The diagnostics page consists of MFD status
information shown as a result of a Built-In-Test (BIT).
The diagnostic display page is only active while the
aircraft is on the ground and the Weight On Wheels
(WOW) discrete is set.
Perform the following procedures to select the
MFD status page.
1. Press the MFD test button on the
2. Press the ARC button on the
control panel to exit diagnostics.
(e) Decision Height (DH) Setting. The
DH knob rotates and has a center push button. The
DH SET knob is used to set the decision height.
Clockwise rotation increases the decision height. The
decision height is displayed in green following the
letters DH in the lower right corner of the ADI. When
the radio altitude is at or below the DH setting, the
yellow letters DH appear in the right center portion of
the ADI or PFD display and a Minimum aural
annunciation is sounded. Once the DH annunciation
appears, it is removed from the display when the radio
altitude climbs at least 25 feet above the decision
height. If the radio altimeter system fails, the decision
height annunciator is removed and the radio altitude
(f) Radio Altitude Test. The center push
button on the DH SET knob setting is a radio altitude
test button. Pushing the test button causes the radio
altimeter to go into test. While the radio altimeter is in
test, the digital readout remains displayed, even when
the radio altimeter validity is flagged.
(g) Course Source Selector. The blind
course select knob is a dual concentric knob with a
center push button. The outside knob selects the
active course sources. The selections are FMS or
VOR. The selector switch is knob that when rotated
cycles between the sources. Used in conjunction with
the CRS 1/2 button, the Nav sources are switched
between all navigation sources (i.e., FMS 1/FMS 2 or
(h) Course Selector. The inner knob on
the Course Source Control selects the desired course
for the active course source. When the knob is moved
slowly, a single click will result in a 1° course change.
If the knob is rotated quickly, the course setting
changes numerous degrees per click.
If the OBS / LEG switch is in the OBS mode, the
pilots course setting knob will control the course for
the KLN 90B. The bottom MFD on the pilots side
provides the selected course to the KLN 90B when it is
in the OBS mode.
(i) Course Sync Button. The center
push button on the course source control is a CRS
sync button. Pressing the CRS sync (Direct-To)
button for a VOR (VHF Omni Range) course source
sets the active sources course to the sources
(j) CRS 1/2 Button. The CRS 1/2 button
toggles the selected navigation course (selected by
the Course Source Control) between #1 and #2.
(k) ARC Button. The center push button
on the mode selector is an ARC button. Pressing the
ARC button toggles the EHSI display as follows:
1. HSI Mode. Full 360 compass
rose or HSI ARC 80 compass
2. MAP Mode. Map 80 arc or Map
full 360 compass.
(l) Range Selector. The inner knob on
the mode selector selects the range for displays where
range is applicable. Available ranges are 2.5, 5, 10,
20, 40, 80, 160, 320, and 640 nm. Range information
is stored in the control panel and defaults to the last
selected value at power up.
(m) MODE Selector. The mode select
knob is a dual concentric knob with a center push
button. The outer knob allows you to select between
HSI and map modes.
(n) ADI / PFD Button. The ADI / PFD
button on the display control panel toggles the display
between the basic EADI display and the Primary Flight
bearing (BRG) button selects the navigation source to
be displayed on the EHSI bearing pointer. The aircraft
bearing selections are OFF, FMS 1, FMS 2, VOR 1,
VOR 2, ADF 1, and ADF 2. If a VOR frequency is
tuned on the pilots NAV receiver, the source becomes
(p) Heading (HDG) Selector. The inner
knob of the data selector is used to position the
heading bug. When the heading knob is moved
slowly, a single click results in one degree heading
changes. If the knob is rotated quickly, the heading
setting changes numerous degrees per click.