User's Manual Part 2

T
2
CAS / Part No. 9000000
SYSTEM DESCRIPTION AND INSTALLATION MANUAL
34-43-20
15 Feb 2003
Use or disclosure of information on this page is subject to the restrictions in the proprietary notice of this document.
4--85
E. TAWS/RWS Discrete Inputs
The specifics of the following discrete (e.g. ground/open, +28 Vdc/open, definition of
open/ground states, etc.) are aircraft dependant and will be defined in the ASDB.
(1) Landing Gear Down
The Landing Gear Down input Discrete is used on installations where T
2
CAS is
performing both the TAWS and RWS functions.
This Discrete input is shared between the TCAS and TAWS functions with separate
internal wiring. The
T
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CAS computer unit monitors this discrete to update the landing
gear position.
(2) Landing Flap
The Landing Flap Discrete input is used for GPWS Mode 2, GPWS Mode 4 and
Windshear Caution/Warning Calculations.
This discrete indicates whether or not the Flaps are in the correct position for aircraft
landing.
(3) Terrain Inhibit
When the Terrain Inhibit switch is engaged, all TAWS aural and visual alerts are
inhibited. The Auto Pop--up feature, being based on these alerts, is suppressed as
well. The terrain image, if selected for display, is removed and a ”TERRAIN
INHIBITED” message is displayed. This inhibit feature is typically used to avoid
nuisance alerts during operation around airports that are not in the terrain database,
or during approach under VFR conditions at airports in close proximity to terrain
features. The Terrain Inhibit must be manually de--selected.
(4) Steep Approach
The Steep Approach Discrete input enables Mode 1 Steep Approach alert biasing.
This discrete is typically enabled by an Autopilot Flight Deck switch and is used to
reduce nuisance alerts during aircraft steep approach landings.
(5) Glideslope Inhibit
The Glideslope Inhibit Discrete input is used to inhibit Mode 5 Glideslope alerting.
This discrete would typically be enabled by a Flight Deck switch during back--course
approaches (see ILS Back--Course).
(6) Glideslope Cancel
The Glideslope Cancel Discrete input is typically a Flight Deck switch that is used to
cancel Glideslope alerting when an unreliable Glideslope is expected or when
maneuvering is required during ILS final approach.