WXR system - general Description

Control

These components supply weather radar (WXR) system control:

· Left and right EFIS control panels

· Weather radar control panel.

 

System Inputs

These components supply signals to the WXR transceiver for predictive windshear:

· Air data inertial reference system sends air data for the PWS function

· Radio altimeters send altitude to enable or disable PWS during takeoff and approach

· Autothrottle switch packs enable PWS during takeoff

· Landing gear lever switch sends a landing gear down discrete to enable PWS during approach

· An air/ground relay sends an air/ground discrete for flight leg counting.

 

System Outputs

The weather radar transceiver sends these signals out for

predictive windshear:

· PWS video to the WXR/TERR relays

· PWS warnings or cautions to the GPWS to prioritize any callouts

·     Audio inhibit to TCAS when there is a PWS warning

·     Audio to the REU for PWS.

 

Display

WXR data shows on the navigation displays (NDs). The weather data from the WXR receiver/transmitter (R/T) goes to the weather radar/terrain (WXR/TERR) relays.

The ground proximity warning computer (GPWC) controls and switches the relays. If TERR is selected on the EFIS control panel or there is a Terrain Awareness/Terrain Clearance Floor warning from the GPWC, then the EGPWS terrain data shows on the navigation display (ND). If TERR is not selected and there are no EGPWS warnings, WXR data shows on the ND.

Antenna

The WXR antenna sends the RF pulses and receives the RF returns. The R/T gets air data inertial reference unit (ADIRU) pitch and roll data for antenna stabilization.

Receiver/Transmitter (R/T)

The primary component of the WXR system is the weather radar R/T. The WXR R/T does these functions:

· Transmits RF pulses

· Processes the RF returns

· Detects windshear events and sends warnings and cautions to the flight crew

· Supplies the WXR display data.

 

WXR SYSTEM - COMPONENT LOCATION - FLIGHT COMPARTMENT

WXR System Components

The weather radar control panel is on the P8 aft electronic panel in the flight compartment.

WXR System Interface Components

These are the flight compartment components that have an interface with the WXR system:

· Left EFIS control panel (P7)

· Right EFIS control panel (P7)

· Left inboard display unit (P1)

· Right inboard display unit (P3)

· IRS select switch on the navigation/displays source select panel (P5).

 

 

 

WXR SYSTEM - COMPONENT LOCATION - FORWARD EQUIPMENT COMPARTMENT AND NOSE RADOME

General

The WXR antenna is on the forward bulkhead behind the nose radome.

These are the WXR system components in the forward

equipment compartment:

· WXR R/T

· WXR R/T mount.

 

CAUTION: WHEN REMOVING OR INSTALLING THE WEATHER

RADAR R/T, CARE SHOULD BE TAKEN TO AVOID

DAMAGE TO THE CAPTAIN PITOT AIR DATA

MODULE FLEXIBLE HOSE.