EGPWS LINE MAINTENANCE MANUAL

CAGE CODE: 97896 SCALE: NONE SIZE: A DWG NO.: 060-4199-180 REV: SHEET 9 of 57

2 DESCRIPTION AND OPERATION

2.1 GENERAL SYSTEM DESCRIPTION

The purpose for the Enhanced Ground Proximity Warning System (EGPWS) is to help prevent accidents causedby Controlled Flight Into Terrain (CFIT), obstacles, or severe windshear. The Enhanced Ground Proximity WarningComputer (EGPWC) accepts a variety of aircraft sensors and system inputs and applies alerting algorithms toprovide the flight crew with aural messages and visual annunciations when the boundaries of alerting envelopes areexceeded. A graphic depiction of terrain and obstacles within the range selected on an EFIS or Weather Radardisplay may be configured for enhanced situational awareness with respect to terrain and obstacles. Figure 2-1provides an overall system block diagram.

EGPWC

AUDIO ALERTMESSAGES

AIRCRAFT PARAMETERS

VISUAL ALERTMESSAGES

TERRAIN DISPLAYDATA

GPWSALGORITHMS

TERRAINAWARENESS

ALERTING ANDDISPLAY

ALGORITHMS

TERRAINCLEARANCE

FLOORALGORITHMS

WINDSHEARDETECTION

AND ALERTINGALGORITHMS

ALERT LAMPSOR

EFIS DISPLAY

FLIGHT DECKSPEAKERS

ANDINTERPHONE

EFIS DISPLAYOR

Wx RADARINDICATOR

AIRCRAFTSENSORS

ANDSYSTEMS

OUTPUT

PROCESSING

INPUT

PROCESSING

AURALCALLOUTS

Figure 2-1: Enhanced Ground Proximity Warning System

The EGPWS is comprised of the following:

Aircraft sensors and systems providing input signals

The Enhanced Ground Proximity Warning Computer (EGPWC)

Flight deck audio systems (speaker and interphone)

Alert lamps and/or EFIS or EICAS displays (for alert and system status messages)

EFIS Navigation Display (ND), Multi-Function Display (MFD), or Weather Radar Indicator for display of terrain

Switching relay(s) when required for switching display inputs from weather display to terrain display