The course to fly while in this mode is referred to as
the DTK. The desired track is displayed on the NAV 3
and D/T 3 pages. The Super NAV 5 page can also be
configured to display the desired track. To fly a great
circle course between two points, the desired course
may be constantly changing.
(c) Automatic waypoint sequencing is
provided during flight plan operation. As a waypoint is
reached, the next leg of the flight plan automatically
(d) Turn anticipation may be utilized in
flight plan operation.
(e) The minimum En route Safe Altitude
(ESA) displayed on the NAV 3 page is the highest
MSA sector altitude from the present position to the
destination waypoint along the active flight plan or
direct to route, whichever is in use.
(3) OBS Mode.
(a) The default CDI sensitivity is ± 5 nm,
full scale. This applies to the CDI on the NAV 1 page
as well as the external HSI. If the HSI has five dots
left and right of the center position, each dot
represents one nautical mile of deviation.
In some installations where the KLN 90B is
interfaced to certain models of EFIS
equipment, the scale factor will be ±
7.5 nm, full scale.
(b) The course is defined by the active
waypoint and the selected magnetic course. A course
to or from the waypoint may be selected.
(c) The course selection is normally
made by changing the selected course displayed on
an external indicator such as an HSI or EFIS. When
this is done, the pilot must verify that the proper course
has been selected by confirming the digital selected
course readout displayed on the KLN 90B. In the OBS
mode, the selected course is always displayed as part
of the mode annunciation at the bottom center of the
screen on all pages except the Super NAV 5 page.
Refer to Figure 3-53. On the Super NAV 5 page, the
mode/annunciation is displayed on the left side of the
screen. Two or more navigation sources can be
selected as the primary navigation source displayed
on the HSI or EFIS. The primary navaid selector
switch on the pilot's side of the instrument panel is
used to determine the navigation source displayed.
For the KLN 90B to properly read the external
indicator, the KLN 90B must be the displayed
navigation source on the external indicator.
Figure 3-53. OBS Mode Indications
When the KLN 90B is not the displayed
navigation source on the external indicator or if the
KLN 90B is interfaced with an EFIS system, it is
possible to change the selected course from several
pages on the KLN 90B. This can be done from the
NAV 3 page, the MOD 2 page, and the Super NAV 5
page if it is configured to display the track on the left-
To tell if it is possible to enter the OBS
value, note the OBS field. If a colon
follows the letters OBS, it is possible to
enter a value. If the colon is missing, the
course must be changed from the external
If the KLN 90B is interfaced to EFIS or an
electrically driven mechanical indicator,
the external indicator will be slewed to
agree with what was entered on the KLN
1. Select the NAV 3, MOD 2, or
Super NAV 5 page.
button to turn on the cursor
function. If the course is being
changed from the Super NAV 5
page, use the left outer knob to
rotate the cursor over the OBS
3. Turn the appropriate inner knob to
select the course.
4. Press the CRSR button to turn off
the cursor function.
(d) There is no automatic leg sequencing
or turn anticipation.
(e) The minimum ESA displayed on the
NAV 3 page is the highest MSA sector altitude from
the present position to the active waypoint. Other