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SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
MCS--4200/7200 Multi--Channel SATCOM System
(b) Once a failure is reported in the normal mode, the failure remains in the report
for that entire flight, regardless of whether the failure is cleared. As new failures
are reported, they are added to the beginning of the report (i.e., the report is in
reverse chronological order, bearing in mind the CFDS considers the time of the
failure to be the time it is first reported on this flight leg rather than when it first
occurs).
(c) In addition to latching the failures, the contents of the normal mode report
depend on the failure class and when it occurs in relationship to other failures
against the same LRU. Level I failures against the same LRU reported in the
normal mode are not to be transmitted more than once unless they are an upper
class and the upper class failure occurs after the lower class failure(s). Once a
report is sent to the CFDIU during the normal mode for the current flight, the
SDU does not change the content or order except to add new failure messages,
as appropriate to the beginning of the report.
(d) The McDonnell Douglas CFDIU does not decode the normal mode report until
the CFDIU detects an increase in the block word count. However, unlike the
Airbus CFDIU, the McDonnell Douglas CFDIU decodes the entire report. After
sending an All Call DC2 command for a new flight leg, the Airbus CFDIU delays
processing the normal mode report for about 30 seconds before regarding the
report as pertaining to the new flight leg.
(e) The SDU transmits the names of the installed LRUs, as determined by the
system configuration pin settings, along with their associated part/serial
numbers. At the end of this LRU transmission, the SDU transmits the ORT
identification with a modification status. The LRU names can be transmitted in
any order. Transmission of an HPA LRU part/serial number uses the same
criteria as the display of HPA data.
(5) Interactive Mode
(a) The CFDIU supplies for two-way communication between the SCDU and the
SDU, which is referred to as the interactive mode. When the SDU operates in the
interactive mode, it is responsible for all information displayed on the CFDS
maintenance pages, with exception of the scratchpad. The SDU enters the
interactive mode upon receiving an ENQ command from the CFDIU when the
aircraft is on the ground.
D. Central Aircraft Information and Maintenance System
(1) The central aircraft information and maintenance system (CAIMS) is a distributive
maintenance system where each member system performs its own built--in test (BIT)
and stores its own faults. Also, each system supplies real--time status information on
the health of each of its LRUs and their interfaces. The member systems support
CAIMS during normal operation and during on--ground maintenance.
Honeywell International Inc. Do not copy without express permission of Honeywell.
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Page 6--94
15 Jul 2006
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