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--34
(5) Self --Test Function
(a) TCAS and TAWS/RWS Maintenance Self--Test
By momentarily pushing the TEST switch on the front panel of the T
2
CAS
Computer Unit, maintenance personnel can display fault data for the current and
preceding flight legs. When TEST is initially activated, all annunciators (pass/fail
lamps on front of unit) are ON for a 3--second lamp test, then current fault data is
displayed for 10 seconds. If no further activations of the TEST switch are made,
the LRU display cycle is terminated at the end of the 10--second fault display
period, and all annunciators are extinguished.
If during the 10--second fault display period, the TEST button is activated again,
the fault display period is aborted, a 2--second lamp test cycle is done, and the
fault data recorded for the preceding flight leg is displayed for 10 seconds. This
procedure can be repeated up to 10 times to obtain recorded data from the
previous 10 flight legs. If the TEST button is not activated again during the fault
display period, the fault display cycle is terminated at the end of the 10--second
fault display period and all annunciators are extinguished. If an attempt is made
to display fault data for the preceding flight leg when the tenth preceding flight
leg fault data is displayed, all annunciators flash for a 3--second period at a
2.5--Hz rate, after which all annunciators are extinguished.
When less than 10 flight legs have been flown since the T
2
CAS Computer Unit
was shop tested and recertified, less than 10 previous flight legs of recorded
fault data may be available for display. In this case, if an attempt is made to
display fault data for the preceding flight leg when the earliest flight leg is
displayed, all annunciators flash for 3 seconds at a 2.5-- Hz rate and then all
annunciators are extinguished.
The TCAS PASS, TCAS FAIL, and TAWS Pass/Fail status annunciators indicate
the status o f the T
2
CAS Computer Unit only. All other annunciators reflect the
condition of the respective sub--system.
(b) TCAS Self --Test
The T
2
CAS TCAS self--test is initiated from a self--test button on the
TCAS/MODE S control panel. The T
2
CAS TCAS self-- test may also be initiated
from the Central Maintenance Computer.
(c) TAWS/RWS/GPS Self -- test
The T
2
CAS TAWS/RWS/GPS self -- test is initiated from a self--test discrete input
interface. The TAWS/RWS/GPS self -- test discrete is further defined in the ASDB.
The T
2
CAS TAWS/RWS/GPS self-- test may also be initiated from the Central
Maintenance Computer.