The attitude display on the EADI will
power up to the previously selected
Heading pushbutton selector switch. The
heading pushbutton selector switch, placarded HDG, is
used to select whether gyro-magnetic compass system #
1 or # 2 will supply heading information to the respective
EHSI. Each depression of the switch will cause the
display on the EHSI to alternate between MAG1 and
MAG2, unless the SLAVE/FREE switch is set to FREE,
then DG1 or DG2 will be displayed.
VOR/localizer pushbutton selector switch.
The VOR/localizer pushbutton selector switch, placarded
V/L, is used to select which VHF navigation receiver will
provide information to the respective EFIS. Each
depression of the switch alternates the navigation source
display on the EHSI between VOR1 or VOR2, or ILS1 or
ILS2, depending upon whether a VOR or localizer
frequency has been selected on the respective VHF
navigation receiver control panel.
The VOR/localizer switch may be used to
activate the preview mode on the EHSI if:
INS is displayed on the EHSI as the navigation
LNAV flight director mode annunciator is
displayed on the EADI
System is powered-up using the primary on-side
VHF navigation receiver.
The preview mode may be cancelled by
depressing the V/L switch.
INS/TACAN pushbutton selector switch.
The inertial navigation system/TACAN pushbutton
selector switch, placarded INS/TCN, is used to select
whether the INS or TACAN will provide information to
the EFIS. Each depression of the switch will alternate
the navigation source annunciator on the EHSI between
INS and TCN.
Double-needle pointer bearing source
selector switch. The double-needle pointer bearing
source selector switch, located on the lower right side of
the display controller, is used to select which navigation
information sources will provide information to the
double-needle bearing pointer.
OFF. Removes double-needle
pointer from the EHSI.
VOR2. Double-needle pointer receives
bearing information from # 2 VHF navigation receiver.
receives bearing information from ADF navigation
receives bearing information from the inertial navigation
receives bearing information from TACAN navigation
Weather radar dim control. Control of the
intensity of the weather radar display on the EHSI is
accomplished by a control knob placarded WX DIM,
which is an inner concentric knob with the HSI DIM
The WX DIM control dims only the raster on the
EHSI which contains the weather radar information. If
the EHSI is in the composite mode with the EADI, the
WX DIM control is used to dim the attitude sphere.
EHSI dim control. Control of the intensity
of the raster and stroke writing on the EHSI is
accomplished by a control knob placarded HSI DIM,
which is an outer concentric knob with the WX DIM
knob. Turning the knob counterclockwise to the OFF
position will cause the EHSI to become blank and the
composite mode to be displayed on the EADI.
Decision height setting control and EFIS
Decision height setting control. The
decision height setting control, placarded DH/TEST, is
an inner concentric knob with the ADI DIM knob.
Rotating the DH knob allows setting the decision height
display on the EADI in 10-foot increments from 200 to
990 feet, and in 5 foot increments from 0 to 200 feet. By
rotating the DH knob completely counterclockwise to the
OFF position, the decision height display may be
removed from the EADI.
EFIS test switch. Depressing the
EFIS test switch, placarded TEST, will cause the EFIS
displays to enter a test mode. In the test mode, flags
and cautions are presented along with a test of the radio
altimeter. Observe the following after depressing the
A complete test of the EFIS is only functional on the
ground. Radio altimeter test is functional at all times
except during glideslope CAP/ TRK.
Course select, heading select, DH set, DME
distance, and GSPD/TTG digital displays are replaced
by amber dashes.
ATT and HDG displays are flagged.