(d) CDU BAT annunciator is illuminated.
Operation on battery is an indication that there may
be no aircraft power to blower motor with resultant loss
of cooling. The INS can operate only a limited time
(normally 15 minutes) on battery power before a low
corrective action must be taken.
CDU BAT indicator will illuminate
for 12 seconds in alignment State 8
(about 5 minutes after turn-on).
This is normal and indicates a
battery test is in progress. No
corrective action is required.
During ground operation, it is
recommended that operation on
To determine corrective action:
(Monitor CDU displays while rotating the CDU
If displays are frozen (do not
change while data selector is being
rotated), problem is normally in the
b. If displays respond normally to the
normally absence of 11 5V AC
power to INS.
(e) For corrective action: Check to assure proper
settings of the following switches and circuit breakers
essential to INS operation:
Overhead circuit breaker panel (fig. 2-6)
- Circuit breakers in:
(1) AVIONICS MASTER CONTR
(2) INS CONTROL
(3) AVIONICS MASTER PWR No. 1
(4) AVIONICS MASTER PWR No. 2
Overhead control panel (fig. 2-13):
INVERTER No. 1 or INVERTER No 2 switch - ON
Mission control panel (fig. 4-1):
(1) #1 INV or #2 INV switch - ON.
(2) Bus cross tie switch - ON/AUTO.
Mission AC/DC Power Cabinet (fig. 2-
29): INS AC PWR circuit breaker - In.
extinguish after above corrective
action. If it remains illuminated, INS
will eventually shut down when
approximately 19VDC. Flight crew
should prepare for shutdown.
(3) Malfunction indications and procedures:
Table 3-3 details the procedure for a Malfunction Code
Check. Table 3-4 lists a number of malfunction
indications which occur under given modes of operation.
Table 3-5 details, action codes and recommended
action. Follow procedure given. Table 3-6 lists failed
test symptoms by malfunction codes and lists codes for
GLOBAL POSITIONING SYSTEM (AN/ASN-
Description. Complete provisions are installed
for a global positioning system (GPS). The GPS is used
to provide updated position information to the inertial
navigation system. The GPS system consists of a
control/display unit, receiver, observer headset and
GPS key panel, antenna electronics unit, and an
control/display unit (fig. 3-23A), located on the
electronics rack located in the cabin, accomplishes all
display and control functions necessary for the operation
of the GPS receiver.
(2) Observer Headset and GPS Key Panel.
The observer headset and GPS key panel (fig. 3-23B),
located on the electronics rack in the cabin, contains a
headset connector and GPS key and loading controls.