BOMBARDIER Challenger 601-3A CL-600-2B16 Pilot Training Manual page 435

R E M OT E AU X I L I A RY BAT T E RY / A P U
BATT/CHARGER FAIL annunciator panel
provide backup battery/charger status annun-
ciations. Located on the copilot's side console,
an amber BATT/CHARGER FAIL IRS 1, IRS
2, or IRS 3 (optional) annunciation indicates
that the backup battery is not being charged.
Mode Select Unit
A six-annunciator MSU controls the operation
of each IRU. A four-position mode select
switch controls the functions of the MSU.
Each annunciator indicates an IRS status.
The MSU functions in the following four
modes:
• Align
• Navigation (NAV)
• Attitude (ATT)
• Test
ALIGN Mode
Rotating the MSU mode select switch to
ALIGN turns on the IRU, illuminates the
ALIGN annunciator, and selects the align
mode (Figure16-21). During normal opera-
tions between 70° North and 70° South lati-
tudes, the alignment time varies from 2.5 to
10 minutes. If attempting alignment above
70° North or below 70° South latitude, align-
ment accuracy may be downgraded due to the
low earth-rates measured at these coordinates.
CAUTION
Navigation performance may be de-
graded if the IRU is aligned at lati-
tudes above 70°.
Before providing valid navigation outputs,
the IRS must be initialized with present po-
sition latitude and longitude data. The data can
be entered from either the ISDU or the FMS
CL-600-2B16 PILOT TRAINING MANUAL
CDUs. The primary method of initialization
consists of using the FMS CDU. Both the lat-
itude and longitude coordinates must be en-
tered manually or selecting an airport identifier
waypoint. Prior to entering the NAV mode,
the ALIGN mode accepts any changes to the
initialization data without delaying the align-
ment time.
The ALIGN annunciator flashes and the
FAULT annunciator illuminates if the system
detects an incorrect aircraft position input, an
excessive aircraft movement, or an internal
self-test circuit error. When the system com-
pletes the alignment process, the ALIGN an-
nunciator extinguishes and the NAV RDY
annunciator illuminates.
Without the present position data, the IRS re-
mains in the alignment mode when setting the
MSU mode select switch to NAV. During the
alignment mode, the IRU aligns the reference
axes to the local vertical and computes head-
ing and latitude by measuring the three-axis
earth-rate components. The IRU also performs
a reasonableness test that compares the entered
present position and the last known position
prior to shutdown.
NAV Mode
After alignment completion, setting the mode
selector switch to the NAV position immedi-
ately switches the IRU to the navigation mode
(Figure 16-21). Without alignment completion,
the IRU remains in the alignment mode until
the alignment completes and then automati-
cally switches to the navigation mode. When
in the navigation mode, the ALIGN and NAV
RDY annunciations extinguish, and the IRU
begins sending data to the other systems.
FOR TRAINING PURPOSES ONLY
FlightSafety Canada
CAUTION
The IRS will not complete align-
ment if the aircraft is moved. Make
sure that the aircraft is stationary
during alignment.
L t é e
L t d .
CL 601-3A/R 16-23