WEATHER RADAR SYSTEM - DESCRIPTION AND OPERATION

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1. General
The aircraft is equipped with an X-band weather radar system with Predictive Windshear capability. This system complies with the ARINC Characteristics 708A.
The weather radar system enables:

detection and localization of the atmospheric disturbances in the area defined by the antenna scanning: plus or minus 90 deg. of aircraft centerline and up to 320NM in front of the aircraft,
detection of turbulence areas caused by the presence of precipitations up to a distance of 40NM,
presentation of terrain mapping information by the combination of the orientation of the radar beam and of the receiver gain,
detection, if the Predictive Windshear System is operative, of a microburst windshear event in the area defined by the antenna scanning: plus or minus 60 deg.
presentation, if the Predictive Windshear System is operative, of windshear events within an area plus or minus 40 deg. of aircraft centerline and up to 5NM in front of the aircraft.
Autotilt capability (automatic tiltangle), the automatic tilt function is recommended for use in WX and TURB modes.

NOTE: A microburst is a cool shaft of air, like a cylinder, between 1000 and 3000 ft. When it encounters the ground (airflow velocity from 40 to 110 kts) the downward moving airflow is translated to a horizontal flow (from 80 to 220 kts), at the base of the air shaft. Two types of microburst exist, wet and dry.

Five color displays are used to show precipitations, turbulence and ground mapping to the crew.
The location of the windshear events, if the Predictive Windshear System is operative, is indicated by an icon (symbol consisting of alternating red and black arcs).
The aircraft is equipped with an X-band dual Collins WXR-2100 Multiscan Radar transceiver with Predictive Windshear System (PWS). This system is compatible with Electronic Instrument System 1 and 2 (EIS1 and EIS2) and complies with ARINC Characteristics 708A.
Multiscan is a radar function that displays all significant weather at all ranges, at all aircraft altitudes, and at all times on a display that is essentially clutter-free, without the need for pilots to input tilt or gain settings. Multiscan reduces pilot workload while enhancing weather detection capability.
The Multiscan function optimizes weather detection and minimizes ground clutter. This function determines the optimum tilt angle for the radar through monitoring of:

the aircraft altitude above the terrain (RA and ADR information).
the aircraft position (IR information).
the terrain conditions in the area (information located in an interval "Reference table").

Two antenna scans are performed, each scan is optimized for a particular region in front of the aircraft. The upper beam detects medium-range weather and the lower beam detects short and long-range weather by automatically adjusting tilt and gain. The information is then stored in a temporary database. When the captain or the first officer selects a range, the weather radar transceiver retrieves the appropriate portions of the desired information, merges the data and then eliminates ground clutter. The result is an optimized weather display and the flight crew selects the range scale required.

In the following text, the abbreviation WXR/PWS is used.
The WXR/PWS enables:
detection and localization of the atmospheric disturbances in the area defined by the antenna scanning: plus or minus 90 deg. of aircraft centerline and up to 320NM in front of the aircraft
detection of turbulence areas caused by the presence of precipitations up to a distance of 40NM
presentation of terrain mapping information by the combination of the orientation of the radar beam and of the receiver gain
detection of a microburst windshear event in the area defined by the antenna scanning: plus or minus 60 deg.
presentation of windshear events within an area plus or minus 30 deg. of aircraft centerline and up to 5NM in front of the aircraft.

Five color displays are used to show precipitations, turbulence and ground mapping to the crew.
The location of the windshear events is indicated by an icon (symbol consisting of alternating red and black arcs).

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2. Component Location

Weather Radar - Component Location ** ON A/C NOT FOR ALL

Weather Radar - Control and Indicating ** ON A/C NOT FOR ALL

The units of the weather radar system are located in the aircraft as follows:

FIN	FUNCTIONAL DESIGNATION	PANEL	ZONE	ATA REF
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1SQ1	XCVR-WEATHER RADAR, 1	109VU	121	34-41-33
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1SQ1	XCVR-WEATHER RADAR, 1	125AL	121	34-41-33
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3SQ	CTL UNIT-WEATHER RADAR	11VU	210	34-41-12
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7SQ	DRIVE-WR ANTENNA	110AL	110	34-41-11
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7SQ	DRIVE-WR ANTENNA		110	34-41-11
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9SQ	MTG TRAY-WR XCVR	109VU	121	34-41-37
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11SQ	ANTENNA-WEATHER RADAR	110AL	110	34-41-11
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11SQ	ANTENNA-WEATHER RADAR		110	34-41-11
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1SQ2	XCVR-WEATHER RADAR, 2	125AL	121	34-41-33

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3. System Description

Weather Radar Block Diagram - Data Acquisition ** ON A/C NOT FOR ALL

Weather Radar Block Diagram - Control and Display ** ON A/C NOT FOR ALL

The WR/PWS is composed of items closely associated with its operation, such as peripherals supplying parameters, EFIS display units or maintenance functions.

NOTE: The weather radar image is shown on the CAPT and F/O Navigation Displays (ND).
The NDs are connected to the three Display Management Computers (DMC) and to the CAPT and F/O EFIS control panels of the FCU.

NOTE: The three ADIRUs give data information to the weather radar system. These data ensure the radar antenna stabilization and the computations of the windshear function.

A. General
The weather radar system, which complies with ARINC Characteristics 708A, consists of:

a transceiver 1SQ1,
a control unit 3SQ,
an antenna drive 7SQ,
an antenna plate 11SQ,
a transceiver mounting tray 9SQ with a wave guide.

(1) Weather Radar Transceiver
The receiver-transmitter is the heart of the WR/PWS system, the additional necessary wiring and interfaces enable the weather radar transceiver to operate as a PWS (WR/PWS) and autotilt.
The receiver-transmitter ensures the following functions:

generation of the very short intense pulses of microwave energy via an X-band wave guide to the antenna, and the processing of their echoes (radio frequency signals) to obtain the desired information,
the receiver signal is formatted into 1600-bit ARINC 453 words and sent to the Display Management Computers (DMCs),
acquisition of data from Radio Altimeters (RA1 and RA2) and other specific interfaces,
windshear event detection and generation of the appropriate signal,
BITE function of the system.

(2) Weather Radar Control Unit
The control unit generates a 32-bit (label 270) serial control word which describes the selected operating modes (1/OFF/2, MAN/TILT/AUTO, WX, WX/TURB, MAP, W/S).
The WR/PWS receives one ARINC 429 bus coming from the control unit.
Moreover, the predictive windshear function can be de-activated if the PWS does not operate correctly.
The Autotilt control panel with MAN/TILT/AUTO switch included, it permits the selection of manual tilt or automatic tilt.

(3) WR Antenna Drive
The WR antenna drive is the interface of the transceiver to control and monitor the azimuth and elevation of the antenna.

(4) Weather Radar Antenna Plate
The antenna is used for transmitting and receiving radar radio frequency signals.

(5) Transceiver Mounting Tray with a Wave Guide
It allows to install the transceiver on the aircraft rack and connects the transceiver to the wave guide.
The wave guide switch is integral with the mounting tray. It ensures switching of the RF signal from the antenna to each transceiver. Moreover, control circuits recopy the wave guide switch position to avoid transmission on a closed wave guide.

(6) Weather Radar Control Unit
The control unit generates a 32-bit (label 270) serial control word which describes the selected operating modes (1/OFF/2, WX, WX + T, TURB, MAP, PWS, GCS, MULTISCAN, GAIN TILT).
The WR/PWS receives one ARINC 429 bus coming from the control unit.
Moreover, the predictive windshear function can be de-activated if the PWS does not operate correctly.

(7) WR Antenna Drive
The WXR/PWS has one antenna drive which is the interface of the transceiver to control and monitor the azimuth and elevation of the antenna.

(8) Weather Radar Antenna
The antenna is used for transmitting and receiving radar radio frequency signals.

(9) Transceiver Mounting Tray with a Wave Guide
It allows to install the transceiver on the aircraft rack and connects the transceiver to the wave guide.

(10) Weather Radar dual Control Unit
The control unit generates a 32-bit (label 270) serial control word which describes the selected operating modes (1/OFF/2, WX, WX + T, TURB, MAP, PWS, GCS, MULTISCAN, GAIN TILT).
The WR/PWS receives one ARINC 429 bus coming from the control unit.
Moreover, the predictive windshear function can be de-activated if the PWS does not operate correctly.

(11) WR Antenna Drive
The WXR/PWS has one dual antenna drive which is the interface of each transceiver to control and monitor the azimuth and elevation of the antenna.

(12) Weather Radar Antenna
The antenna is used for transmitting and receiving radar radio frequency signals.

(13) Transceiver Dual Mounting Tray with a Wave Guide
It allows to install each transceiver on the aircraft rack and connects the activated transceiver to the wave guide.

(14) General information

NOTE: The weather radar and windshear detection image (if the predictive windshear function is activated) is shown on the Captain and First Officer Navigation Displays (ND) and the windshear warning is shown on Captain and First Officer Primary Flight Displays (PFD) and on the upper ECAM DU. The NDs and PFDs are connected to the three Display Management Computers (DMC) and to the Captain and First Officer EFIS control sections of the FCU.

NOTE: If the Enhanced GPWS is operative, the WR image is replaced by the terrain image, on the Captain and First Officer NDs, during a terrain alert or a crew action.
More explanations are given in 34-48.

NOTE: The ADIRUs give to the weather radar system:

the altitude and the true airspeed (TAS) information (Ref. AMM D/O 34-13-00-00),
the attitude, ground speed, magnetic heading, true heading, E/W velocity, N/S velocity, track angle and drift angle (Ref. AMM D/O 34-14-00-00).
These data ensure the radar antenna stabilization and the corrections of the Doppler mode (turbulence).

B. Peripherals

(1) Digital serial data inputs
The transceiver receives digital serial data inputs from the following components:

(a) Radio Altimeter
The Radio Altimeter provides altitude information over two ARINC 429 bus inputs to the WR/PWS (label 164).
This data is used for automatic activation of the windshear function.
The second bus is for redundancy.

(b) Air Data Reference
Two ARINC 429 low-speed buses provide:

true airspeed data (label 210) used for velocity calculations
altitude data (label 203) used for sensitivity time control (STC) calculations
corrected altitude data (label 204) used only when label 203 is not available.

pitch (label 324) and roll (label 325) data for the stabilization and control of the antenna
east/west velocity (label 367) and north/south velocity (label 366) used for velocity calculations
ground speed (label 312) used for velocity calculations
track angle (label 317) used for velocity calculations
true heading (label 314)
Magnetic heading (label 320)
ADIRU align mode (label 270).

NOTE: The main air data and heading altitude data are provided by the Air Data/Inertial Reference System (ADIRS).

(d) Centralized Fault Display Interface Unit (CFDIU)
The WR/PWS communicates with the CFDIU low-speed ARINC 429 buses.

(e) EFIS Control Section
Two ARINC 429 buses provide the CAPT and F/O range selection (label 271).
The receiver/transmitter receives one bus from the CAPT EFIS control section and another one from the F/O EFIS control section.

(2) Digital serial data inputs
The transceiver receives digital serial data inputs from the following components:

(b) Air Data Reference
Two ARINC 429 low-speed buses provide:

true airspeed data (label 210) used for velocity calculations
altitude data (label 203) used for sensitivity time control (STC) calculations
corrected altitude data (label 206).

pitch (label 324) and roll (label 325) data for the stabilization and control of the antenna
east/west velocity (label 367) and north/south velocity (label 366) used for velocity calculations
ground speed (label 312) used for velocity calculations and qualifiers C1, C2
track angle (label 317) used for velocity calculations
true heading (label 314)
Magnetic heading (label 320)
Body longitudinal acceleration (label 331) used for qualifiers D1, D2.

NOTE: The main air data and heading altitude data are provided by the Air Data/Inertial Reference System (ADIRS).

(d) Centralized Fault Display Interface Unit (CFDIU)
The WR/PWS communicates with the CFDIU low-speed ARINC 429 buses.

(f) One ARINC 429 high-speed bus (Hazard) provides radar data to be recorded on the Flight Data Interface and Management Unit (FDIMU).

(g) One ARINC 429 high-speed bus (Hazard) provides radar data to the Enhanced Ground Proximity Warning System (EGPWS).

(3) Discrete inputs
The transceiver receives the following discrete inputs:

(a) Ground/flight signal and landing gear extended signal.
These signals are provided by the Landing Gear Control and Interface Unit (LGCIU).

Ground/flight signal is used to determine the identifying flight phase for BITE
Landing gear extended signal is used to determine transition from landing mode to takeoff mode to identify a GO AROUND condition. In this case the appropriate aural message is generated.

(b) Qualifiers A and B signals (if predictive windshear function is activated)
Two types of qualifier inputs are used to control automatic activation of the windshear function.

qualifiers A: two qualifiers A inputs are used. These input signals are provided by the ATC/TCAS control unit.
The qualifier A1 signal coming from J1 ATC/TCAS control unit is connected to the WR/PWS transceiver.
The qualifier A2 signal coming from J2 ATC/TCAS control unit is connected to the WR/PWS transceiver.
The qualifier A2 is for redundancy.
This qualifier A is considered valid when one ATC transponder is selected in operative mode on the ATC/TCAS control unit.
qualifiers B: two qualifiers B inputs are also used. These input signals are provided by the engine oil pressure sensors indicating when there is normal operating pressure.
The qualifier B1 is connected to engine 1 and the qualifier B2 is connected to engine 2.
Qualifiers B1 and B2 are connected to the transceiver.
This qualifier B is considered valid when the engine is running (high oil pressure).

To automatically activate the windshear function, one of the qualifiers A and one of the qualifiers B have to be valid.

(c) Windshear function enable signal (if predictive windshear function is activated)
This discrete input provided by the weather radar control unit through the windshear AUTO/OFF switch activates the windshear function. This discrete signal is also transmitted to the DMCs which use it for the logic of windshear messages displayed.

