Operation Manual Part 2

Aerosoft – Digital Aviation
CRJ-70 & CRJ-900
AOM PART 2
Systems Description
VOL
5
5-1-112
26-Jul-2017
TERRAIN / OBSTACLE AWARENESS ALERTING AND DISPLAY
The GPWS is supplied with a terrain and obstacle database. This database enables the GPWS to compute
possible collisions with terrain or obstacles based on a comparison of the computed flight path. Either way the
system first triggers cautions and if the flight path does not change then it triggers a warning.
To display terrain data on the MFD, press the RDR/TERR button on the display control panel.
Green, yellow and rot dots with varying density display the terrain relative to the aircrafts position.
Terrain more than 2,000ft below the aircraft or within 400ft of the nearest runway elevation is not displayed.
In case a terrain warning is triggered, the terrain display is automatically selected on both multifunctional
displays and the range defaults to 10nm.
In case the aircraft is safely above all terrain, the terrain is displayed without any relation to the currents
aircraft altitude. Furthermore, two numbers appear on the MFD – the upper one shows the highest displayed
altitude (in hundreds of feet MSL) and the lower one shows the lowest altitude. Terrain within 400 feet
(vertical) of the nearest runway elevation is not displayed.
Obstacle cautions are displayed in solid yellow.
Obstacle warnings are displayed in solid red.
Terrain
Obstacle
Caution
GND PROX lights flashing &
CAUTION TERRAIN, CAUTION
TERRAIN aural warning
GND PROX lights flashing &
CAUTION OBSTACLE, CAUTION
OBSTACLE aural warning
Warning
PULL UP lights flash and
TERRAIN, TERRAIN PULL UP aural
warning
PULL UP lights flash and
OBSTACLE, OBSTACLE PULL UP
aural warning
TERRAIN CLEARANCE FLOOR
The terrain clearance floor mode triggers the same warnings as mode 4 but calculations in the background are
different as this mode is for flying in landing configuration and based on a database of hard-surfaced runways
with more than 3,500ft length.