Learjet 60 - Standby Attitude Indicator

Learjet 60

Pilot's
Manual
red
OFF Rag
will
appear if the gyro is caged, power is not applied or
was lost, or the gyro becomes inoperative . The standby attitude indica-
tor is powered by 28 VDC supplied by EMER BAT 1 . The standby atti-
tude indicator is used to cross check the pilot and
copilot attitude
displays and serves as a back up unit in the
event both AHS 1 and
AHS 2 become
inoperative .
THREE-INCH INDICATOR
STANDBY ATTITUDE INDICATOR
Figure 5-9
An optional J .E .T .
ADI-331
standby attitude indicator may be installed
in place of the standard
2-inch
indicator . It is a 3-inch, self-contained
gyro powered by 28 VDC supplied from EMER BAT 1 . This unit incor-
porates all of the features described
far
the
2-inch unit as
well as
cross-
pointers to show deviation from glideslope
and localizes beams . If the
signal becomes invalid, GS
and/or LOC flags will come into view and
the associated
crosspointer(s) will be stowed . The crosspointers and
flags are active only when an ILS frequency is tuned on
the #1 NAV re-
ceiver . An inclinometer, on the front of the instrument,
shows aircraft
slip/skid
information .
The ADI-331 installation W designed to provide
attitude,
glideslope,
and localizes information independent
of
the
normal electrical system
.
In the event
the normal
electrical system
fails,
EMER BAT 1 will supply
28 VDC to power the standby attitude indicator,
and
EMER BAT 2 or
EMER BAT 1 will supply 28 VDC to power the #1 NAV receiver and the
#1 Radio Tuning Unit (RTU),
Although the #1 RTU will be operative
under these conditions,
its only meaningful function will be to tune the
#1
NAV receiver to an ILS frequency since the COM, ADF, and ATC
equipment will be inoperative .
PM-123

5- 31
Change 4