(d) Windshear BITE enable signal (if predictive windshear function is activated)
This discrete input allows the WR/PWS to manage the BITE windshear failures sent to the CFDIU.

(4) Discrete inputs
Each transceiver receives the following discrete inputs:

(a) Ground/flight signal and landing gear extended signal. These signals are provided by the Landing Gear Control and Interface Unit (LGCIU).

Ground/flight signal is used to determine the identifying flight phase for BITE
Landing gear extended signal is used to determine transition from landing mode to takeoff mode to identify a GO AROUND condition. In this case the appropriate aural message is generated.

(b) Qualifiers B, C, D signals (new qualifier logic/qualifier A: ATC is no more used).
Two types of qualifier inputs are used to control automatic activation of the windshear function (B and C or B and D).

qualifiers B: two qualifiers B inputs are used. These input signals are provided by the engine oil pressure sensors indicating when there is normal operating pressure.
The qualifier B1 is connected to engine 1 and the qualifier B2 is connected to engine 2.
The qualifier B2 is for redundancy.
Qualifiers B1 and B2 are connected to transceivers 1 and 2.
Qualifiers C: two qualifiers C inputs are used.
Qualifier C1: ground speed (label 312 provided by IR bus from IR1) (valid when GS > 30Kts).(Ref. asterisk below)
Qualifier C2: ground speed (label 312 provided by IR bus from IR3) (valid when GS > 30Kts).
Qualifiers D: two qualifiers D inputs are used.
Qualifier D1: body longitudinal acceleration (label 331 provided by IR bus from IR1) (valid when Nx > 0.07g for at least 0.5 seconds).(Ref. asterisk below)
Qualifier D2: body longitudinal acceleration (label 331 provided by IR bus from IR3) (valid when Nx > 0.07g for at least 0.5 seconds).
(*) For the second transceiver, C1 and D1 information is provided by IR2.

To automatically activate the windshear function, one of the qualifiers B and one of the qualifiers C or D have to be valid.

(c) Windshear function enable signal
This discrete input provided by the weather radar control unit through switch AUTO/OFF enables the windshear function. This discrete signal is also transmitted to the DMCs which use it for the logic of windshear messages displayed.

(d) Windshear BITE enable signal
This discrete input allows the WXR/PWS to manage the BITE windshear failures sent to the CFDIU.

(5) Outputs
The transceiver provides the following outputs:

(a) Displays
The WR/PWS is connected to the DMCs by an ARINC 453 bus to transmit the weather radar data and windshear data (if predictive windshear function is activated) on the data word of label 055.
All the weather and windshear data received by the DMCs are processed to display weather radar image and windshear events by the Electronic Instrument System (EIS).

1 The Navigation Display (ND) it provides the following indications:

weather radar image
windshear events location for advisory, caution or warning alert
windshear failures.

2 The Primary Flight Display (PFD) it provides all visual alerts for caution or warning alert.

NOTE: The Flight Warning Computers (FWC) and the FDIU receive WR/PWS data through the DMCs. These data are used by the FWCs to display windshear function failure and windshear function de-activation.
The FDIU records the windshear alert and failure.

(b) Centralized Fault Display System (CFDS)
The WR/PWS is connected to the CFDS to transmit the following words:

label 354: LRU identification P/N and S/N (coded in ISO5)
label 356: fault message (coded in ISO5)
label 377: equipment identification.

(c) Audio Mixing Box (if predictive windshear function is activated)
An analog audio output allows to transmit the aural alert windshear (synthetic voice message) to an audio mixing box connected to loud speakers.

(d) Enhanced Ground Proximity Warning System (Enhanced GPWS) (optional)
The Enhanced GPWS receives WR/PWS alerts from WXR1 Hazard bus and WXR2 Hazard bus (when the second transceiver is installed) to determine the alert priorities.
Predictive Windshear alerts override a terrain display and revert to the WR display with the corresponding windshear data.
The alert priorities between the WR/PWS and the Enhanced GPWS have been defined as follows:
1- WR/PWS Warning,
2- WR/PWS Caution,
3- Terrain Warning,
4- Terrain Caution,
5- WR/PWS advisory (no audio),
6- Terrain background (no audio).

(e) Flight Data Interface and Management Unit (FDIMU)
One ARINC 429 high speed bus (hazard) provides radar data to be recorded on FDIMU.

(f) Windshear function enable signal
This discrete input provided by the radar control box through AUTO/OFF switch enables the windshear function. This discrete signal is also transmitted to the DMCs which use it for the logic of windshear messages displayed.

(6) Audio Inhibit Discrete Signals (if predictive windshear function is activated)
These discretes are used to indicate whether the aural alert output has to be active or not:

predictive windshear aural alerts (audio inhibit discrete input) are inhibited by the Reactive Windshear System and stall warning.
predictive windshear audio inhibit discrete output is used to inhibit other aural alerts generated by systems such as: Traffic Alert and Collision Avoidance System (TCAS) or Ground Proximity Warning System (GPWS) or other FWC warnings.
This inhibition occurs each time there is a PWS aural alert.

(7) Pin Programming (if predictive windshear function is activated)

audio level program pins set the audio output level of the synthetic voice for windshear aural alert.
SDI (Source Destination Identification Encoder) program pins encode the location of the WR/PWS unit on the aircraft when two transceivers are installed.
qualifier polarity program pins: for both qualifiers, this pin program indicates the validity of the signal.
CFDIU interface program pins: when the second WR/PWS is installed on the aircraft, this program pin is activated. The WR/PWS can communicate with the CFDIU.
caution alert audio program: two program pins are provided to select the type of windshear caution aural alert.
The MONITOR RADAR DISPLAY synthetic voice is generated instead of the chime.
windshear function enable program pins is used to activate the windshear function.
windshear function bite enable signal allows to send to CFDIU failure related to the predictive windshear function.

C. General Technical Characteristics
The WR/PWS system is mainly used to detect and localize various types of atmospheric disturbances and windshear events in the area scanned by the antenna. The system shows the disturbance intensity through the use of colors which vary with the atmospheric precipitation rate.
The disturbances are shown to the crew members on the NDs with different colors:

black, green, yellow, red to quantify the precipitation rates
magenta to represent the turbulence areas up to 40 NM.

The system can show the location of the windshear events via the NDs:
alternating black and red arcs depict the windshear event.
As the minimum display range is 10 NM, two yellow radials appear at the edges and start beyond the windshear (W/S) event.

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4. Power Supply
Energization of the system is through a 115VAC/400 Hz bus:

1XP via the busbar 101 XP-C for transceiver 1

Energization of the weather radar control unit and of the WR antenna drive is through the transceiver.
Consumption of the transceiver is 125 W nominal.
Energization of the system is through a 115VAC/400 Hz bus:

1XP via the sub-busbar 101 XP-C for transceiver 1.

Energization of the weather radar control unit and of the WR antenna drive is through the transceiver.
Consumption of the transceiver is 145 W maximum.
The system is supplied through this circuit breaker:

A. Circuit Breakers Table

PANEL	DESIGNATION	FIN	LOCATION
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121VU	COM NAV/RADAR/1	5SQ1	K13
121VU	COM NAV/RADAR/2	5SQ2	K14

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5. Interface

A. Digital Interface Special for Weather Radar
The weather radar data are transmitted via ARINC 429 and 453 buses in compliance with ARINC 708A.
The table below contains all the output parameters in the digital form.

-------------------------------------------------------------------------------

| PARAMETER LIST PARAMETER CHARACTERISTICS (NUMERIC) |

-------------------------------------------------------------------------------

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! 055 ! WXR DATA ! ! ! !1600!7.82! DIS! ! !

! ! ! ! ! ! ! ! ! ! !

!--------------!----------!------------!----!----!----!----!----!-----!-------!

! 270 ! CONTROL ! ! ! ! 32 !100 ! DIS! ! !

! ! WORD 1 ! ! ! ! ! ! ! ! !

!--------------!----------!------------!----!----!----!----!----!-----!-------!

! 271 ! CONTROL ! ! ! ! 32 !100 ! DIS! ! !

! ! WORD 2 ! ! ! ! ! ! ! ! !

!--------------!----------!------------!----!----!----!----!----!-----!-------!

! 356 ! Mainte- ! ! ! ! !100 !ISO5! ! !

! ! nance ! ! ! ! ! ! ! ! !

! ! message ! ! ! ! ! ! ! ! !

! ! word ! ! ! ! ! ! ! ! !

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(1) Control Words (Labels 270 and 271)
The control words are transmitted on the control buses which connect the weather radar control unit to the transceiver.
The control word 1 (label 270) provides the following data:

gain,
tilt angle,
selected mode,
stabilization (on/off),
scan angle (normal/reduced),
anticlutter (on/off) (optional)
split function (Capt/Both/F/O) (optional)

The control word 2 (label 271) provides the following data:

range,
anticlutter (on/off) (optional),
WR selected on the EFIS control section (master/slave).

(2) Data Word (Label 055)
The signal transmitted on the data bus line which connects the WR/PWS to the Display Management Computers (DMC) complies with data word format (label 055) as defined by the ARINC Specification 708A (Appendix 15.2).
The data bus line transmits 190 data words per second; each word is made up of 1600 bits sent on 1 Megabit/s frequency (ARINC Specification 453) as per MANCHESTER II BI PHASE 2 format.

Weather Radar - Manchester II Biphase Format ** ON A/C NOT FOR ALL

Data word message includes mainly the radar return intensity and windshear data.

-----------------------------------------------------------------------------

! BITS ! FUNCTION !

!----------!----------------------------------------------------------------!

! 1-8 ! Label 00101101 : 055 !

! 9-10 ! Control Accept !

! 11 ! Spare !

! 12 ! Windshear Caution !

! 13 ! Windshear Warning !

! 14 ! Turbulence Alert !

! 15 ! Tilt selection !

! 16 ! Anticlutter !

! 17 ! Sector Scan !

! 18 ! Stabilization Limits !

! 19 ! V2 on board !

! 20 ! Display Fault (not used) !

! 21 ! Calibration or Air Data Input !

! 22 ! Attitude Input !

! 23 ! Control or Heading Input !

! 24 ! Antenna !

! 25 ! R/T or Radio Altimeter !

! 26 ! Stabilization !

! 27-29 ! Mode !

! 30-36 ! Tilt Angle !

! 37-42 ! Gain !

! 43-48 ! Range !

! 49 ! Windshear External Input Fault !

! 50-51 ! Data Accept !

! 52-63 ! Scan Angle !

! 64 ! Windshear Failure !

! 65-1600 ! Range Bin Data !

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The WR/PWS uses the "Space address usage" technology defined by the ARINC specification 708A for transmission of information on data bus lines. This is achieved by two different data bus lines, each associated with a control bus line from an EFIS control section of the FCU.
Data BUS 1 transmits always data associated to the range selected on EFIS/CAPT (side 1).
Data BUS 2 transmits always data associated to the range selected on EFIS/F/O (side 2).
The control and data bits of word label 055 are valid at any moment on both DATA BUSES, even if the range selected on sides 1 and 2 of FCU are different.

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6. Component Description

A. Weather Radar Transceiver FIN: 1-SQ-1 FIN: 1-SQ-2

Weather radar - Architecture ** ON A/C NOT FOR ALL

Weather Radar Transceiver - Component Description ** ON A/C NOT FOR ALL

The weather radar transceiver with PWS is a lightweight airborne unit.
The transmitter section consists of a crystal-controlled reference oscillator, driver stage and a power amplifier output stage.
Pulse widths are either 1.5 microseconds (used to produce the calculated windshear hazard presentation), 6 microseconds or 18 microseconds.
Echoes from both the 6 and 18-microsecond pulses are processed to produce targets between 20 and 40 NM. The 6-microsecond pulses are also used for turbulence detection.
The master processor is the host control computer for the weather radar system with PWS. It also produces the timing and control signals that control the operations of the modulator/transmitter and receiver, and the weather, turbulence and windshear digital signal processor circuits.
The master processor decodes the ARINC 429 mode information from the control unit and selected range.
During the transmit period, the radio frequency front end, through its waveguide element, sends the pulse-modulated X-band radar signal to the radar antenna.
During the receive period, the radio frequency front end receives signals through the waveguide element and through a filter to the preamplifier. The received signal is mixed to produce the 212 MHz signal which is sent to the receiver.
The receiver operates with digital slow AGC and provides high-gain narrow-band amplification. It converts the 212 MHz first i-f signal to a 5 MHz third i-f signal.
The receiver 5MHz i-f signal output is applied to an analog-to-digital (A/D) converter at the input to the digital signal processor (DSP) subsystem.
The analog-to-digital converter digitizes the detected video signal from the receiver.
Three separate video processors process the digitized video signal to accommodate three radar displays with independent range selection. The video processor averages the digitized video data within each range bin.
A range bin is defined as the range interval over which the radar data are derived. This is determined by the division of the selected range into 512 equal increments.
The range averaged data are stored and filtered at each transmission by the video processors.
The ARINC 453 interface circuits format the outputs of the video processors and send them to the DMCs and the EFIS.
The antenna stabilization circuit is internal to the weather radar transceiver with PWS and is built around a 16-bit microprocessor. It is controlled by a servo loop. Five angles are provided to the microprocessor to solve the stabilization equation (line of sight):

aircraft pitch and roll angles
selected antenna tilt angle
antenna elevation angle
antenna azimuth angle.

