User's Manual Part 2

T
2
CAS / Part No. 9000000
SYSTEM DESCRIPTION AND INSTALLATION MANUAL
34-43-20
15 Feb 2003
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6--1
FAULT ISOLATION
1. General
The T
2
CAS Traf fic and Terrain Collision Avoidance System has three optional procedures for
fault detection and isolation to the LRU level. The first option uses the aircraft CMC or central
fault display system (CFDS) if the aircraft is equipped with a n onboard maintenance system.
The second option uses a digital interface between the T
2
CAS Computer Unit and the display
system (Weather Radar, EFIS, or multifunction display for TAWS/RWS and VSI/TRA flat panel
display or EFIS for TCAS). The third option uses the annunciators located on the front panel
of the computer unit. The annunciators are activated by a self--test function within the T
2
CAS
Computer Unit. Select the procedural option for fault isolation from Fault Isolation paragraph
3 (Procedure), which is applicable to the type of aircraft and the equipment installed.
2. Equipment and Materials
NOTE: Equivalent alternatives are permitted for equipment in this list.
Digital Multimeter -- Fluke Model 29, John Fluke Mfg Co. Inc., Everett, WA
3. Procedure
A. CMC or CFDS
Fault information can be displayed from an onboard maintenance system when the
aircraft is so equipped. Fault data is accessible only when the aircraft is on the ground.
Faults that occur at any time, on the ground or while airborne, are stored in fault memory
and reported to the CMC or CFDS. All displayed information is in the English language
with abbreviated terms used only as necessary. Refer to the appropriate CMC or CFDS
support manual for fault retrieval procedures.
B. Flight Deck Initiated Self--Test/Fault Display Systems
(1) TCAS
The TCAS display system can be u sed to display system status and fail messages in
the Flight Deck, making it more convenient to use than the computer unit front panel
annunciators for a quick checkout of the TCAS system. In contrast with the computer
unit self--test, which records and stores faults from previous flights, the display
system test shows o nly current status and failure data.
To access the Flight Deck display test modes, perform the following procedures:
NOTES:
1. Fault detection with diagnostics can only be done on the ground. The pilot
has the option to do a pass/fail test while airborne if this feature is not
inhibited.