Users Manual

ALL
EFFECTIVITY
© Honeywell International Inc. Do not copy without express permission of Honeywell.
Page 2-41
22 Apr 2019
23-15-49
SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
ASPIRE-400
(1) The ACARS Air-Ground Protocol (AAP) is Inmarsat's bespoke transport layer protocol
used for tunneling of ACARS data over SwiftBroadband network. AAP version 2 defined
in SDM Volume 3 Chapter 4 and in Iris Precursor System Design Document is to be
implemented in the SDU by the Aircraft Data Link Gateway function (ADGW). This
gateway:
(a) Requires VPN authentication by the underlying Air Security Gateway function
(ASGW) and the related security smart card.
(b) Provides for connection of ACARS services.
(c) Provides Location tracking services.
(d) Provides time-stamping required for the mandatory service performance
monitoring at the service provider level.
(e) Provides independent link availability monitoring (keep-alives).
(2) Terminology aligns to the version2 terminology:
(a) ADGW Aircraft Datalink Gateway is equivalent to AAGW ACARS aircraft
Gateway.
(3) GDGW Ground Datalink Gateway is equivalent to AGGW ACARS Ground Gateway.
17. Aircraft Information (TASK 23-15-49)
A. Time and Date
(1) The SDU uses Time and Date for:
(a) Timestamping messages to the CFDS
(b) Timestamping log entries
(c) Assessing validity of PIMBIT test frequencies.
(2) On-start up the internal clock is set to a default time and date. Thus, prior to
synchronizing to an external source it only represents a time relative to start up.
(3) The SDU also stores snapshots of the Network Date for:
(a) Assessing validity of PIMBIT test frequencies
(b) Checking expiration of temporary license keys.
(4) On start-up, the ACD sets its internal time and date to a default of 2016-01-01, 0 hours, 0
minutes, 0 seconds.
(5) The ACD prohibits timestamping and logs "aging out operations using absolute time and
date until the internal time and date has synchronized with either aircraft or network time
and date.
(6) The ACD synchronizes its internal time and date to the first source that provides it:
(a) The ORT identified time and date source, OR
(b) Time received from the Inmarsat satellite SBB system information.
(7) Once the ACD has selected a source and synchronized its internal time and date to that
source, the ACD continues to synchronize its internal time and date to that source until
the next SDU restart.
(8) The ACD distributes its internal time and date to the AP Processor at minimum at startup
or when a resynchronization occurs.
DRAFT
3rd rvw Draft as of:
29 January, 2020