The aircraft pitch and roll angles are transmitted by the Air Data/Inertial Reference Units (ADIRUs) in the form of ARINC 429 messages.
Only the antenna azimuth control is an open loop and the microprocessor generates the antenna feedback signal. The antenna reaches plus or minus 90 deg., on either side of the aircraft centerline.
The microprocessor generates the control signals of the elevation and azimuth drive motors of the antenna; the corresponding angular positions are recopied by synchros located in the antenna and processed by the microprocessor.
The output data of the linear amplifier is processed for comparison of the detected signals with a threshold said of medium turbulence.
Furthermore corrections are made with respect to the selected tilt angle and to the ground speed transmitted by the attitude bus.
The control and monitoring circuit is used for the control of the transceiver, the monitoring circuit of the video processors and the ARINC 429 interface circuits.
In addition, the control circuit determines the operating mode of the weather radar, the system gain, the tilt angle and the range selection for the video processor.
During the program loop, selected inputs are checked or compared to determine the operational status of the weather radar system with PWS. The results of these checks or comparisons are used to display fault warning messages on the display units and to the Liquid Crystal Display of the front panel of the transceiver.
The display contains a sequence of software controlled pushbutton switches that result in different functions when pressed. Once the TEST pushbutton switch is pressed, the display shows TEST IN PROGRESS. At the end of the test, the display shows RADAR OK, INPUT OK if no faults were detected in either the radar or input connections.
The maintenance circuit with processor ensures formatting of signals and the interface with the CFDS. The processor is continuously supplied to answer the interrogations of the CFDS. In addition, it has access to a non volatile fault memory to report all failure conditions. The monitor processor also enables to activate the system complete test from the CFDS.
The different flight phases are generated from a flight/ground discrete provided by the Landing Gear Control and Interface Unit (LGCIU). This discrete enables the CFDS flight phases to be consolidated.

Weather radar - Architecture ** ON A/C NOT FOR ALL

Weather Radar Transceiver - Component Description ** ON A/C NOT FOR ALL

The weather radar transceiver with PWS is a completely solid-state airborne unit.
It contains:

(1) A power amplifier
A single 777.77 MHz multiplier drive signal is developed by the power amplifier. The power amplification of the transmit section is accomplished by splitting the power amplifier drive before recombining the signals into a single multiplier drive signal.

(2) A power multiplier
The power multiplier produces the 9333.24 MHz transmitter output signal from the single multiplier drive signal (from the power amplifier).
The multiplier drive signal is multiplied by 3 to produce a 2333.31 MHz signal. The 2333.31 MHz signal is their quadrupled to produce the 9333.24 MHz transmitter output signal.

(3) A duplexer/monitor
The transmitter output is coupled through a duplexer/monitor to the waveguide antenna feed through a 4-port circulator. Incorporated in the duplexer operation are monitor circuits to monitor the output power level and develop a frequency loop error signal for the correction of frequency chirp.
The monitor circuit also accepts a test signal which causes a portion of the reference signal to be injected into the receiver for test calibration. The 4-port circulator also couples the RF return from the waveguide antenna feed through the preamplifier to the receiver portion of the transceiver.

(4) A preamplifier
The preamplifier assembly perform the waveguide limiter functions (protects the mixer diodes from all high power pulses), contains a noise diode circuit and contains a 2-stage RF amplifier which provides +18dB of RF gain.

(5) A mixer
The mixer circuit processes the detected RF return signal by mixing it with the First local oscillator signal and amplifying the resultant Intermediate Frequency (IF) signal in the First IF amplifier.
The first IF amplifier provides 25dB amplification before the First IF signal is applied to the second IF amplifier.

(6) A second IF amplifier
The second IF amplifier completes the receiver amplification of the RF return signal. The output from the first IF is converted to the 13.8888 MHz second IF signal by mixing it with the 152.77 MHz second local oscillator signal. The second IF signal is double-buffered and applied to a synchronous detector. The third local oscillator signal is phase-split to obtain one signal in phase with the transmitter frequency and one signal phase shifted by 90 deg.

(7) A sampler
The sampler commands and controls the receive and transmit functions within the receiver-transmitter. A digital signal processor is used to control transmitter timing and receiver normalizer.

(8) A digital signal processsor
The digital signal processor circuit card performs the weather processing, clutter identification, clutter filtering, velocity extraction and editing, hazard computation and hazard recognition algorithms. Command and control information is passed from the digital signal processor to the sampler through a dual port RAM.

(9) A central processing unit
Control of internal functions, antenna servo controls, monitoring of system operation and formatting the processed data is accomplished by the central processing unit. It uses a microprocessor and a stored program to execute the following major routines that control the transceiver and system operations:

attitude routine, providing pitch and roll parameters for the stabilization routine
stabilization routine, providing elevation position to the elevation maintenance routine
scan maintenance routine, providing antenna scan drive
elevation maintenance routine, providing antenna elevation drive control bus manager routine, determining correct control configuration
problem control monitor routine, programming the internal data collection parameters of the transceiver
data bus formatter routine, processing and assembling the control message of the serial data word sent to the EFIS.

(10) An input/output unit
All interface functions between the microprocessor of the central processing unit and the rest of the transceiver and units in the system are provided by the input/output unit. Control word buses, digital and analog attitude buses, radio altitude inputs and discrete buses are all connected to the multiplexer and shift register of the input/output unit. In addition, the input/output unit contains speech circuits for windshear hazard annunciation, the synchro-to-digital conversion circuits, discrete warning annunciation outputs, aural warning outputs and remote turn-on circuits.

(11) A BITE/monitor
The BITE/monitor provides the BITE power supply voltages to BITE functions and circuits, a power monitor for the detected transmitter output and an interconnect for various signals used throughout the transceiver.

(12) RF replacement modules
The transmitter, preamplifier and X54 modules of the RF portion of the RTA-4A/4B radar transmitter/receiver have been redesigned. Each of the three RF modules has been designed for complete compatibility and interchangeability with the original modules. As such, functional tests of the radar with the new modules are identical to those used for the original design.

(13) X54 frequency multiplier module
The X54 frequency multiplier module replaces the existing X9, X6 and circulator assemblies in the RDR-4A and RDR-4B transmitter. This module multiplies and amplifies a 173 MHz (nominal) signal input from the frequency source board. The RF outputs a 1557 MHz signal used as the input to the receiver and a 9342 MHz signal for the transmitter.
The X54 module includes a VHF amplifier stage, a X9 multiplier stage, an L-band amplifier, a transmit/receive switch, a X6 multiplier, a modulated X-band amplifier, an isolator and a BITE circuit. Additionally, there is a bias regulation, control, modulation and temperature compensation circuitry to obtain the necessary control signals and bias voltages.

(14) Preamplifier module
The RF preamplifier module includes a solid-state limiter, a low noise amplifier, an image-reject filter, a diode noise generator, a low-power X6 frequency multiplier, and the first mixer stage. The RF preamplifier receives the 9346 MHz (nominal) radar-return signals from the antenna/circulator and produces low-noise, high-gain preamplification and image-rejection filtering.
The limiter is an active/passive pin-diode limiter. During transmission, it reduces the level of transmitter RF reaching the preamplifier circuitry. During reception, the limiter protects the preamplifier against the effects of transmissions from other nearby transmitters.

(15) Transmitter module
The new RDR-4A/4B transmitter is based on standard RF amplifier technology using RF Field Effect Transistors (FET) distributed through four power-combined amplifier modules. The transistor amplifier does not produce any microwave signals of its own, but rather amplifies the microwave power provided by the older X6 and X9 multiplier module or the new X54 module. The failure of one of the four amplifier modules will not cause the overall failure of the transmitter, just a small reduction in output power level.
The new transmitter has been designed to be a direct replacement for the existing IMPATT transmitter. It mounts using the same mounting points as the older IMPATT transmitter and uses the same power and logic cable connection as the older transmitter.
This new transmitter provides roughly the same output power as the older transmitter and exhibits lower levels of electromagnetic interference (EMI) and lower levels of distortion (harmonics and spurious output) than the present transmitter.

B. Weather Radar System
The system has five modes of operation:

Weather
Weather with Turbulence detection
Ground Mapping
Autotilt
Windshear.
The autotilt function is available on P/N:066-50008-0409.

(1) Weather Radar
The weather radar system RDR-4B provides storm detection up to a distance of approximately 320NM under ARINC 708A defined penetration environment.

Cloud formations having less moisture content than required to reflect a minimum discernible echo signal do not appear on the ND.

The color presentation gives an immediate indication of the location of severe storm areas. These areas might contain air turbulence which should be avoided.

A microprocessor processes the weather returns to indentify areas of precipitation with moderate to high turbulence. This capability enhances the rainfall intensity information provided by the basic radar, which to enables pilots to avoid threatening weather. The turbulence detection circuitry uses the Doppler phenomenon, which causes an apparent echo between the radar and the target. The Doppler processor measures the return velocity variance to indicate the turbulence present in the weather.

(2) Weather with Turbulence Detection
The Doppler processor for the RDR-4B system processes the weather returns to identify areas of precipitation with moderate to high turbulence. This capability enhances the rainfall intensity information provided by the basic radar, which enables pilots to avoid threatening weather. The turbulence detection circuitry uses the Doppler phenomenon, which causes an apparent echo-signal frequency shift due to relative motion between the radar and the target. The Doppler processor measures return velocity variance to indicate the turbulence present in the weather.

(3) Ground Mapping
Ground mapping with the RDR-4B radar system provides a plan picture of prominent landmarks and terrain features such as cities, shore lines, mountains, islands, bay, bridges, etc. These terrain features are shown on the ND in slant range and azimuth bearing with respect to the heading of the aircraft.

Of prime importance for the pilot is the extended range of vision and the ability to see this terrain map during darkness and overcast conditions, when visibility is restricted. The display in ground mapping look like a pilotage chart and can be easily interpreted. Cities, open ground, and bodies of water provide progressively less intense reflections. It should be noted that calm water reflects very little signal back to the antenna. However, very rough water provides a signal return of considerable strength.

The planar antenna array provides only pencil beam. Terrain mapping for short ranges (less than 75NM) requires tilt adjustment to cover the scan area.

(4) Autotilt
The weather radar RDR-4B can operate in autotilt mode (automatic tilt angle): the use of the automatic tilt function is recommended in WX and TURB modes.

The autotilt function uses the terrain altitude information of the Enhanced GPWS. the Enhanced Ground Proximity Warning System (E-GPWS). Based on the aircraft altitude above the terrain and on terrain conditions in the area, the Enhanced GPWS determines the optimum tilt angle for the radar. This automatic tilt angle setting results in minimum ground clutter on the display while maintaining an optimum weather detection capability. One exception is the autotilt MAP mode, where the radar beam is intentionally aimed at the ground as a function of range.

NOTE: Manual tilt should be used when analyzing terrain and storm characteristics.

The autotilt function is integrated in the existing windshear submodes. On preparation for takeoff through 2300 feet, the weather scans alternate with the windshear scans. This occurs on approach, as well, below 2300 feet. The autotilt function controls the tilt only during weather scans. The windshear scan algorithm does not change with the autotilt functionality.

NOTE: When range settings are different (one display at a range of more than 80NM and the other display at a range of less than or equal to 80NM) the weather radar scans alternately to cover the different range settings.

The autotilt functionality is optimized for range settings less than or equal to 80NM (short range) and range settings more than 80NM (long range). If above 2300 feet AGL and if all displays are set to the same setting (either all short range or all long range), the weather display is updated in both directions clockwise (CW) and counterclockwise (CCW). If above 2300 feet AGL and if at least one display is on short range while the others are on long range, then the weather display is updated on alternate scans to account for the different autotilt settings required. Below 2300 feet AGL, the autotilt scans are based on short range tilt setting. There is no long range/short range alternate scanning in the windshear active region.

Weather Radar - Automatic Tilt Antenna Scan Pattern ** ON A/C NOT FOR ALL

The antenna scan is divided into five sectors/areas. The tilt angle displayed for each sector is calculated based on aircraft altitude, terrain height and range selection.

(5) Antenna Scan Pattern

Weather Radar - Manual Tilt/Automatic Tilt ** ON A/C NOT FOR ALL

Figure 009 shows the benefits of autotilt with manual tilt control: there can be over scan where the weather cells and the terrain are below the antenna beam and the display is blank, or under scan where the antenna scan is basically hitting the ground below the weather cells and the display contains only ground clutter. The integration of Enhanced GPWS and radar functionality (autotilt) provides a layer of protection against these extremes.

(6) Autotilt Selection
Automatic tilt is selected by setting the TILT (AUTO/MAN) switch to AUTO on the weather radar control unit (CON-4A/4B).
Switch to AUTO: Tilt setting for weather scans is automatic.
Switch to MAN: Tilt is controlled with the manual tilt control knob.

Pitch and roll information from the aircraft vertical gyros, tilt information from the manually set tilt control, azimuth angle information from the azimuth (scan) synchro transmitter, and elevation angle information from the elevation synchro transmitter, are processed by the stabilization microprocessor drive motor. The elevation drive motor repositions the antenna to maintain line-of-sight.

Also supplied by the R-T unit is the azimuth motor drive signal which drives the antenna through the oscillating 180 degrees of azimuth (scan).

NOTE: Manual TILT should be used when analyzing terain and when analyzing storm characteristics. selection of either manual or autotilt is done with selected control units. The RF signal (transmitted or received) is conveyed by a wave guide between the antenna and the transceiver. Energization of the antenna is 115VAC 400HZ throught the selected transceiver.

(7) Dual System Antennas

Weather Radar - Single Motor Antenna Drive ** ON A/C NOT FOR ALL

To provide for dual system operation, the antenna contains redundant position synchro transmitters. Synchro transmitters B6 and B1 and associated with system 1; synchro transmitters B4 and B3 are associated with system 2. These redundant servo loops are interconnected through redundant antenna connectors (J3001, system 1) and (J3002, system 2) to the RDR-4B system. All circuitry commmon to a dual system is configured in such a way that either a Receiver-Transmitter unit, indicator, or synchro transmitter failure will not render the RDR-4B system inoperative.
A system tranfert switch on the CON-4B control panel applies power to the selected system and applies a switching voltage to a waveguide switch mounted on the R-T mounting base.

