User's Manual Part 1

T
2
CAS / Part No. 9000000
SYSTEM DESCRIPTION AND INSTALLATION MANUAL
34-43-20
15 Feb 2003
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1--11
Figure 1--4. Basic TCAS ll Installation
(2) TAWS Functional Description
The T
2
CAS TAWS function provides guidance to prevent Controlled Flight Into
Terrain (CFIT). This is accomplished by using vertical speed, ground speed, track
angle, flight path angle, latitude, longitude, flap status, steep approach status, static
air temperature, roll angle, pressure altitude and radio altitude inputs along with a
built--in database for determination of alerts and display of terrain information.
The followin g advanced functional capabilities are featured in the T
2
CAS TAWS
function.
(a) Collision Prediction and Alerting (CPA) Mode
This mode provides medium -- term (caution) and short--term (warning) alerts
when the predicted flight path will bring the aircraft dangerously close to nearby
terrain. When operative, CPA replaces RTCA DO-- 161A reactive modes 1 and 2
since it offers superio r safety margins for CFIT prevention due to its predictive
capabilities.