Fmz-800 Fliqht Management System - Honeywell SPZ-8000 Maintenance Manual

4.
FMZ-800 Fliqht Management System
A. General
The flight management system (FMS) is designed as a federated system,
where there are independent components but each component performs a
system function. The FMS is comprised of three basic components. The
first component of the system is the CD-81O Control Display Unit (CDU).
The other two components are the NZ-920 Navigation Computer and the
PZ-800 Performance Computer. Since each computer is a self-contained
unit, NAV only or performance only systems are possible. The key to the
federated approach is
to keep the navigation and performance functions as
separate and independent as possible, and yet allow for their
coexistence.
Some
performance calculations, however, utilize navigation data and some
navigation displays include performance data.
The flight plan data and
other joint use information are shared between the navigation and
performance computers on the ASCB; however, the majority of the NAV-PERF
integration is through the CDU. The CDU can be driven from the
navigation computer for NAV, or predominately NAV display pages. The CDU
is then driven from the performance computer for PERF pages. This keeps
the computers as independent as possible. It is a design requirement to
keep aircraft variable data in the performance computer. The
architecture of the NAV, performance, and CDU integration is shown in
Figure 262.
The CDU provides the primary means for pilot input into the system. It
also provides an important output display for the navigation and
performance computers. The CDU utilizes a full alphanumeric keyboard,
with four line selection keys on either side of the CRT. Several
function keys are provided to allow direct access to specific display
pages. Annunciators are built into the top of the unit to advise the
pilot of the system's status. The CDU sends ASCII characters
simultaneously to both the navigation
and performance computers.
The NZ-920 Navigation Computer is the component in the FMS, which
provides both lateral and vertical navigation guidance. The database
inside the NZ-920 is used for storage of waypoints, navaids, routes,
airports, and other NAV data for easy access by the pilot. The NZ-920
can interface with five long range sensors; three via ARINC 429 buses and
two over the ASCB bus. Each navigation computer can also connect to dual
Proline 2 429 scanning DME receivers and VOR/ILS receivers. The
interface to the air data, EFIS, performance computer and autopilot is
over the avionics standard communications bus(ASCB). Flight Plans are
also transferred between navigation computers over the ASCB while the
link to the CDU is over a RS-422 private-line interface. To provide
high-accuracy long range navigation, the navigation computer is designed
to connect to IRS, GPS, Omega/VLF sensors plus VOR/DME. With links to
the on-board navigation sensors, the navigation computer develops an FMS
position based on a blend or mix of the sensors. The FMS does not
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Page 298.149
Apr 15/93
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