The waveguide switch transfert the antenna rf feed (waveguide) to the selected R-T unit. On the figure, sytem 1 is selected for operation by placing the System Transfert Switch (STS) on the CON-4B in the SYS 1 position. This energizes and initiates the switching necessary for system 1 operation.
For either dual or single system operation, motor B5 drives the antenna in azimuth movement and motor B2 drives the antenna in elevation position.

NOTE: The single system antenna is designed for use with one R-T unit. The function and components of the single system antenna are the same as the dual system antenna except that single synchros are used in lieu of redundant synchros and only on connector (J3001) is wired to electrical components in the antenna.

C. Weather Radar Antenna

Weather Radar - Dual Antenna Drive ** ON A/C NOT FOR ALL

The weather radar antenna is controlled in azimuth and elevation by the transceiver. The antenna movements are ensured by 2 DC motors and the angular positions are recopied by 2 or 4 synchros (2 for a single antenna and 4 for a dual antenna). The RF signal (transmitted or received) is conveyed by a wave guide between the antenna and the transceiver.
Energization of the antenna is 115VAC/400 Hz through the transceiver.

Weather Radar - Antenna ** ON A/C NOT FOR ALL

The weather radar antenna is controlled in azimuth and elevation by the transceiver CPU. The binary control data are decoded and activate the antenna scan and elevation steeper motors through corresponding power circuits. The indication of these positions is sent to the CPU for comparison. The RF signal (transmitted or received) is conveyed by a wave guide between the antenna and the transceiver.
Energization of the antenna is 115VAC/400 Hz through the transceiver.

D. Weather Radar Control Unit
The gain and tilt potentiometric data are digitized by an 8-bit analog-to-digital converter.
Moreover the different positions of the mode selector switch and the potentiometric data are formatted according to the ARINC 429 control word.
Part of weather radar controls is grouped on the control unit (TILT control, system GAIN control, MODE selection control, MULTISCAN MAN/AUTO mode).
These data are digitized and monitored by a CPU to generate a control word which is sent to the transceiver through a control bus line.

E. Weather Radar

(1) Wave Guide.
A wave guide assembly ensures the RF connection between the WR antenna drive and the WR transceiver mounting tray (connected to the wave guide switch).
The wave guide assembly is made up of rigid and flexible parts which have a standard rectangular section (1 in. x 0.5 in.).

(2) Wave Guide Switch.
The wave guide switch is integral with the mounting tray. It ensures switching of the RF signal from the antenna to the transceiver. Moreover control circuits recopy the wave guide switch position to avoid transmission on a closed wave guide.

** ON A/C NOT FOR ALL

7. Operation

A. Operation

(1) Weather Radar modes
The weather radar system uses the principle of radio echoing. It works at a normal frequency of 9345 MHz. The peak power emitted is 125 W approx. The weather radar transceiver generates microwave energy in the form of electromagnetic pulses via an X-band wave guide to the antenna. When these pulses intercept an appropriate target, part of the energy is reflected back to the weather radar antenna then to the transceiver. For each case, the system uses a different mode of operation which allows to vary the scanning of the antenna, the timing of the pulses and the processing of the weather radar returns and of the predictive windshear events (if the function is activated). The electronics circuits of the transceiver measure the elapsed time between the transmission of the wave and the reception of the echo to determine the target distance (it takes around 12.36 microseconds for the electromagnetic wave to travel out and back for each nautical mile of target range).
The angular position of the target is detected by the angular position of the antenna in its scanning in azimuth. As the quantity of energy reflected to the antenna is proportional to the target density, the different levels of atmospheric disturbances (see table 1 below) are shown on the displays by different colors.
The detection of the turbulence areas are based on the Doppler phenomenon.

--------------------------------------------------------------------------

! LEVEL DETECTED ! PRECIPITATION RATE ! COLOR OF ECHOES !

!------------------------!-----------------------!-----------------------!

! Z1 < 20 dBz ! less than 1 mm/h ! black !

! 20 less than or equal ! from 1 to 4 mm/h ! green !

! to Z2 < 30 dBz ! ! !

! 30 less than or equal ! from 4 to 12 mm/h ! yellow !

! to Z3 < 40 dBz ! ! !

! 40 less than or equal ! 12 mm/h and above ! red !

! to Z4/Z5 < 50 dBz ! ! !

!------------------------!-----------------------!-----------------------!

! Turbulence ! 5 m/s ! magenta !

-------------------------------------------------------------------------!

Table 1: Color Correspondence Table

(2) Weather Radar modes
The weather radar system uses the principle of radio echoing. It works at a normal frequency of 9333 MHz. The peak power emitted is 120 W approx. The weather radar transceiver generates microwave energy in the form of electromagnetic pulses via an X-band wave guide to the antenna. When these pulses intercept an appropriate target, part of the energy is reflected back to the weather radar antenna then to the transceiver. For each case, the system uses a different mode of operation which allows to vary the scanning of the antenna, the timing of the pulses and the processing of the weather radar returns and of the predictive windshear events (if the function is activated). The electronics circuits of the transceiver measure the elapsed time between the transmission of the wave and the reception of the echo to determine the target distance (it takes around 12.36 microseconds for the electromagnetic wave to travel out and back for each nautical mile of target range).
The angular position of the target is detected by the angular position of the antenna in its scanning in azimuth. As the quantity of energy reflected to the antenna is proportional to the target density, the different levels of atmospheric disturbances (see table 1 below) are shown on the displays by different colors.
The detection of the turbulence areas are based on the Doppler phenomenon.

--------------------------------------------------------------------------

! LEVEL DETECTED ! PRECIPITATION RATE ! COLOR OF ECHOES !

!------------------------!-----------------------!-----------------------!

! Z1 < 20 dBz ! less than 1 mm/h ! black !

! 20 less than or equal ! from 1 to 4 mm/h ! green !

! to Z2 < 30 dBz ! ! !

! 30 less than or equal ! from 4 to 12 mm/h ! yellow !

! to Z3 < 40 dBz ! ! !

! 40 less than or equal ! 12 mm/h and above ! red !

! to Z4/Z5 < 50 dBz ! ! !

!------------------------!-----------------------!-----------------------!

! Turbulence ! 5 m/s ! magenta !

-------------------------------------------------------------------------!

Table 1: Color Correspondence Table

(3) Windshear mode (if the predictive windshear function is activated)
The WR/PWS, by a doppler mode, determines the wind field ahead of the aircraft.
By a mathematical treatment, the system determines the hazard factor (so-called "F factor") related to the danger of a windshear event.
An hazard factor exceeding a value of 0.13 and within 5NM ahead of the aircraft is considered as the presence of a dangerous event and a corresponding windshear alert is generated. The display of windshear hazard consits of an icon of red and black bands superimposed on the radar returns. As these events are dangerous during takeoff and landing maneuvers, the PWS mode is automatically activated below 2300 ft radio altimeter and at least one of the qualifier-A and one qualifier-B inputs have to be valid. Windshear detection operates automatically with the above-mentioned reasons, even if the radar function selector switch is set to OFF, but windshear switch has to be set to AUTO.
The windshear mode is transparent to the pilot until a windshear event is detected.
When a windshear event is detected, the system generates the appropriate annunciations (visual and aural) to the flight crew.
The WR/PWS generates a graphic symbol (icon) to the displays indicating where the windshear was detected.
The windshear function detection can operate either with weather radar modes activated or independently without these modes.
This is accomplished by sharing the antenna scanning:

in clockwise weather scan or windshear scan
in counterclockwise windshear scan.
In windshear mode, the TILT and GAIN are controlled automatically on the WR/PWS for the scanning.
However, the TILT displayed on the NDs is in accordance with this selected on the radar control panel.
When the weather radar transceiver fails, the amber message PRED W/S is displayed on the NDs associated with the amber messages:
NAV: PRED W/S DET FAULT on the upper ECAM DU,
PRED W/S DET in the INOP SYS item of the STATUS page on the SD.

NOTE: The system has to reject echoes due to ground clutter or moving surface.

NOTE: The pilot has to deselect windshear mode (AUTO/OFF switch to OFF) for the following reasons:

when the aircraft is at a gate area or in maintenance hangars to avoid radiating danger for persons
when nuisance aural alerts are generated.

NOTE: There is no danger of radiation to persons on the ground if the ATC switch on the ATC/TCAS control unit is set to OFF or STBY after landing, even if the windshear switch on the weather radar control unit is still at AUTO.

NOTE: In order to ensure optimum performance for the predictive windshear function, the radome must be at least equal to class B category 1.

(4) Windshear mode (if the predictive windshear function is activated)
The WR/PWS, by a doppler mode, determines the wind field ahead of the aircraft.
By a mathematical treatment, the system determines the hazard factor (so-called "F factor") related to the danger of a windshear event.
A hazard factor exceeding a value of 0.13 and within 5NM ahead of the aircraft is considered as the presence of a dangerous event and a corresponding windshear alert is generated. The display of windshear hazard consists of an icon of red and black bands superimposed on the radar returns. As these events are dangerous during takeoff and landing maneuvers, the PWS mode is automatically activated below 2300 ft radio altimeter and at least one of the two qualifier inputs (QB and QC or QB and QD) valid. These conditions enable automatic windshear detection operation even if, on the weather radar control unit, the 1/OFF/2 switch is at OFF; the WINDSHEAR/AUTO/OFF switch must be set to AUTO.
The windshear mode is transparent to the pilot until a windshear event is detected.
When a windshear event is detected, the system generates the appropriate annunciations (visual and aural) to the flight crew.
The WR/PWS generates a graphic symbol (icon) to the displays indicating where the windshear was detected.
The windshear function detection can operate either with weather radar modes activated or independently without these modes.
If the radar is already operating in a weather detection mode when a windshear is detected, no pilot intervention will be required.
If the radar is OFF when this event is detected, the radar operation will automatically change to WX+T mode (if selected range is less than 60NM) or WX mode (if selected range is more than 60NM), to display weather and windshear icons.
The selected range does not change.
In windshear mode, the TILT and GAIN are controlled automatically on the WR/PWS for the scanning.
However, the TILT displayed on the NDs is in accordance with this selected on the radar control panel.
When the weather radar transceiver fails, the amber message PRED W/S is displayed on the NDs associated with the amber messages:

NAV: PRED W/S DET FAULT on the upper ECAM DU,
PRED W/S DET in the INOP SYS item of the STATUS page on the SD.

The system 2 (if installed), has to be selected on the weather radar control unit to display windshear information.

NOTE: The system has to reject echoes due to ground clutter or moving surface.

NOTE: In some cases, the pilot has to deselect windshear mode (PWS/ OFF/AUTO switch to OFF) for the following reasons:

when the aircraft is at a gate area or in maintenance hangars to avoid radiating danger for persons,
when nuisance aural alerts are generated.

NOTE: In order to ensure optimum performance for the predictive windshear function, the radome must be at least equal to class B category 1.

(5) Logic of scanning mode

WR/PWS - Logic of scanning mode ** ON A/C NOT FOR ALL

The antenna scan pattern varies depending on the mode of operation.

(a) Weather radar scan pattern
In weather radar mode, the antenna scans a 180 deg. in azimuth and has tilt (pitch) coverage of plus or minus 15 deg.
Stabilization limits are plus or minus 25 deg. in the pitch axis and plus or minus 40 deg. in the roll axis.
An antenna scanning is performed in 4 seconds, this causes the transmission of 760 data words at each antenna scanning.
The weather radar system features a 4-second constant refresh rate of the WX image whatever the ranges selected on the CAPT and F/O EFIS control sections of the FCU.

(b) Weather and windshear scan pattern, no detected windshear event
When the system is placed into alternate weather/windshear scan pattern and no windshear event is detected, the antenna scan pattern is as follows:

clockwise weather scan with plus or minus 90 deg. of azimuth coverage and processing for weather
counterclockwise windshear scan with full plus or minus 90 deg. of azimuth coverage, but with windshear processing limited to the plus or minus 45 deg. sector.
However, the WR/PWS have to update the refresh rate of the WX image to 12 seconds due to sharing of processing between windshear and radar.

(c) Weather and windshear scan pattern, with windshear event detected
When the system is placed into alternate weather/windshear scan pattern and the system detects a windshear event, the antenna scan pattern is as follows:

clockwise weather scan, from minus 90 deg. to plus 90 deg.
counterclockwise windshear scan, from plus 90 deg. to minus 45 deg., with windshear processing between plus 45 deg. and minus 45 deg.
the next clockwise scan is from minus 45 deg. to plus 45 deg. to validate windshear
the next counterclockwise scan is from plus 45 deg. to minus 90 deg. to validate windshear. No processing occurs between plus 45 deg. and minus 90 deg.
clockwise WX scan, from minus 90 deg. to plus 90 deg.
The sequence is repeated as long as windshear event is detected. If a windshear event is not detected, the system reverts to the alternating weather/windshear scan pattern described above.
The refresh rate of the WX image is minimum 16 sesonds due to sharing processing between radar and windshear event detection.

(d) Windshear scan pattern
When the system operates in windshear mode only, the scan pattern is plus or minus 45 deg. azimuth coverage on both the clockwise and counterclockwise scans.
This mode occurs if the operator has placed the weather radar to OFF mode.
Windshear data are processed during both directions of antenna scanning.
In this case the windshear mode works transparent to the flight crew until a windshear event is detected.
The refresh rate of the display is 8 seconds.

(6) Radar Multiscan mode
The Multiscan mode manages the antenna beam tilts automatically. The antenna tilts are controlled for optimum weather detection during each phase of flight. This mode uses a low and high beam to examine short and long range, even while on the ground. Data for display is automatically selected from the upper beam, lower beam or both depending on the flight regime, clutter situation and optimum weather detection requirements.

