User's Manual

SYSTEM DESCRIPTION AND INSTALLATION MANUAL
T
3
CAS/Part No.9005000
Each of the military radio altimeter types provide two outputs that are
connected to the T
3
CAS CU input pins. The two altimeter outputs are
the Analog Data Output and Analog Data Reliability signal. The
T
3
CAS CU uses the Data Reliability signal in conjunction with the
Analog Data Output to determine radio altimeter failures.
A condition exists for several military radio altimeters known as Out-
of-Track. This condition occurs when the radio altimeter has not
failed and the altimeter is not reading a valid altitude. Altitude data
for an Out-of-Track condition should be considered invalid and not
used.
The digital radio altimeter interface accepts inputs from an ARINC
707 radio altimeter on ARINC 429 low-speed input busses.
2 Voice Audio Outputs
The T
3
CAS contains two analog audio outputs that provide
TAWS/RWS and TCAS aural advisories. The 8-ohm output has the
capability to supply up to 4 Watts RMS into a speaker. The 600-ohm
output has the capability to supply up to 80 milliwatts RMS into an
audio distribution system.
3 Onboard Maintenance System Interface
The TCAS function contains a set of ARINC 429 low-speed busses
for communication with an onboard maintenance system (1 input, 1
output). The input RBP-6G/6H is shared with the TAWS functionality.
The output is RBP-6E/6F. The unit interfaces with all major airframe
manufacturers maintenance computer systems. Since the
maintenance computer protocol for each airframe manufacturer is
different, the TCAS function automatically detects the type of
airframe from the data received from the maintenance computer and
sets its protocol accordingly. The TCAS OMS interface supports all
Boeing and Airbus maintenance systems.
The TAWS/RWS function contains an interface to an onboard
maintenance system that allows fault and diagnostic information to
be retrieved. The ARINC 429 input is shared with TCAS on RBP-
6G/6H. The ARINC 429 output bus, RTP-8A/8B contains OMS data;
however, the output is shared with other systems and contains
additional data. The OMS has capability to display BITE fault log
information over the display device. Current faults and faults from
previous flight legs may be displayed. In addition, information such
as software part numbers may be displayed. The OMS can be used
to initiate TCAS, TAWS/RWS and XPDR system tests.
The XPDR function contains an interface to an onboard maintenance
system that allows fault and diagnostic information to be retrieved.
The ARINC 429 input is RTP-5G/5H. The ARINC 429 output bus,
RTP-8E/8F contains OMS data. The OMS can be used to initiate
TCAS, TAWS/RWS and XPDR system tests.
Pub. No. 8600200-001, Revision 004
34-45-29
1-54
04 Nov 2014
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