User's Manual Part 1

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.
1--9
Figure 1--2. TCAS/Mode S Communication
The TCAS function generates both RAs and TAs when the TA/RA mode is selected.
The two types of advisories correspond to time-- based protection zones around the
aircraft. The airspace around the TCAS aircraft where an RA is annunciated
represents the warning area, while the larger airspace which results in a TA being
annunciated is the caution area. Figure 1--3 contrasts the airspace covered by the
two types of advisories.
The onboard equipment listed below must be linked to the TCAS function as shown
in Figure 1--4.
• Mode S transponder with associated antennas
• Radio altimeter
• Air Data Computer (ADC) (digital or analog). If an ADC does not support vertical
speed rate data, the static line can be run directly into the Thales VSI/TRA.
• ATC/TCAS control panel. A separate control panel is not the only method of
control for the TCAS. Other components, such as a Radio Management Unit
(RMU) can be used.
• Omnidirectional antenna. The TCAS function accepts two types of bottom
antennas: A standard directional antenna or an optional ATC -- type
omnidirectional antenna. If an omnidirectional antenna is installed, it must be
supplie d by the installe r. If a directional antenna is installed at both top and
bottom antenna locations, a bottom omnidirectional antenna is not needed.