NOTE: At each initial flight of the Multiscan radar transceiver, the transceiver needs to be calibrated (each transceiver must be turned on for approximately four minutes) during a short period in stable flight conditions. Before the initial calibration step, it is possible that the weather image shows an excessive ground clutter. If the initial calibration step is not performed or is uncompleted, the Multiscan radar transceiver will calibrate itself during the next flights.

(a) Cycle times
Cycle time refers to the total amount of time that the Multiscan radar scans for information during various modes of operation of the radar. Total cycle time can vary between 6 and 12 seconds. The radar updates some portion of the weather, windshear (depending on the mode of operation) on every radar antenna scan. Therefore, a new data set is completed after every radar sweep. If you start from time zero, a completely new data set of information is obtained by the radar at the end of the one cycle.

NOTE: The display update rate (Ref. para. E.(4)(a)) is what the flight crew actually sees. Cycle time describes what Multiscan is doing in the background.

(b) Weather mode scan pattern

Weather Radar - Multisan Scan Pattern ** ON A/C NOT FOR ALL

When Multiscan operates in the weather mode only two radar scans are utilized. One four-second sweep is utilized for the high beam and one four-second sweep is utilized for the low beam. Therefore, the total cycle time is 8 seconds (Ref.Fig.010).

(c) Windshear mode scan pattern
The Windshear mode is automatically activated below 2.300 FT AGL. The time required for one radar sweep changes from 4 to 2.8 seconds due to the fact that the radar sweep changes from 180° to 120°. In windshear mode, the first antenna scan (left to right) is utilized for the Multiscan high beam. The second scan (right to left) is a windshear scan. The third scan (left to right) is utilized for Multiscan low beam. The fourth scan (right to left) is, again, a windshear scan. Thus, total cycle time during windshear mode is 11.2 seconds (Ref.Fig.010).

B. Timing of Transmitted Pulses in WX/MAP Mode and in Doppler Mode (Turbulence) and W/S Mode

Weather radar - Pulse Transmission Timing Diagram ** ON A/C NOT FOR ALL

in the WX and MAP modes, the basic period of pulse transmission-reception is 5.25 ms. This causes an interrogation frequency (PRF) of 190 Hz. As two pulses are transmitted (6 micros and 18 micros), the specified PRF is 380 Hz.
Both 6-micros and 18-micros pulses are used to cover all range scales i.e. from 0 to 320 NM.
The 6-micros wide pulse echo is processed for ranges from 0 to 20 NM.
The 18-micros wide pulse echo is processed for ranges greater than 40 NM. The 6-micros and 18-micros pulse echoes are processed for ranges between 20 and 40 NM
in the turbulence mode (HIGH PRF), the HIGH PRF and LOW PRF pulses are interlaced. This causes simultaneous WX/MAP and TURBULENCE information.
The 6-micros wide pulses 1 to 9 are transmitted at 1600 Hz and are used for turbulence detection.
The 18-micros wide pulse 10 is used for the WX/MAP mode.
The high frequency of the PRF required for turbulence detection (1600 Hz) limits the range of this detection to 40 NM.
in windshear mode (VERY HIGH PRF) the 1.5-micros wide pulses are transmitted at 6000 Hz. The sequence of transmitted RF pulses consists of two staggered pulse trains, each with the different carrier frequency. Each pulse train has a PRF of 3000 Hz, providing 10 NM (minimum selected range on EFIS control section).

C. Pulse Duration and Range Timing

Weather radar - Pulse Transmission Timing Diagram ** ON A/C NOT FOR ALL

This section provides the timing details for the transmitting and the processing of radar data.

(1) Epoch timing (non-windshear modes)
An epoch is the time interval in which a radial or radar data is processed. The time is equal to the size of the radar processing element in degrees divided by the antenna scan rate. The rate does not include any added dithering delays. Specifications for the range, element size, scan rate, and process epoch period are shown in Table a.

-----------------------------------

! Range ! All ranges !

!----------------!----------------!

! Element size ! 0.375 degree !

!----------------!----------------!

! Scan Rate ! 45 deg/sec !

!----------------!----------------!

! Epoch ! 8.333 ms !

! Period ! +/- 5 microsec!

-----------------------------------

Table a. Epoch Timing Table

(a) Transmitter pulse width values
The transmitter pulse widths are 6.0 and 20.0 microseconds . Accuracy of the pulse width is +/- 0.2 microsecond.

(b) Transmitter pulse pattern

Weather Radar - Windshear Transmit Pulse Pattern ** ON A/C NOT FOR ALL

The transmitter pulse pattern is as follows for all selected ranges. One 20 microseconds pulse and four 6 microseconds pulses will be transmitted during each epoch. The Pulse Repetition Frequency (PRF) for the 6 microseconds pulses is 1839Hz (543.83 microseconds). Figure 011 shows the non-windshear pulse pattern.

(2) Process epoch timing (windshear mode)
An epoch is the time interval in which a radial of radar data is processed. The process epoch timing is maintained by DSP1. The rate does not include any added dithering delays. Specifications for the element size, scan rate and process epoch period are shown in Table b.

-----------------------------------

! Range ! All Ranges !

!----------------!----------------!

! Element Size ! 1.0 degree !

!----------------!----------------!

! Scan Rate ! 45 deg/sec !

!----------------!----------------!

! Epoch Period ! 22.975 ms !

-----------------------------------

Table b. Process Epoch Timing Table

(a) Transmitter pulse width
The transmitter pulse width is 2 microseconds for windshear mode.

(b) Transmitter pulse pattern
The pulse repetition frequency is 3000HZ (333.3333 microseconds) and a total of 64 pulses is transmitted per epoch (Ref.Fig.012).

(3) Range resolution/timing
The requirements for the range resolution and timing for the system are as follows:

(a) Windshear mode
The unit takes data samples out to a range of 5NM. Sixty-four samples are taken, the sample resolution is 150 meters +/- 6 meters. The receiver starts sampling 4.0 microseconds after the end of the transmit epoch.

(b) Non-windshear mode
The transceiver splits the radar return into two separate analog channels: in-phase(I) and quadrature(Q) channels. The transceiver simultaneously samples each channel the number of times shown in Table c. per transmit pulse, converting the radar return signal into digital format data. Receiver sampling starts at a time equivalent to a range of 0.5NM after the end of the transmitter pulse.

------------------------------------------------------------------

! Pulsewidth ! Sampled Range ! Number of Sample Taken !

!----------------!-------------------!---------------------------!

! 6 microsec ! 41.424 NM ! 247 !

!----------------!-------------------!---------------------------!

! 20 microsec ! 331.392 NM ! 504 !

------------------------------------------------------------------

Table c. Receiver sample vs. Range

The resolution of each individual sample is defined using the following equation:

Sample Length = [(range)/sample quantity]*K

Where:

range = sampled range

sample quantity = 512

K = 12.34 microseconds/NM (electromagnetic propagation constant)

The 512 range bins from the 40NM short range data set (6 microseconds tx pulses) and the 512 range bins from the 320NM long range data set (20 microseconds tx pulses) are interpolated/decimated to produce the final 256 data bin set suitable for output at the selected range. The 256 range bins are then linearly expanded to fill the 512 ARINC 708A data bus range bins. The transceiver displays radar returns with a range accuracy of 5% or 1/2NM whichever is larger.

(4) Receiver selectivity
Selectivity of the receiver filter bandwidth is controlled to match the current transmitter pulse length as shown in Table d. The specified filter bandwidths listed are single sided 3dB bandwidths.

-----------------------------------------

! Pulsewidth ! Filter !

!-------------------!-------------------!

! 2.0 microsec ! 250 kHz !

!-------------------!-------------------!

! 6.0 microsec ! 100 kHz !

!-------------------!-------------------!

! 20.0 microsec ! 25 kHz !

-----------------------------------------

Table d. Receiver Selectivity vs. Transmitter Pulsewidth

(a) Display updates
Display updates occur at a minimum rate of two updates per 26.67 seconds worst case with three problem cases selecting long range weather and windshear mode operating.

D. Controls and Indicating
The various system controls are grouped on the weather radar control unit and on the EFIS control sections of the FCU.
Radar image control on the NDs is achieved through the scale selector switches located on the Captain and First Officer EFIS control sections of the FCU.

(1) Weather radar control unit

Weather Radar - Control Unit ** ON A/C NOT FOR ALL

The face of the weather radar control unit includes the following controls:

(a) A mode selector switch, item 2, which enables the selection of the WX, WX/TURB or MAP function.

(b) A TILT selector switch, item 3, which enables the control of the antenna elevation.
Antenna position is read in degrees, opposite the notch on the switch:

Either from 0 to 15 deg. upwards (UP), or
From 0 to 15 deg. downwards (DN).

(d) A switch, item 1, with three stable positions 1/OFF/2, which enables the activation of the transceiver.

(e) A PWS switch, item 4, with two stable positions AUTO/OFF, which enables the selection of the windshear function.
This function is inoperative until the windshear function is activated.
The face of the control unit is provided with integral lighting. The INTEG LT potentiometer enables lighting adjustment. The potentiometer is located on the panel 111VU, at the left aft section of the center pedestal 100VU.

(f) A MAN/TILT/AUTO switch, item 6, which enables the selection of manual tilt or automatic tilt.

(2) Weather radar control unit

Weather Radar - Control Unit ** ON A/C NOT FOR ALL

The face of the weather radar control unit includes the following controls:

(a) A mode selector switch, item 2, which enables the selection of the WX, WX+T, TURB or MAP function.

(b) A TILT selector switch, item 3, which enables the control of the antenna elevation.
Antenna position is read in degrees, opposite the notch on the switch:

Either from 0 to 15 deg. upwards (UP), or
From 0 to -15 deg. downwards (DN).

(d) A switch, item 1, with three stable positions 1/OFF/2, which enables the selection of the transceiver 1 or 2 and the deactivation of the transceivers.

(e) A PWS/OFF/AUTO switch, item 4, which enables the selection of the windshear function.
The face of the control unit is provided with integral lighting. The INTEG LT potentiometer enables lighting adjustment. The potentiometer is located on the panel 111VU, at the left aft section of the center pedestal 100VU.

(f) A GCS switch, item 6, with a Ground Clutter Suppression (GCS) function which is activated in Multiscan AUTOMATIC mode (this is the default position). In manual mode, the GCS is never activated.

(g) A Multiscan switch, item 7, which enables the selection between MANUAL mode and Multiscan AUTOMATIC mode.

(3) EFIS control section (on the FCU)
In this part, the controls related to the selection of WX and W/S functions are described.

(a) A mode selector switch, item 1, made up of a rotary switch enables the selection of the ROSE or ARC function for display of a weather radar image on the CAPT and F/O NDs.
Windshear information is available in ARC and ROSE mode.

(b) A scale selector switch, item 2, common to EFIS, FMGS and radar systems, enables the selection of 10, 20, 40, 80, 160 or 320 operation range in nautical miles (NM) for display of the weather radar image on the CAPT and F/O NDs.
Windshear information is presented in the 10 NM minimum range and on other selected ranges. Morever, yellow radial lines are displayed to indicate the W/S included location.

NOTE: In the ARC or ROSE mode, if the CAPT or the F/O switches to the OFF mode FM, the offside weather image will also be transferred on the ND. Only one scale selector switch can then control the weather radar image display.

(4) Lighting/LOUDSPEAKER control panel
CAPT and F/O lighting/LOUDSPEAKER control panels 301VU and 500VU which are connected to CAPT and F/O NDs, include ND concentric potentiometers for adjusting the brightness of the image displayed on the NDs. The outer knob of each potentiometer controls the brightness of the radar image only, item 3.

E. Utilization of Controls and Indicating

(1) Radar operation areas

Weather Radar - Radar Precaution Areas ** ON A/C NOT FOR ALL

Special precautions:
On the ground, on the weather radar control-unit, before you move the WXR/PWS control switch from position OFF to position 1 or 2 (in dual configuration) and select a DISPLAY mode different from OFF, make sure that, in an arc of +/- 135° degrees on the two sides of the aircraft centerline:

There are no persons and no large metal objects (for example a hangar) at less than 5 meters from the antenna that moves.
There is no fuel at less than 1.5 meters from the antenna that moves.
During maintenance, when you start the system test, make sure that there are no persons and no objects in the radome.

(2) Operation of the transceiver
The transceiver is always supplied in order to achieve maintenance function. On the weather radar control unit, after selection of the radar mode, the system switch has to be set to ON position to set the transceiver in operation.

NOTE: No pre-heating time is necessary for the operation of the weather radar transceiver.

NOTE: When the aircraft is parked, the TEST mode on the MCDU must be preferably selected as a safety precaution.

On either EFIS control section of the FCU, the mode selector switch must be set to the ARC or ROSE position to obtain the image display on the corresponding ND.

NOTE: The radar transceiver is de-activated when the system switch on the weather radar control unit is set to the OFF position.

(3) Utilization of the weather radar control unit

Weather Radar - Control Unit ** ON A/C NOT FOR ALL

(4) Utilization of the weather radar control unit - Mode selection switch (item 2)
The modes (WX, WX/TURB, MAP) are selected by placing the notch provided in the mode selector switch in front of the engraving of the function selected.

WX
This mode corresponds to the normal operation in weather detection. It provides disturbances up to 320 NM.
The radar images are displayed on the NDs in four colors (black, green, yellow, red); their intensity corresponds to the strength of the return signal.
WX/TURB
This mode corresponds to the operation in weather and turbulence detections. Turbulence detection is limited to the first 40 NM regardless of the weather radar range selected and displayed.
Turbulence areas are displayed on the NDs in magenta.
All turbulent/non turbulent areas beyond 40 NM are displayed in the conventional black, green, yellow and red as in the weather (WX) mode.

NOTE: There is no detection of turbulence in clear sky.

