Honeywell SPZ-8000 - Mode Select Unit (MSU; A-2 Six-Annunciator MSU

SPZ--8000 Digital Integrated Flight Control System
A28--1146--055
REV 2
LASEREF
R
II/III Inertial Reference System (IRS)
A--4
MODE SELECT UNIT (MSU)
The MSU, shown in Figure A--2, is used to make IRU mode selection,
display IRS status, and initiate the remote test. As many as three MSUs
can be installed. Refer to Figure A--2 for the locations of annunciators
and controls described below.
Six--Annunciator MSU
Figure A--2
The MSU consists of a rotary mode select switch, a test switch, and six
annunciators.
The four--position mode select switch selects basic modes and
submodes of operation.
Modes and submodes are selected by setting the MSU mode select
switch as follows:
D OFF--To--ALIGN -- The IRU enters the power--on/built--in test
equipment (BITE) submode. When BITE is complete, the IRU
enters the alignment (ALIGN) mode. The IRU remains in the ALIGN
mode until the mode select switch is set to OFF, NAV, or ATT. The
NAV RDY annunciator lights when alignment is complete.
D OFF--To--NAV -- The IRU enters the power--on/BITE submode NAV.
When BITE is complete, the IRU enters the ALIGN mode. When the
alignment is complete, the IRU enters the NAV mode.
D AL I G N-- To-- NAV -- The IRU enters the NAV mode from the ALIGN
mode when the alignment is complete.
D NAV--To--ALIGN -- The IRU enters the ALIGN downmode from the
NAV mode.