WXR SYSTEM - COMPONENT LOCATION - FLIGHT COMPARTMENT

WEATHER RADAR SYSTEM

Purpose

The weather radar (WXR) system supplies these visual

indications:

· Weather conditions

· Windshear events

· Land contours.

Description

WXR operates on the same principle as an echo. The WXR system transmits radio frequency (RF) pulses in a 180 degree area forward of the airplane. Objects reflect the pulses back to the receiver. The receiver processes the return signal to show weather, terrain, and windshear events.

Display

The WXR returns show in four different colors on the navigation displays (ND). Colors of the indications give the crew information about the intensity of the returns.

Abbreviations and Acronyms

· ac - alternating current

· ADF - automatic direction finder

· ADIRS - air data inertial reference system

· ADIRU - air data inertial reference unit

· alt - altitude

· ant - antenna

· app - approach

· ARINC - Aeronautical Radio, Inc.

· arpt - airport

· AZ - azimuth

· baro - barometric

· BITE - built-in test equipment

· BL - buttock line

· CAL - calibrate

· capt - captain

· CDU - control display unit

· con - control

· CP - control panel

· CPU - central processing unit

· dc - direct current

· DEU - display electronics unit

· DH - decision height

· dn - down

· EFIS - electronic flight instrument system

· EGPWS - enhanced ground proximity warning system

· EL - elevation

· elex - electric

· F/O - first officer

· FMC - flight management computer

· FMCS - flight management computing system

· FPV - flight path vector

· fwd - forward

· gnd - ground

· GS - ground speed

· hPa - hectopascals

· in - inch

· intlk - interlock

· IRS - inertial reference system

· kg - kilograms

· L - left

· lb - pounds

· mag - magnetic

· max - maximum

· MDA - minimum descent altitude

· MHz - megahertz

· MINS - minimums

· MTRS - meters

· nav - navigation

· NCD - no computed data

· ND - navigation display

· NM - nautical miles

· OK - good or pass

· PFD - primary flight display

· pos - position

· PRF - pulse repetition frequency

· PWS - predictive windshear

· R - right

· rad - radio

· RF - radio frequency

· R/T - receiver/transmitter

· sta - station

· stab - stabilization

· stb - stabilization

· std - standard

· TAS - true air speed

· TCAS - traffic alert and collision avoidance

· trk - track

· TRU - true

· V - volts

· VOR - very high frequency omnidirectional range

· wpt - waypoint

· WX - weather

· WX/TURB - weather/turbulence

· WX+TURB - weather+turbulence

· WXR - weather radar

· Z - zulu (universal coordinated time)

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

Date: 2016-01-14; view: 2466