The course/desired track readout and pointer on
the EHSI show the great circle desired track at current
aircraft position along the active leg. This may differ
from the CRS display on the CDU Flight Plan page
when the distance to the waypoint is large, especially
at high latitudes. The CRS display on the Flight Plan
page always references the inbound track measured
at the waypoint. Refer to Figure 3C-62.
When the inbound course to the active waypoint
is manually entered on the Flight Plan page, the
course display and course pointer on the HSI show the
desired course at the waypoint.
The scaling of the lateral deviation display on the
HSI is determined by the selected FMS flight guidance
mode selected on the Navigation Configuration page,
1. En route. 4.0 nm full scale (2 dots)
2. Oceanic. 4.0 nm full scale (2 dots)
3. Terminal. 1.0 nm full-scale linear
4. Approach. 0.3 nm full-scale linear
The scaling of the vertical deviation display on
the HSI is also determined by the current flight mode.
1000 feet full-scale deflection.
6. Approach. 300 feet full-scale
If no flight plan active waypoint is present and
the navigation solution is valid, the HSI display will be
blank removing current guidance information. If the
navigation solution is invalid, the navigation source
indicator will be red. If the navigation solution is valid
but performance is degraded, the navigation source
indicator will be yellow.
(3) Flight Director and Autopilot Lateral
(Bank) Steering. Using the Flight Director or autopilot,
the FMS can steer the aircraft directly through all of
the possible flight plan maneuvers including holding
patterns, MFPs, SIDs, STARs, and FMS approaches.
This interface also enables the FMS to limit the
commanded bank angle to the value specified on the
Navigation Configuration page.
The FMS provides a heading submode (FMS
heading) that allows the crew to temporarily fly to
selected headings while still using FMS waypoint
navigation. For those aircraft equipped with Electronic
Flight Instrument Systems (EFIS), select FMS heading
mode by pressing the HDG knob and adjusting the
knob to the desired heading. The FMS will provide
commanded bank to the selected heading indefinitely
or until the heading is adjusted in such a way as to re-
intercept the previous course.
Flight Instrument Systems. For those aircraft which
are equipped with an electronic flight display system
(EFIS or FDS), additional displays may be provided as
shown in Figure 3C-62.
1. Eight future flight plan waypoints
(including the active) to give advance
notice of impending leg changes and
relative distances to future waypoints
when the EHSI is in MAP mode,
2. Identification of the type of waypoint
(i.e., NAV aid, intercept, standard
waypoint, airport, etc.) and label
4. True Airspeed.
5. Wind direction and speed.
6. Time to go.
7. Bearing to Waypoint.
8. Elapsed Time.
(4) FMS Heading Mode Overview. The
vectoring to intercept a final approach course of a
published GPS approach, without the pilot needing to
deselect and reselect the flight control system NAV