MAP
This mode is only used for display of the ground map. A combination of transceiver gain, antenna position (TILT) and range selection enables the display of a larger area and the identification of major changes in the ground map (e.g. a sea cost, a lake, a mountain, an island...).
The color display follows the color mentioned in correspondence table (see table 1 - para. 7. A.)
If the image is too bright, due to too great reflection intensity, it can be dimmed by the GAIN potentiometer, item 5.

(5) Utilization of the weather radar control unit - System selection and start up: 1/OFF/2 switch (item 1)
This switch enables:

the selection and activation of the transceiver 1 or 2 (if the second transceiver is installed)
the suppression of the radar image on the NDs when these NDs are in the ARC or ROSE mode.

(6) Utilization of the weather radar control unit - Gain control (item 1)
The GAIN potentiometer enables the manual control of transceiver sensitivity in the WX, WX+T, TURB and MAP modes.
Clockwise rotation of the GAIN potentiometer increases the gain towards the MAX position.
When the potentiometer is rotated fully clockwise, the CAL position provides preset calibrated transceiver gain level (minimum receiver sensitivity).
When the GAIN potentiometer is the CAL position, no indication appears in the R lower corner of the NDs.
When the GAIN potentiometer is in a position other than CAL, the MAN GAIN indication is displayed in white.
In windshear mode, the gain control is automatic for the WR/PWS scanning.

(7) Utilization of the weather radar control unit - TILT control (item 3)
The TILT selector switch enables the variation of the antenna elevation angle in 1/4 deg. steps on a non-linear scale graduated in degrees, within a range of +15 deg. (UP) to -15 deg. (DOWN) in relation to a horizontal plane defined by the stabilization system.
This antenna elevation angle (TILT), selected on the radar control unit, is displayed in cyan in the R lower corner of the ND in this form: MAN +/-XX.X°.
If the antenna elevation angle is different from the TILT selector switch position, a red ANT failure warning message replaces the TILT indication in the R lower corner of the ND.
In windshear mode, the tilt control is automatic for WR/PWS scanning.
In windshear mode, the tilt indication on the NDs is replaced by the green PWS SCAN indication.

(8) Utilization of the weather radar control unit - PWS/AUTO/OFF switch (item 2)
In AUTO position, the windshear detection is automatic if altitude is lower than 2300 ft and qualifiers A and B are valid.
This automatic operation can be inhibited when the switch is in the OFF position.

(9) Utilization of the weather radar control unit - Ground clutter suppression (item 4)
Activation of the GND CLTR SPRS switch, in weathers modes (WX, WX+T, TURB), reduces the intensity of the ground clutter.
These ground returns are replaced by black areas on the radar image when the GND CLTR SPRS switch is placed in ON position.

(10) Utilization of the weather radar control unit - TILT control value (item 3)
The TILT selector switches enable the variation of the antenna elevation angle in 1/4 deg. steps on a non-linear scale graduated in degrees, within a range of +15 deg. (UP) to -15 deg. (DOWN) in relation to a horizontal plane defined by the stabilization system.
This antenna elevation angle is displayed in cyan in the R lower corner of the ND and progresses in steps of 0.25 deg.
If the antenna position is different from the TILT selector switch position, a red ANT failure warning message replaces the TILT indication in the R lower corner of the ND. In windshear mode, the tilt is automatic and the tilt displayed on ND is always the selection on the radar control section although different in the antenna.
In the windshear position, the tilt control is automatic in the WR/PWS for the scanning. However, the tilt displayed on ND is in accordance with the one selected on the radar control unit.

(11) Utilization of the weather radar control unit - OFF/AUTO PWS switch (item 4)
In AUTO position, the windshear detection is automatic if altitude is lower than 2300 ft and qualifiers A and B are valid. This automatic operation can be inhibited when the switch is in the OFF position.

(12) Utilization of the weather radar control unit - MAN/AUTO TILT switch (item 6)
this mode is used to select between manual mode or autotilt mode.
In MAN position, all controls operate as described in the manual mode.
In AUTO position, the system operates in autotilt mode (automatic tilt and no action of the crew is necessary).

(13) Utilization of the EFIS control sections and lighting/LOUDSPEAKER control panels

EFIS Control Sections and EFIS Switching Panels ** ON A/C NOT FOR ALL

(a) Mode selector switch (item 1)
This mode selector switch enables the image display on the corresponding ND whenever the ARC or ROSE mode is selected and the transceiver is supplied. In that case, the radar image is displayed in the background of the navigation image. If neither ROSE or ARC mode is selected, the message W/S CHANGE MODE is shown on both NDs, if there is a windshear alert. The pilot is advised to select ARC or ROSE mode to see the W/S icon. The color depends on the W/S alert level.

(b) Scale selector switch (item 2)
This selector switch enables the display of the range selected for an optimum use of the radar image on the corresponding ND. For each of the following ranges: 10, 20, 40, 80, 160 and 320, four concentric range arcs are displayed respectively spaced 2.5, 5, 10, 20, 40 and 80 NM, when the mode selector switch is in the ARC position. Only 2 range arcs are displayed in the ROSE mode.
Windshear information is presented in the 10 NM range only. If a windshear alert is generated but the selected range is greater than 10 NM, the message W/S: SET RNG 10 NM is shown on the NDs. In this case, the pilot is advised to select the 10 NM range. The color depends on the W/S alert level.

(c) Radar image brightness control (item 3)
The ND potentiometer enables the adjustment of brightness and contrast of radar echoes in relation to the navigation image, which is superimposed.
However, the adjustment range does not allow total extinction of the image. The OFF position of the potentiometer corresponds to the minimum brightness. The BRT position corresponds to the maximum brightness.

NOTE: A photoelectric cell associated with each ND also adjusts image brightness as a function of ambient light variations.

(14) Weather radar data displayed on the NDs

Weather radar - Data Displayed on the NDs ** ON A/C NOT FOR ALL

On the figure, the details A) and B) respectively correspond to the ARC and ROSE ND modes for which the display of the radar image is possible.
Messages inform the crew of the tilt angle and gain selected on the weather radar control unit. Other messages indicate the failures which affect the operation of the radar system. All these messages are displayed in the R lower corner of each ND whenever a radar image is selected.

NOTE: Tilt information and gain selection are displayed on the ND when no failure warning message is generated, or when the TEST mode is not selected.

The various failures which can affect the radar image are listed in decreasing order of importance. If several failures occur, only the most important one is displayed (Ref. details C) and D) on the figure).
Two types of failures can affect the radar system:

(a) Failures which result in the loss of the radar image
The corresponding messages are displayed in red

- WXR : indicates an overheating of the Display Unit (DU)

- WXR : indicates a failure of the weather radar transceiver

R/T

- WXR : indicates a failure of the weather radar antenna

ANT

- WXR : indicates a failure of the weather radar control unit

CTL

- WXR : indicates an error of comparison between the range

RNG from the EFIS control section and the copy data received

on the DMC via the radar data bus.

(b) Failures which do not affect the radar image
The corresponding messages are displayed in amber

- WXR : indicates the loss of the transceiver calibration

WEAK

- PRED : indicates a failure of the windshear function

W/S

- WXR : indicates an attitude failure from the ADIRU

ATT

- NO : indicates a failure of the autotilt function

AUTOTILT

- WXR : indicates the loss of the radar antenna stabilization

STAB

- WXR : indicates the selection of the radar TEST mode.

TEST

(15) Weather radar data displayed on the NDs

Weather radar - Data Displayed on the NDs ** ON A/C NOT FOR ALL

NOTE: Tilt information and gain selection are displayed on the ND when no failure warning message is generated, or when the TEST mode is not selected.

(a) Failures which result in the loss of the radar image.
The corresponding messages are displayed in red:

- WXR : indicates an overheating of the Display Unit (DU)

- WXR : indicates a failure of the weather radar transceiver

R/T

- WXR : indicates a failure of the weather radar antenna

ANT

- WXR : indicates a failure of the weather radar control unit

CTL

- WXR : indicates an error of comparison between the range

RNG from the EFIS control section and the copy data received

on the DMC via the radar data bus.

(b) Failures which do not affect the radar image.
The corresponding messages are displayed in amber:

- WXR : indicates the loss of the transceiver calibration

WEAK

- PRED : indicates a failure of the windshear function

W/S

- WXR : indicates an attitude failure from the ADIRU

ATT

- NO : indicates a failure of the Multiscan function

AUTOTILT

- WXR : indicates the loss of the radar antenna stabilization

STAB

- WXR : indicates the selection of the radar TEST mode.

TEST

(16) Weather radar data displayed on the NDs - Operational message

Weather radar - Data Displayed on the NDs ** ON A/C NOT FOR ALL

(operational message that does not affect the radar image)
The following message is displayed in green instead of the TILT value

- PWS SCAN : indicates that the weather radar operates in windshear mode only

(weather radar system selector switch set to OFF and windshear

mode selector switch set to AUTO on weather radar control

unit).

On ground the qualifier logic has to be satisfied.

(17) Windshear data displayed (Ref. table 2 below) (if the predictive windshear function is activated)

Windshear - Data Displayed on the NDs ** ON A/C NOT FOR ALL

(a) Windshear indications
The location of a windshear phenomenon is indicated to the crew by means of an icon superimposed on the radar image.
This icon consists of alternating red and black arcs. For 10 NM range selection and above, yellow radial lines appear at the edges and start beyond the windshear event. These lines, superimposed on the radar image, continue to the edge of the display area to provide directional information for the event.
The windshear data are always displayed even if the system selector switch on the radar control unit is set to OFF.
The windshear switch on the radar control unit has to be set to AUTO.
When on the radar control unit, the weather radar system selector switch is set to OFF and the windshear mode selector switch is set to AUTO, the green "PWS SCAN" indication is displayed on the bottom right-hand corner of the NDs instead of the tilt indication to inform the crew that the weather radar operates in windshear mode only.

(b) Windshear alert

Windshear - Windshear Alert Ranges and Altitudes ** ON A/C NOT FOR ALL

Windshear - Windshear Alert Levels and Locations ** ON A/C NOT FOR ALL

1 Alert levels
There are three alert levels defined in function of event seriousness and distance from the aircraft. The weather radar provides the crew with visual and aural warnings which vary in function of the level detected.

a Windshear warning alert (level 3)
This alert corresponds to the most dangerous phenomenons.
It is generated for windshear events detected within +/- 0.25 NM from the longitudinal axis of the aircraft and within +/- 30 deg. scan of the aircraft heading.
On the ground, the maximum range is 3 NM. In flight, the maximum range is reduced to 1.5 NM.
During takeoff, level 3 covers ranges from 0 to 1.5 NM, from 50 to 1200 ft Above Ground Level (AGL). During landing, this coverage is from 1.5 to 0.5 NM, from 370 to 50 ft.
Range reduction is a linear function of altitude: at 370 ft, range is equal to 1.5 NM and reaches 0.5 NM at 50 ft.
During takeoff, this warning is inhibited from the time the aircraft attains 100 kts and until it reaches 50 ft AGL.
Level 3 warning is inhibited below 50 ft (in approach phase) and above 1200 ft.
The windshear warning alert is announced by:

an aural warning message: GO AROUND WINDSHEAR AHEAD in approach or WINDSHEAR AHEAD, WINDSHEAR AHEAD at takeoff, generated by the radar synthesized voice.
a visual warning: red W/S AHEAD message on the PFD.

Display priority on PFD is given to level 3.
The computer has to determine whether the aircraft is taking-off or landing to generate the aural warning message "GO AROUND, WINDSHEAR AHEAD" or "WINDSHEAR AHEAD, WINDSHEAR AHEAD".
Transition between the GO AROUND, WINDSHEAR AHEAD and WINDSHEAR AHEAD, WINDSHEAR AHEAD aural warning messages is controlled by the GEAR UP discrete input.

b Windshear caution alert (level 2)
This level covers the events detected in a region from 0 to 3 NM, within +/- 30 deg. of the aircraft heading but outside the windshear warning alert region (level 3).
This caution alert is inhibited:

during takeoff, from the time the aircraft attains 100 kts and until it reaches 50 ft AGL,
during landing, below 50 ft AGL.

There should be no windshear caution alert (level 2) above 1200 ft.
The windshear caution alert is announced by:

an aural warning: MONITOR RADAR DISPLAY
a visual warning: amber W/S AHEAD message on the PFD.

c Windshear advisory alert (level 1)
This level covers the events located within 5 NM from the aircraft, within +/- 30 deg. of the aircraft heading but outside the windshear warning and caution alert regions (levels 2 and 3).
There should be no windshear advisory alert (level 1) above 1500 ft.
No aural or visual warnings are provided for this advisory alert: only the windshear icon is superimposed on the radar image.
The weather radar transmits the windshear alerts following their detection order. A maximum of 8 events can be transmitted. Therefore, alerts of different levels can be generated simultaneously.

-------------------------------------------------------------------------------

! ALERTS ! PFD ! ND ! AURAL WARNING !

!-------------!-----------------!-------------------!-------------------------!

! Advisory ! ! windshear icon ! !

!-------------!-----------------!-------------------!-------------------------!

! Advisory ! ! PWS SCAN ! !

! in windshear! ! (GREEN) ! !

! mode only ! ! ! !

!-------------!-----------------!-------------------!-------------------------!

! Caution ! W/S AHEAD ! windshear icon ! MONITOR !

! ! (AMBER) ! ! RADAR DISPLAY !

!-------------!-----------------!-------------------!-------------------------!

! Warning ! W/S AHEAD ! windshear icon ! during takeoff: !

! ! (RED) ! ! WINDSHEAR AHEAD !

! ! ! ! WINDSHEAR AHEAD !

! ! ! ! during landing: !

! ! ! ! GO AROUND !

! ! ! ! WINDSHEAR AHEAD !

