BOMBARDIER BD-100-1A10, Operating Manual

Page: 489 / 544

NAVIGATION
Sep 13/2004 Flight Crew Operating Manual Volume 2
REV 1 CSP 100-6
17-01-13
TERRAIN AWARENESS WARNING SYSTEM (TAWS)
DESCRIPTION
The primary purpose of the terrain awareness warning system (TAWS) is to provide alerts and warnings to avoid controlled
flight into terrain (CFIT) and to provide detected windshear warning. The system provides the flight crew with aural alert
messages and visual annunciations and displays in the event that the boundaries of any alerting envelopes are exceeded.
The TAWS contains three systems in one line replaceable unit.
- Ground proximity
- Terrain/obstacle awareness
- Windshear systems
The Ground Proximity Warning System (GPWS) produces warnings that require action based on real time input to
the GPWS. These warnings help prevent CFIT and are categorized into 5 modes. Each mode has a distinct aural and visual
alerts. The GPWS is also capable of providing a sixth mode, which can include altitude related callouts and excessive bank
angle callout. The displays provide the PULL UP and GND PROX GPWS annunciations on the PFD.
Mode 7 provides windshear caution or warning alerts if threshold values along the flight path and perpendicular to the flight
path are exceeded. The displays provide WINDSHEAR annunciations of the PFD.
The Enhanced Ground Proximity Warning Computer (EGPWC) processes all inputs and provides all aural and visual alerts
and warnings.
A warning annunciation indicates a prediction of impact with terrain. All annunciations are displayed on pilot and copilot
PFDs.
COMPONENTS AND OPERATION
The MFD control panel provides for the selection of the terrain (TR/WX) display on the respective MFD, while the DCP
is used to display TR/WX on the PFD. Graphical terrain data is automatically displayed on the MFD when a terrain hazard
is encountered. Each time the TAWS computer commands a terrain popup, the MFD automatically commands terrain over-
lay to be added to the current format if the onside PFD is not displaying terrain and if the MFD format is compatible with
terrain. The PFD commands the normal range to 10 NM. If the current MFD format is incompatible with terrain, the format
will be changed to PPOS with TR selected, with a 10nm range. Regardless of the current format, selecting TR/WX will
automatically select terrain for display. Similarly, selection of WX or WX/LX automatically deselects terrain.
Terrain range is selectable from the on-side DCP RANGE knob. with selected ranges up to 300 nm. If the display range is
at a value greater than 300 nm when the pilot selects terrain, the display range will automatically reduce to 300 nm. On the
Challenger 300, range can be selected up to 600 nm when in plan map format. If terrain data has been selected for display,
selection of display ranges greater than 300 nm will be inhibited.
The TAWS WARN control panel, located on the center instrument panel, provides for the inhibiting of GS, FLAPS, aural
warnings and TERRAIN.
- GS
- A TAWS GS WARN OFF status message is displayed when the switch is set to OFF. This switch is used by
the pilot to mute nuisance “glideslope” warnings. This switch is normally selected when a backcourse ap-
proach is conducted
- FLAPS
- A TAWS FLAPS OFF status message is displayed when the switch is set to OFF. This switch is used by the
pilot to mute related GPWS warnings when a landing will be attempted with flaps not at 30 degrees
- TERRAIN
- A TAWS TERR OFF status message is displayed when the switch is set to OFF. This switch is used by the
pilot to deselect the terrain function of the TAWS