User's Manual Part 1

T
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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--65
3
During T
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CAS computer unit self-- test, an aural advisory confirms proper
operation of the aural advisory system by annunciating the message “TCAS
TEST”. The aural advisory system annunciates the pass/fail status of any
monitored functions with the messages “TCAS TEST PASS” and “TCAS
TEST FAIL”, respectively.
4
An aural advisory tone will precede each aural advisory when the audio tone
enable program pin has been activated.
5
T
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CAS computer unit TCAS aural alerts are inhibited when the advisory
inhibit discrete input No. 4 is grounded. An aural advisory in progress is
disabled after the grounding of advisory inhibit discrete No. 4. The truncated
message is annunciated in its entirety once the inhibit discrete has been
released. This capability is used to defer all advisory (TA and RA), aural
alert, and visual alert outputs until another, higher priority
announcement/alert is completed.
6
Increases and decreases in the threat level are aurally annunciated.
However, decreases in threat level are annunciated once and are not
preceded by setting the audio tone discrete. For example, a vertical speed
restriction following a climb RA is annunciated once.
(b) Traffic Advisory (TA) Message
The traffic advisory aural alert, TRAFFIC -- TRAFFIC is spoken once, and then
inhibited until the next TA occurs. This alert occurs when TCAS predicts an
intruder will enter the collision area within 20 to 48 seconds. Simultaneously, the
TCAS traffic display shows the location of the intruder.
(c) Resolutio n Advisory (RA) Messages
Resolution advisories indicate evasive vertical maneuvers calculated to increase
separation between the TCAS aircraft and the intruder (corrective advisory), or to
indicate certain changes in vertical speed are not recommended (preventive).
Resolu tion advisory messages made up of a single word are repeated three
times; longer messages are repeated twice.
RAs are annunciated on the T
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CAS computer unit using the voice messages
listed below as determined by Collision Avoidance System (CAS) data. The
following messages will not immediately follow another message from this
paragraph if it causes a reversal of sense. For example, a “CLIMB, CLIMB”
message cannot immediately follow a :”DESCEND, DESCEND” message.
1
“CLIMB, CLIMB”: Climb at the rate shown on the VSI or other suitable
indicator.
2
“DESCEND, DESCEND”: Descend at the rate shown on the VSI or other
suitable indicator.