deviation is sent to the flight director when it is
(6) Roll Steering. The bottom MFD outputs
roll steering to the flight director when the flight director
is valid and the course source is FMS.
e. HSI Graphic Format. The following graphics
are used on the EHSI during the HSI Mode. Refer to
(1) Course Readout/Label. When a valid
source is tuned, the course selected is displayed in
white. Next to the course readout is the label CRS or
DTK in white letters. The digital CRS or DTK readout
is always associated with the course source.
(a) Radial Source (VOR). The course
label is CRS and the digital course readout is
independently controlled by each MFD control panel.
(b) FMS -800 Operation. The label is
CRS when the primary source is not FMS. If the
primary source is tuned to FMS, the CRS will be
replaced with Desired Track (DTK) for all FMS modes
except TO / FROM mode (TACAN Emulation). When
FMS is the course source, the course is automatically
set by FMS.
(c) KLN 90B Operation. Refer to OBS /
LEG switch in Paragraph 3-7.al for a description of the
(2) FMS Message Alert. The message
(MSG) alert appears whenever the FMS sends an alert
to the MFD. The amber MSG alert indicates to the
crew that they should look at FMS on the selected side
of the cockpit [on-side/x (cross) side].
(3) FMS Heading Bug. The FMS heading
bug is only available for display when the FMS-800 is
the NAV source and the FMS is commanding the bug
to be displayed. The FMS heading bug is white and
travels about the aircraft symbol around the outer edge
of the compass. The center of the FMS heading bug
indicates the selected heading in 1 increments.
When the FMS selected heading is set, the FMS NAV
source label is replaced with FHDG 1 in white letters.
If the FMS selected heading is invalid, unavailable, or
the primary course source is not FMS 1, the heading
bug will not be displayed. The FMS-selected heading
bug is displayed in amber when a cross-side source is
(4) Course Deviation Scale. Four white
lateral deviation scale dots indicate deviation from
course. The course deviation scale rotates about the
aircraft symbol such that the scale is always
perpendicular to the selected primary course. The
maximum deviation is 2.5 dots. When the selected
course or source is invalid, the course deviation scale
is removed from the display.
The EHSI outputs lateral deviation and lateral
deviation validity to the flight director and/or autopilot.
The lateral deviation validity signal corresponds with
the selected course sources lateral deviation. The
lateral deviation output flag is displayed when the
lateral deviation for the selected primary navigation
source is invalid or an MFD failure results in bad or
failed lateral deviation output.
(5) Vertical Deviation Scale. The vertical
deviation scale, four small circles located on the right
side of the MFD, indicate the vertical deviation of the
(6) Vertical Deviation Pointer. The vertical
deviation pointer, represented by a white star, displays
the deviation with respect to the selected source.
(7) Lateral Deviation Bar. The center of the
course pointer moves laterally with respect to the
aircraft symbol and the four white deviation scale dots
to indicate lateral deviation. The course deviation
scale rotates about the aircraft symbol so that the
scale is always perpendicular to the selected primary
(8) Course Source Annunciations. The
navigation sensor is annunciated in white at the right
center of the display. The possible course source
annunciations are as follows.
1. FMS 1 or FHDG 1
2. FMS 2
3. VOR 1, TCN 1, LOC 1, or BC 1
4. VOR 2, LOC 2, or BC 2
The NAV source label is displayed in amber
when a cross-side source is selected. When both the
on-side and cross-side displays have the same NAV
source selected, the NAV source label is boxed in
If a NAV sensor failure is detected while selected
as the course source, the sensor annunciator
becomes red and boxed.
If FMS 1 is selected and a FMS NAV Warn
occurs, the FMS 1 course source annunciator turns