User's Manual
SYSTEM DESCRIPTION AND INSTALLATION MANUAL
TCAS 3000 Traffic Alert and Collision Avoidance System
34−43−23
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Page 6−21
15 Dec 2005
Table 6−4 lists the functions of the computer unit’s status annunciators and the
corresponding troubleshooting actions. If the annunciators indicate an antenna problem,
the antenna connections should be checked by measuring the antenna resistance values
at the computer unit mounting tray. The resistance values listed in Table 6−5 are
measured between the center conductor and shield on each LTP and LMP antenna
connector.
Table 6−3. Computer Unit Self−Test Execution
Test Sequence Activation Test Indications
Power On Self−Test Self−Test is activated with
each application of system
power
No indication unless a fault is detected.
System status/fault data is stored in memory
for 10 consecutive flight legs. Data can be
recalled by doing the commanded self−test on
the ground.
Continuous Self−Test Executed automatically as
part of normal TCAS inflight
operation
No indication unless a fault is detected.
System status/fault data is stored in memory
for 10 consecutive flight legs. Data can be
recalled by doing the commanded self−test on
the ground.
Commanded
Self−Test
Push the front panel PUSH
TO TEST button
• All front panel lamps come on during a
3−second lamp test.
• If the TCAS is operational, the TCAS PASS
green lamp comes on for a 10−second
display period and then goes off.
• If the TCAS is not operational, one or more
red fault lamps come on for a 10−second
display period. Refer to Table 6−4 for
corrective action.
Push the PUSH TO TEST
button again before the
previous 10−second display
period has elapsed
• Previous fault display is aborted
• All lamps come on during a 1−second lamp
test
• Status/fault data recorded during the
preceding flight leg is displayed for
10−seconds.
Push the PUSH TO TEST
button before the end of each
succeeding display period
• Status/fault data recorded during a total of
10 flight legs (maximum) is displayed
• When data from the earliest recorded flight
leg has been displayed, all lamps flash at a
2.5−Hz rate for 3−seconds if the PUSH TO
TEST button is pushed. This indicates the
end of recorded test data.