User's Manual

SYSTEM DESCRIPTION AND INSTALLATION MANUAL
T
3
CAS/Part No.9005000
4. Component Descriptions
A. T
3
CAS Computer Unit
The TCAS function contains the RF transmitter and the receivers necessary to
interrogate and receive replies from other transponder equipped aircraft. Surveillance and
collision avoidance algorithms determine whether an intruder aircraft should be
considered a threat and then determine the appropriate vertical response to avoid a
midair or near midair collision. In addition, output data is provided to drive displays that
inform the flight crew what action to take or avoid.
The TCAS function also provides an interface to the onboard Mode S transponder in
order to communicate with other TCAS ll equipped aircraft in the airspace.
The TAWS/RWS function consists primarily of the Ground Collision Avoidance Module
(GCAM). The GCAM contains the core TAWS/Windshear algorithms which utilize A/C
state data, performance database variables and Terrain/Airport database information to
calculate required TAWS/Windshear alarms, build a terrain display buffer, and then pass
the data back to the platform. The resulting terrain information is then output to ARINC
708A compatible weather radar or EFIS displays.
The Transponder function supplies surveillance functions to both ground-based and
airborne interrogators, as well as communication functions to various onboard systems.
The transponder contains data link functions that allow it to function as part of the
Aeronautical Telecommunications Network (ATN). The data link functions allow
communication with a Communication Management Unit (CMU) via a Mode S Airborne
Data Link Processor (ADLP). The transponder also has Mode S specific functions that
are dedicated links to onboard systems.
The T
3
CAS CU also provides past and present LRU and system status through the front
panel mounted TEST switch and PASS/FAIL annunciators. Software updates can be
incorporated into the computer by Compact Flash Card an ARINC 615A data loader port
through either the connector mounted on the front panel of the computer or the port
provided on the LRU rear connector.
Figure 1-8 shows a graphical view of the T3CAS Computer Unit.
Table 1-15 provides the leading particulars.
Table 1-16 provides the DO-160E Categories.
NOTE:
The RWS function is not applicable to Part Numbers 9005000-10000, -10101, -10202, -
10204, or -11203.
Pub. No. 8600200-001, Revision 004
34-45-29
1-47
04 Nov 2014
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