS ANTENNAi (43RTi)/COAX CABLE/MMRi(40RTi) I
I I I i = (1,2) I
-----------------------------------------------------------------------------

(b) External failures:
-----------------------------------------------------------------------------
I ATA I CLASS I MESSAGE I
I I (A/C) I I
-----------------------------------------------------------------------------
I 31-32-34 I 3 I CFDIU (1TW)/MMRi (40RTi) I
I 22-83-34 I 3 I FMGCi (1CAi)/RMPi (1RGi)/MMRi (40RTi) I
I 22-83-34 I 3 I FMGCj (1CAj) BUS ILS/MMRi (40RTi) I
I 22-83-34 I 3 I FMGC1 (1CA1) BUS GPS/MMRi (40RTi) I
I 22-83-34 I 3 I FMGC2 (1CA2) BUS GPS/MMRi (40RTi) I
I 34-12-34 I 3 I ADIRUk (1FPk)/MMRi (40RTi) I
I 32-31-71 I 3 I LGCIUi (5GAi)/FMGCi (1CAi)/MMRi (40RTi) I
I 31-62-34 I 1 I DMCi (1WTi)/MMRi (40RTi) I
I I I j,i = (1,2) or (2,1) I
I I I k = 1, 2 or 3 I
-----------------------------------------------------------------------------

(4) Interactive function
To gain access to the BITE, it is necessary to use one MCDU (Ref. AMM D/O 22-82-00-00).
F MMR - Last Leg Report ** ON A/C NOT FOR ALL
F MMR - LRU Identification ** ON A/C NOT FOR ALL
F MMR - Previous Legs Report ** ON A/C NOT FOR ALL
F MMR - Ground Scanning ** ON A/C NOT FOR ALL
F MMR - Trouble Shooting Data ** ON A/C NOT FOR ALL
F MMR - Last Leg Class 3 Faults ** ON A/C NOT FOR ALL
F MMR - Ground Report ** ON A/C NOT FOR ALL
F MMR - System Test ** ON A/C NOT FOR ALL
F MMR - System Test ** ON A/C NOT FOR ALL
All the information displayed on the MCDU during the BITE TEST configuration can be printed by the printer (Ref. AMM D/O 31-35-00-00).
B. BITE Implementation
(1) Activation of the receiver face test
The receiver face test can be activated by pushing the TEST pushbutton switch on the receiver face, if the test inhibit discrete is not active.
The sequence below is then generated on the receiver face.
Depending on the outcome of the receiver face test, one of the following results is displayed:
-----------------------------------------------------------------------------
I SEQUENCE I LRU STATUS I CONTROL I ANT FAIL I I TIME I
I NO. I LED (DS1) I FAIL LED I LED I DEFINITION I DEFINITION I
I I I (DS2) I (DS3) I I I
I---------------------------------------------------------------------------I
I 1 I Red I Red I Red I LED self- I 2 seconds I
I I I I I test I I
I---------------------------------------------------------------------------I
I 2 I Green I Red I Red I LED self- I 2 seconds I
I I I I I test I I
I---------------------------------------------------------------------------I
I 3 I Off I Off I Off I Unit self- I 2 seconds I
I I I I I test I minimum I
I---------------------------------------------------------------------------I
I 4 I Green I Off I Off I Unit passedI 30 seconds I
I I-------------------------------------------------I I
I I Red I I I Unit I I
I I I I I failed I I
I I-------------------------------------------------I I
I I I Red I I Control I I
I I I I Iinput failedI I
I I-------------------------------------------------I I
I I I I Red I Antenna I I
I I I I I failed I I
I---------------------------------------------------------------------------I
I 5 I Off I Off I Off I Test I Until next I
I I I I I complete I requested I
I I I I I I self-test I
-----------------------------------------------------------------------------

(2) Activation of the functional test
The functional test can be activated by pushing the line key adjacent to the TEST indication on the MMR maintenance sub-menu.
It is similar to the receiver face test except that the receiver face LEDs are not controlled to reflect the status of the unit, which is reported on the MCDU.
[Rev.10 from 2021] 2026.04.02 06:23:16 UTC
"WTRUIB" 2025