-------------------------------------------------------------------------------

Table 2: Windshear Data Displayed

(18) Windshear data displayed (Ref. table 2 below) (if the predictive windshear function is activated)

Windshear - Data Displayed on the NDs ** ON A/C NOT FOR ALL

(b) Windshear alert

Windshear - Windshear Alert Ranges and Altitudes ** ON A/C NOT FOR ALL

Windshear - Windshear Alert Levels and Locations ** ON A/C NOT FOR ALL

a Windshear warning alert (level 3)
This alert corresponds to the most dangerous phenomenons.
It is generated for windshear events detected within +/- 0.25 NM from the longitudinal axis of the aircraft and within +/- 40 deg. scan of the aircraft heading.
On the ground, the maximum range is 3 NM. In flight, the maximum range is reduced to 1.5 NM.
During takeoff, level 3 covers ranges from 0.5 to 1.5 NM, from 50 to 1200 ft Above Ground Level (AGL). During landing, this coverage is from 1.5 to 0.5 NM, from 375 to 50 ft.
Range reduction is a linear function of altitude: at 375 ft, range is equal to 1.5 NM and reaches 0.5 NM at 50 ft.
During takeoff, this warning is inhibited from the time the aircraft attains 100 kts and until it reaches 50 ft AGL.
Level 3 warning is inhibited below 50 ft (in approach phase) and above 1200 ft.
The windshear warning alert is announced by:

an aural warning message: GO AROUND WINDSHEAR AHEAD in approach or WINDSHEAR AHEAD, WINDSHEAR AHEAD at takeoff, generated by the radar synthesized voice.
a visual warning: red W/S AHEAD message on the PFD.

Display priority on PFD is given to level 3.
The FWC has determine whether the aircraft is taking-off or landing to generate the aural warning: GO AROUND, WINDSHEAR AHEAD or WINDSHEAR AHEAD, WINDSHEAR AHEAD.
Transition between the GO AROUND, WINDSHEAR AHEAD and WINDSHEAR AHEAD, WINDS HEAR AHEAD aural warning messages is controlled by the GEAR UP discrete input.

b Windshear caution alert (level 2)
This level covers the events detected in a region from 0 to 3 NM, within +/- 25 deg. of the aircraft heading but outside the windshear warning alert region (level 3).
This caution alert is inhibited:

during takeoff, from the time the aircraft attains 100 kts and until it reaches 50 ft AGL,
during landing, below 50 ft AGL.

There should be no windshear caution alert (level 2) above 1200 ft.
The windshear caution alert is announced by:

an aural warning: MONITOR RADAR DISPLAY
a visual warning: amber W/S AHEAD message on the PFD.

c Windshear advisory alert (level 1)
This level covers the events located within 5 NM from the aircraft, within +/- 40 deg. of the aircraft heading but outside the windshear warning and caution alert regions (levels 2 and 3).
There should be no windshear advisory alert (level 1) above 1500 ft.
No aural or visual warnings are provided for this advisory alert: only the windshear icon is superimposed on the radar image.
The weather radar transmits the windshear alerts following their detection order. A maximum of 8 events can be transmitted. Therefore, alerts of different levels can be generated simultaneously.

-------------------------------------------------------------------------------

! ALERTS ! PFD ! ND ! AURAL WARNING !

!-------------!-----------------!-------------------!-------------------------!

! Advisory ! ! windshear icon ! !

!-------------!-----------------!-------------------!-------------------------!

! Caution ! W/S AHEAD ! windshear icon ! MONITOR !

! ! (AMBER) ! ! RADAR DISPLAY !

!-------------!-----------------!-------------------!-------------------------!

! Warning ! W/S AHEAD ! windshear icon ! during takeoff: !

! ! (RED) ! ! WINDSHEAR AHEAD !

! ! ! ! WINDSHEAR AHEAD !

! ! ! ! during landing: !

! ! ! ! GO AROUND !

! ! ! ! WINDSHEAR AHEAD !

-------------------------------------------------------------------------------

Table 2: PWS OPERATIVE - Windshear Data Displayed

NOTE: Between 2300ft and 1500ft, no warning is triggered: the PWS is in standby in this boundary, without any cockpit effect.

(19) Windshear warning displayed (Ref. table 3 below) (if the predictive windshear function is activated)

Messages Displayed on ND and upper ECAM DU ** ON A/C NOT FOR ALL

(a) Windshear flags on NDs
When a windshear fault occurs, an amber PRED W/S message comes into view. The radar image remains available if this fault does not affect the radar modes or detection function.
A detected fault is displayed when:

the aircraft is on the ground or the flap and slat control lever is in a position different from 0.
the windshear AUTO/OFF switch on the radar control unit is set to AUTO (the fault message is not displayed when the switch is set to OFF).

(b) Warning display on Upper ECAM Display Unit
A detected windshear fault is indicated by the following amber messages:

NAV: PRED. W/S DET FAULT on EWD.

PRED. W/S DET on SD INOP SYSTEM area.
This message is associated to the indications presented on the NDs.
When the windshear AUTO/OFF switch is set to OFF on the weather radar control unit, a green or amber PRED W/S OFF memo message is presented to the crew.
The color of this message depends on the flight phases.

-------------------------------------------------------------------------------

! ! UPPER DU ECAM ! ND ! AURAL WARNING !

!-------------!-----------------!-------------------!-------------------------!

! PWS ! NAV: ! PRED W/S ! Single chime !

! SYSTEM ! PRED. W/S DET ! (AMBER) ! !

! FAULT ! FAULT ! ! !

! ! (AMBER) ! ! !

!-------------!-----------------!-------------------!-------------------------!

! WINDSHEAR ! PRED. W/S OFF ! ! !

! AUTO/OFF ! (GREEN or AMBER)! ! !

! SWITCH ON ! ! ! !

! CONTROL ! ! ! !

! UNIT IN ! ! ! !

! OFF ! ! ! !

! POSITION ! ! ! !

-------------------------------------------------------------------------------

Table 3: PWS INOPERATIVE - Warning Data Displayed

(20) Record in the Flight Data Interface Unit (FDIU)
The FDIU receives, for recording, the following PWS data through the DMCs:

W/S caution alert (level 2)
W/S warning alert (level 3)
W/S AUTO/OFF
W/S internal fault
W/S external fault
DMCs/FWCs PWS pin program status.

This data, except the PWS pin program status, is only transmitted from the DMCs if the DMCs/FWCs PWS pin program is valid (grounded).

(21) Windshear warning displayed (Ref. table 3 below) (if the predictive windshear function is activated)

Messages Displayed on ND and upper ECAM DU ** ON A/C NOT FOR ALL

the aircraft is on the ground or the flap and slat control lever is in a position different from 0.
the windshear AUTO/OFF switch on the radar control unit is set to AUTO (the fault message is not displayed when the switch is set to OFF).

(b) Warning display on EWD
A detected windshear fault is indicated by the following amber messages:

NAV: PRED. W/S DET FAULT on EWD.

-------------------------------------------------------------------------------

! ! EWD ! ND ! AURAL WARNING !

!-------------!-----------------!-------------------!-------------------------!

! PWS ! NAV: ! PRED W/S ! Single chime !

! SYSTEM ! PRED. W/S DET ! (AMBER) ! !

! FAULT ! FAULT ! ! !

! ! (AMBER) ! ! !

!-------------!-----------------!-------------------!-------------------------!

! WINDSHEAR ! PRED. W/S OFF ! ! !

! AUTO/OFF ! (GREEN or AMBER)! ! !

! SWITCH ON ! ! ! !

! CONTROL ! ! ! !

! UNIT IN ! ! ! !

! OFF ! ! ! !

! POSITION ! ! ! !

-------------------------------------------------------------------------------

Table 3: PWS INOPERATIVE - Warning Data Displayed

(22) Record in the Flight Data Interface Unit (FDIU)
The FDIU receives, for recording, the following PWS data through the DMCs:

W/S caution alert (level 2)
W/S warning alert (level 3)
W/S AUTO/OFF
W/S internal fault
W/S external fault
DMCs/FWCs PWS pin program status.

This data, except the PWS pin program status, is only transmitted from the DMCs if the DMCs/FWCs PWS pin program is valid (grounded).

F. Reconfiguration switching

Weather Radar - Control and Indicating ** ON A/C NOT FOR ALL

In normal configuration, the weather radar transceiver receives the altitude information from its corresponding ADIRU.
In case of ADIRU1 failure, the pilot can select the altitude information from the ADIRU3.
This selection is through the AIR DATA selector switch installed on panel 8VU, on the center pedestal.

** ON A/C NOT FOR ALL

8. Test

A. BITE Description

(1) General
The BITE facilitates maintenance on in-service aircraft. It detects and identifies a failure related to the system.
The BITE of the WR/PWS is situated in the radar transceiver and through two ARINC 429 low-speed buses (an input bus from the CFDIU and an output bus to the CFDIU).
The BITE:

transmits permanently weather radar system 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 (EFIS control section, ADIRUs, RAs),
transmits to the CFDIU the result of the tests performed and self-tests,
can communicate with the CFDIU through the MCDU menus.
acquires the general maintenance parameters (UTC, date, A/C ident...) and command codes from the CFDIU.

The PWS interface with the CFDIU is composed of:

an ARINC 429 low speed bus from the CFDIU.
The data sent by the CFDIU are:

---------------------------------------------------------

! LABEL ! PARAMETER ! FORMAT !

---------------------------------------------------------

! 125 ! UTC ! BCD !

! 155 ! AIRCRAFT CONFIGURATION 1 ! DISC !

! 156 ! AIRCRAFT CONFIGURATION 2 ! DISC !

! 227 ! COMMAND ! DISC !

! 260 ! DATE ! BCD !

! 301 ! AIRCRAFT IDENT ! ISO !

! 302 ! AIRCRAFT IDENT ! ISO !

! 303 ! AIRCRAFT IDENT ! ISO !

---------------------------------------------------------

an ARINC 429 low speed output bus to the CFDIU:
The data sent to the CFDIU are:

---------------------------------------------------------

! LABEL ! PARAMETER ! FORMAT !

---------------------------------------------------------

! 354 ! LRU IDENTIFICATION ! ISO !

! 356 ! FAULT MESSAGES ! ISO !

! 377 ! EQUIPMENT IDENTIFICATION ! BCD !

---------------------------------------------------------

The BITE can operate in two operating modes:

* in normal mode, to report continuously the failures of all

classes, depending on the maintenance flight phase,

* in interactive mode, to provide an interactive dialog with

an operator using an MCDU.

NOTE: The WR/PWS complies with Specification ABD0048, issue C.

(2) General
The BITE facilitates maintenance on in-service aircraft. It detects and identifies a failure related to the system.
The BITE of the WR/PWS is situated in the radar transceiver and through two ARINC 429 low-speed buses (an input bus from the CFDIU and an output bus to the CFDIU).
The BITE:

transmits permanently weather radar system 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 (EFIS control section, ADIRUs, RAs),
transmits to the CFDIU the result of the tests performed and self-tests,
can communicate with the CFDIU through the MCDU menus.
acquires the general maintenance parameters (UTC, date, A/C ident...) and command codes from the CFDIU.
The BITE can operate in two operating modes:
in normal mode, to report continuously the failures of all classes, depending on the maintenance flight phase
in interactive mode, to provide an interactive dialog with an operator using an MCDU.

NOTE: The WR/PWS complies with Specification ABD0048, issue C.

(3) Normal mode
During the normal mode the BITE monitors cyclically the status of the WR/PWS. 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.

(4) Interactive mode
The interactive mode can only be activated on the ground and through the line key adjacent to the RADAR 1 indication, presented on the SYSTEM REPORT/TEST/NAV page of any MCDU.
This mode enables communication between the CFDIU and the BITE of the weather radar transceiver by means of the MCDU.

Weather Radar - Maintenance Test Procedure - Access to the RADAR page ** ON A/C NOT FOR ALL

The interactive mode is composed of:

LAST LEG REPORT

Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 1) ** ON A/C NOT FOR ALL

This report contains the fault messages related to the external or internal failures (class 1 and 2) recorded during the last flight leg.
The following tables give the list of the failure messages which can be reported and indicate the failure class assigned to them as defined by the CFDIU standard.

-------------------------------------------------------------

! Reported Internal Failures !

!-----------------------------------------------------------!

! MESSAGE ! CLASS ! ATA !

-------------------------------------------------------------

! WXR1 (1SQ1) ! 1 ! 34-41-33 !

! WXR ANTENNA (11SQ) ! 1 ! 34-41-11 !

! WXR CTL PNL (3SQ)/WXR1 (1SQ1) ! 1 ! 34-41-12 !

! WXR MOUNTING TRAY (9SQ) ! 1 ! 34-41-37 !

-------------------------------------------------------------

! Reported External Failures !

!-----------------------------------------------------------!

! MESSAGE ! CLASS ! ATA !

-------------------------------------------------------------

! ADIRU1 (1FP1) BUS ADR/WXR1 (1SQ1) ! 3 ! 34-12-34 !

! ADIRU3 (1FP3) BUS ADR/WXR1 (1SQ1) ! 3 ! 34-12-34 !

! ADIRU1 (1FP1) BUS IR/WXR1 (1SQ1) ! 1 ! 34-12-34 !

! ADIRU3 (1FP3) BUS IR/WXR1 (1SQ1) ! 1 ! 34-12-34 !

! FCU (3CA) BUS CP-L/WXR1 (1SQ1) ! 1 ! 22-81-12 !

! FCU (3CA) BUS CP-R/WXR1 (1SQ1) ! 1 ! 22-81-12 !

! CFDIU (1TW)/WXR1 (1SQ1) ! 3 ! 31-32-34 !

! RA1 (2SA1)/WXR1 (1SQ1) ! 3 ! 34-42-33 !

! RA2 (2SA2)/WXR1 (1SQ1) ! 3 ! 34-42-33 !

