TM 1-1510-225-10
3A-106
a. Update card – Remove.
b. System – Turn OFF.
c. Update card – Verify and re-insert into
CDU.
d. System – Turn ON and retry update
using update procedure.
3A-29. GYRO MAGNETIC COMPASS SYSTEM.
a. Description.
Two
identical
compass
systems provide accurate directional information for
the aircraft at all latitudes of the earth. For heading
reference,
two
modes
of
operation
are
used:
directional gyro (FREE) mode, or slaved (SLAVE)
mode. In areas where magnetic references are
reliable, the system is operated in the SLAVE mode.
In this mode, the directional gyro is slaved to the
magnetic flux valve that supplies magnetic reference
for correction of the apparent drift of the gyro. In
FREE mode, the system is operated as a free gyro. In
this mode, latitude corrections are manually introduced
using the INCREASE/ DECREASE switches. The
slave/free mode is selected as desired using the
SLAVE/FREE switches. Both compass systems (No.
1 and No. 2) are ac power dependent, and are
powered by the selected inverter. Gyro compass 1
provides heading information for the pilot's HSI and
copilot's RMI. Gyro compass 2 serves the copilot’s
HSI and the pilot's RMI.
b. Controls. The controls for the number 1
system are located to the left of the pilot’s RMI and is
controlled by two switches. The top switch is
placarded SLV and FREE and selects the mode of
operation. The bottom switch is Counter Clockwise,
placarded (CCW) and Clockwise (CW) and is used to
adjust the gyrocompass. A glass window with a
needle inside is placarded
– and + indicates
adjustment.
c. Heading Miscompare Indicator. The EFIS
EHSI will indicate which mode the directional gyro is
operating in (SLAVE or FREE) and which system is
providing the heading information, (No 1 or No 2). The
yellow heading miscompare needle will appear
anytime the No. 1 and No 2 heading differ by more
than 6°.
Section IV. RADAR AND TRANSPONDER
3A-30. RADAR AND TRANSPONDER EQUIPMENT
GROUP DESCRIPTION.
The radar and transponder group consists of a
weather radar, lightning sensor system, ground
proximity altitude advisory system and transponder.
The transponder and radar group includes an
identification, position, emergency tracking system,
and a radar and lightning sensor system to locate
potentially dangerous weather areas.
3A-31. WEATHER RADAR SYSTEM (RDS 84VP).
The weather radar system is a light weight,
X-band digital radar with alphanumerics designed for
weather detection and analysis and ground mapping.
The radar system is controlled from the radar control
panel,
Figure
3A-65,
located
on
the
pedestal
extension, Figure 2-11. Radar information is displayed
on the pilot's and copilot's electronic horizontal
situation indicator (EHSI) and on the multifunction
display (MFD), Figure 3A -66.
