Technical data

Product Specification
HIF-2121/R5 CAGE CODE: 97896 SCALE: NONE SIZE: A DWG NO: 965-1176-601 REV: D SHEET 8
1.2 Purpose
The Product Specification describes all of the system functions and design criteria for the MKVI and MKVIII Enhanced
Ground Proximity Warning System (EGPWS). This document serves two major purposes. First, it describes the system
functions for EGPWS customers. Secondly, it provides a system description for regulatory authorities.
1.3 System Overview
The purpose of the Enhanced Ground Proximity Warning System is to help prevent accidents caused by Controlled Flight into
Terrain (CFIT). The system achieves this objective by accepting a variety of aircraft parameters as inputs, applying alerting
algorithms, and providing the flight crew with aural alert messages and visual annunciations and displays in the event that the
boundaries of any alerting envelope are exceeded. Figure 1.3-1 provides an overall system block diagram.
WINDSHEAR
DETECTION
AND ALERTING
ALGORITHMS
EGPWC
AUDIO ALERT
MESSAGES
AIRCRAFT
PARAMETERS
VISUAL ALERT
MESSAGES
TERRAIN DISPLAY
DATA
GPWS
ALGORITHMS
TERRAIN
AWARENESS &
OBSTACLE
ALERTING AND
DISPLAY
ALGORITHMS
TERRAIN
CLEARANCE
FLOOR
ALGORITHMS
ALERT LAMPS
AND EFIS
DISPLAY
FLIGHT DECK
SPEAKERS AND
INTERPHONE
EFIS NAV.
DISPLAY OR Wx
RADAR
INDICATOR
AIRCRAFT
SENSORS
AND
SYSTEMS
O
U
T
P
U
T
P
R
O
C
E
S
S
I
N
G
I
N
P
U
T
P
R
O
C
E
S
S
I
N
G
AURAL
CALLOUTS
WINDSHEAR
DETECTION
AND ALERTING
ALGORITHMS
FIGURE 1.3-1: ENHANCED GROUND PROXIMITY WARNING SYSTEM
The system comprises the following groups of components:
• Aircraft sensors and other systems providing input signals
• The Enhanced Ground Proximity Warning Computer (EGPWC)
• Flight deck audio systems (speakers and interphone)
• Alert (caution and warning) lamps and/or digital outputs to EFIS displays (for alert and system status messages)
• Weather radar indicator for display of terrain and limited EFIS display support.
• Switching relay(s) or Display Switching Unit (DSU) when required for switching display inputs from
weather display to terrain display.
The system is designed to be fully compatible with normal operations of commercial aircraft: unwanted alerts will be very
rare if the flight crew maintains situational awareness with respect to the terrain and if the crew follows correct avoidance
procedures for any significant windshear activity.
Several main alerting functional areas are integrated into the EGPWC, which is a single Line Replaceable Unit (LRU). Each
function is configuration module selectable.