! RA1 (2SA1)+RA2 (2SA2)/WXR1 (1SQ1) ! 1 ! 34-42-33 !

! POWER SUPPLY INTERRUPT ! 1 ! 24-00-00 !

-------------------------------------------------------------

NOTE: Failure of one radio altimeter is a class 3 failure whereas it becomes a class 1 failure when two radio altimeters are faulty.

PREVIOUS LEGS REPORT
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 1) ** ON A/C NOT FOR ALL
This report contains the fault messages related to the external or internal failures (class 1 and 2) recorded during the previous 63 flight legs.
LRU IDENTIFICATION
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 1) ** ON A/C NOT FOR ALL
Allows to display the P/N, the S/N and the SW/N of the equipment.
GND SCANNING
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 2) ** ON A/C NOT FOR ALL
Based on the monitoring and fault analysis during flight, provides information of the failures detected while using this function.
The WR/PWS peripheral monitoring and internal cycle tests are used to detect transient failures.
By pressing the line key adjacent to the failure message, the operator is allowed to the corresponding Trouble Shooting Data. The peripheral monitoring and WR/PWS internal cyclic tests are used to detect transient failures.
TROUBLE SHOOTING DATA
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 2) ** 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
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 3) ** ON A/C NOT FOR ALL
Allows to display the class 3 faults recorded during the last flight leg.
GROUND REPORT
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 3) ** ON A/C NOT FOR ALL
Allows to present the class 1, 2 or 3 internal failures detected on ground.
These failures differ from those displayed on the LAST LEG REPORT and CLASS 3 FAULTS.
By pressing the line key adjacent to the failure message, the operator is allowed to access to the corresponding Trouble Shooting Data.
TEST
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 4) ** ON A/C NOT FOR ALL
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 5) ** ON A/C NOT FOR ALL
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 6) ** ON A/C NOT FOR ALL
Allows a check of the correct operation of the WR/PWS on ground.
This test can be performed by:
either selecting the test function on the LCD of the WR transceiver
or through the CFDS by selecting on the MCDU the test function on the RADAR 1 main menu page.
At the end of the BITE TEST, the test pattern comes into view.
Weather Radar - Test Pattern ** ON A/C NOT FOR ALL

NOTE: If a failure of the windshear system is detected during the BITE TEST, the windshear flags come into view.
If the failure does not affect the radar mode, the test pattern stays available.
If the failure affects the radar mode, nothing is shown.

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).

(5) Normal mode
During the normal mode the BITE monitors cyclically the status of the WR/PWS. 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.

(6) Interactive mode
The interactive mode can only be activated on the ground and through the line key adjacent to the RADAR 1 indication, presented on the SYSTEM REPORT/TEST/NAV page of any MCDU.
This mode enables communication between the CFDIU and the BITE of the weather radar transceiver by means of the MCDU.

Weather Radar - Maintenance Test Procedure - Access to the RADAR page ** ON A/C NOT FOR ALL

The interactive mode is composed of:

LAST LEG REPORT

Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 1) ** ON A/C NOT FOR ALL

-------------------------------------------------------------

! Reported Internal Failures !

!-----------------------------------------------------------!

! MESSAGE ! CLASS ! ATA !

-------------------------------------------------------------

! WXR1 (1SQ1) ! 1 ! 34-41-33 !

! WXR ANTENNA (11SQ) ! 1 ! 34-41-11 !

! WXR CTL PNL (3SQ)/WXR1 (1SQ1) ! 1 ! 34-41-12 !

! WXR MOUNTING TRAY (9SQ) ! 1 ! 34-41-37 !

-------------------------------------------------------------

! Reported External Failures !

!-----------------------------------------------------------!

! MESSAGE ! CLASS ! ATA !

-------------------------------------------------------------

! ADIRU1 (1FP1) BUS ADR/WXR1 (1SQ1) ! 3 ! 34-12-34 !

! ADIRU3 (1FP3) BUS ADR/WXR1 (1SQ1) ! 3 ! 34-12-34 !

! ADIRU1 (1FP1) BUS IR/WXR1 (1SQ1) ! 1 ! 34-12-34 !

! ADIRU3 (1FP3) BUS IR/WXR1 (1SQ1) ! 1 ! 34-12-34 !

! FCU (3CA) BUS CP-L/WXR1 (1SQ1) ! 1 ! 22-81-12 !

! FCU (3CA) BUS CP-R/WXR1 (1SQ1) ! 1 ! 22-81-12 !

! CFDIU (1TW)/WXR1 (1SQ1) ! 3 ! 31-32-34 !

! RA1 (2SA1)/WXR1 (1SQ1) ! 3 ! 34-42-33 !

! RA2 (2SA2)/WXR1 (1SQ1) ! 3 ! 34-42-33 !

! RA1 (2SA1)+RA2 (2SA2)/WXR1 (1SQ1) ! 1 ! 34-42-33 !

! GPWC (1WZ)/WXRi (1SQi) ! 1 ! 34-48-34 !

! POWER SUPPLY INTERRUPT ! 1 ! 24-00-00 !

-------------------------------------------------------------

NOTE: Failure of one radio altimeter is a class 3 failure whereas it becomes a class 1 failure when two radio altimeters are faulty.

PREVIOUS LEGS REPORT
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 1) ** ON A/C NOT FOR ALL
This report contains the fault messages related to the external or internal failures (class 1 and 2) recorded during the previous 63 flight legs.
LRU IDENTIFICATION
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 1) ** ON A/C NOT FOR ALL
Allows to display the P/N, the S/N and the SW/N of the equipment.
GND SCANNING
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 2) ** ON A/C NOT FOR ALL
Based on the monitoring and fault analysis during flight, provides information of the failures detected while using this function.
The WR/PWS peripheral monitoring and internal cycle tests are used to detect transient failures.
By pressing the line key adjacent to the failure message, the operator is allowed to the corresponding Trouble Shooting Data. The peripheral monitoring and WR/PWS internal cyclic tests are used to detect transient failures.
TROUBLE SHOOTING DATA
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 2) ** 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
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 3) ** ON A/C NOT FOR ALL
Allows to display the class 3 faults recorded during the last flight leg.
GROUND REPORT
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 3) ** ON A/C NOT FOR ALL
Allows to present the class 1, 2 or 3 internal failures detected on ground.
These failures differ from those displayed on the LAST LEG REPORT and CLASS 3 FAULTS.
By pressing the line key adjacent to the failure message, the operator is allowed to access to the corresponding Trouble Shooting Data.
TEST
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 4) ** ON A/C NOT FOR ALL
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 5) ** ON A/C NOT FOR ALL
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 6) ** ON A/C NOT FOR ALL
Allows a check of the correct operation of the WR/PWS on ground.
This test can be performed by:
either selecting the test function on the LCD of the WR transceiver
or through the CFDS by selecting on the MCDU the test function on the RADAR 1 main menu page.
At the end of the BITE TEST, the test pattern comes into view.
Weather Radar - Test Pattern ** 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).

(7) Normal mode
During the normal mode the BITE monitors cyclically the status of the WR/PWS. 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.

(8) Interactive mode
The interactive mode can only be activated on the ground and through the line key adjacent to the RADAR 1 (or 2) indication, presented on the SYSTEM REPORT/TEST/NAV page of any MCDU.
This mode enables communication between the CFDIU and the BITE of the weather radar transceiver by means of the MCDU.

Weather Radar - Maintenance Test Procedure - Access to the RADAR page ** ON A/C NOT FOR ALL

The interactive mode is composed of:

LAST LEG REPORT

Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 1) ** ON A/C NOT FOR ALL

-------------------------------------------------------------

! Reported Internal Failures !

!-----------------------------------------------------------!

! MESSAGE (i = 1 or 2) ! CLASS ! ATA !

-------------------------------------------------------------

! WXRi (1SQi) ! 1 ! 34-41-33 !

! WXR ANTENNA (11SQ) ! 1 ! 34-41-11 !

! WXR CTL PNL (3SQ)/WXRi (1SQi) ! 1 ! 34-41-12 !

! WXR MOUNTING TRAY (9SQ) ! 1 ! 34-41-37 !

-------------------------------------------------------------

! Reported External Failures !

!-----------------------------------------------------------!

! MESSAGE (i = 1 or 2) ! CLASS ! ATA !

-------------------------------------------------------------

! ADIRU1 (1FP1) BUS ADR/WXR1 (1SQ1) ! 3 ! 34-12-34 !

! ADIRU2 (1FP2) BUS ADR/WXR2 (1SQ2) ! 3 ! 34-12-34 !

! ADIRU3 (1FP3) BUS ADR/WXRi (1SQi) ! 3 ! 34-12-34 !

! ADIRU1 (1FP1) BUS IR/WXR1 (1SQ1) ! 1 ! 34-12-34 !

! ADIRU2 (1FP2) BUS IR/WXR2 (1SQ2) ! 1 ! 34-12-34 !

! ADIRU3 (1FP3) BUS IR/WXRi (1SQi) ! 1 ! 34-12-34 !

! ADIRU1+3 (1FP1+3)/WXR1 (1SQ1) ! 1 ! 34-12-34 !

! ADIRU2+3 (1FP2+3)/WXR2 (1SQ2) ! 1 ! 34-12-34 !

! QUALIFIER B1/2/WXRi (1SQi) ! 1 ! 79-33-11 !

! QUALIFIER C1/2/WXRi (1SQi) ! 1 ! 34-12-34 !

! QUALIFIER D1/2/WXRi (1SQi) ! 1 ! 34-12-34 !

! FCU (3CA) BUS CP-L/WXRi (1SQi) ! 1 ! 22-81-12 !

! FCU (3CA) BUS CP-R/WXRi (1SQi) ! 1 ! 22-81-12 !

! CFDIU (1TW)/WXRi (1SQi) ! 3 ! 31-32-34 !

! RA1 (2SA1)/WXRi (1SQi) ! 3 ! 34-42-33 !

! RA2 (2SA2)/WXRi (1SQi) ! 3 ! 34-42-33 !

! RA1 (2SA1)+RA2 (2SA2)/WXRi (1SQi) ! 1 ! 34-42-33 !

! GPWC (1WZ)/WXRi (1SQi) ! 1 ! 34-48-34 !

! POWER SUPPLY INTERRUPT ! 1 ! 24-00-00 !

-------------------------------------------------------------

NOTE: Failure of one radio altimeter is a class 3 failure whereas it becomes a class 1 failure when two radio altimeters are faulty.

PREVIOUS LEGS REPORT
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 1) ** ON A/C NOT FOR ALL
This report contains the fault messages related to the external or internal failures (class 1 and 2) recorded during the previous 63 flight legs.
LRU IDENTIFICATION
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 1) ** ON A/C NOT FOR ALL
Allows to display the P/N, the S/N and the SW/N of the equipment.
GND SCANNING
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 2) ** ON A/C NOT FOR ALL
Based on the monitoring and fault analysis during flight, provides information of the failures detected while using this function.
The WR/PWS peripheral monitoring and internal cycle tests are used to detect transient failures.
By pressing the line key adjacent to the failure message, the operator is allowed to the corresponding Trouble Shooting Data. The peripheral monitoring and WR/PWS internal cyclic tests are used to detect transient failures.
TROUBLE SHOOTING DATA
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 2) ** 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
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 3) ** ON A/C NOT FOR ALL
Allows to display the class 3 faults recorded during the last flight leg.
GROUND REPORT
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 3) ** ON A/C NOT FOR ALL
Allows to present the class 1, 2 or 3 internal failures detected on ground.
These failures differ from those displayed on the LAST LEG REPORT and CLASS 3 FAULTS.
By pressing the line key adjacent to the failure message, the operator is allowed to access to the corresponding Trouble Shooting Data.
TEST
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 4) ** ON A/C NOT FOR ALL
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 4) ** ON A/C NOT FOR ALL
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 5) ** ON A/C NOT FOR ALL
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 5) ** ON A/C NOT FOR ALL
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 6) ** ON A/C NOT FOR ALL
Weather Radar - Maintenance Test Procedure - Sub-menus (Sheet 6) ** ON A/C NOT FOR ALL
Allows a check of the correct operation of the WR/PWS on ground.
This test can be performed by:
either selecting the test function on the LCD of the WR transceiver
or through the CFDS by selecting on the MCDU the test function on the RADAR 1 (or 2) main menu page.
At the end of the BITE TEST, the test pattern comes into view.
Weather Radar - Test Pattern ** ON A/C NOT FOR ALL
Weather Radar - Test Pattern ** 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. Self-Test

Weather Radar - Test Pattern ** ON A/C NOT FOR ALL

A quick check of the correct operation of the WR/PWS installation can be performed by activating the test function:

either through the CFDS by applying the Radar functional test procedure on the Multipurpose Control and Display Unit (MCDU)

or by pressing the TEST pushbutton switch located on the face of the transceiver. When a fault is detected, it is stored and made available to the front panel Liquid Crystal Display (LCD) when the TEST pushbutton switch is pressed. The LCD is used as a maintenance aid to check the operational status of the WR/PWS.
Once this TEST pushbutton switch is pressed, the LCD shows TEST IN PROGRESS.
The self-test takes from 5 to 10 seconds to complete.
At the end of the test, the LCD shows RADAR OK, INPUT OK if no faults were detected in either the radar or inputs connections.
Pressing the return pushbutton switch enables access to the fault main menu.
* If radar faults were found during the self-test, the following messages can be displayed:

R/T FAULT

ANT FAULT

CON FAULT

WG SWITCH FAULT

INDICATOR FAULT

COOLING FAULT

* If inputs faults were found during the self-test, the following messages can be displayed:

NO RAD ALT

NO ALTITUDE IN

NO AIR DATA IN

NO HEADING INPUT

[Rev.10 from 2021] 2026.04.02 06:23:20 UTC