waypoints in the active flight plan do not affect the
(f) When the active waypoint is a VOR
or approach waypoint, the published magnetic
variation for the VOR or approach waypoint is utilized
rather than the calculated magnetic variation.
(4) Switching From The LEG Mode To The
OBS Mode. The following mode transition occurs if
the KLN 90B is in the LEG mode and the mode is
changed to OBS.
(a) The waypoint that was active in LEG
mode prior to the mode change remains the active
waypoint in OBS mode.
(b) The selected course is defined by two
different methods depending on the installation and
status of the unit.
1 If the KLN 90B is the displayed
navigation source when the change is made to the
OBS mode, the selected course becomes whatever
was set on the external indicator prior to changing to
the OBS mode. This value should normally be the
desired track to the active waypoint that was already
set on the external indicator if it was set pictorially
2 If the KLN 90B is interfaced with a
compatible EFIS, electrically driven mechanical HSI, or
is not displayed on the external indicator, the selected
course is chosen by the KLN 90B such that the
deviation from the selected course remains the same.
(c) If the OBS value chosen by default is
unacceptable, the pilot may choose the OBS value as
described in Paragraph 3-7al(3).
(5) Switching From The OBS Mode To The
LEG Mode. The following mode transition occurs if the
KLN 90B is in the OBS mode and is switched to the
(a) The active waypoint, while in the OBS
mode, remains the active waypoint when the LEG
mode is activated. The system does not attempt to
orient itself on a leg of the active flight plan unless the
TO / FROM indicator is indicating FROM. In this case,
the KLN 90B will reorient on the active flight plan.
(b) The active selected course in the
OBS mode prior to switching to a LEG mode becomes
the desired track in the LEG mode, unless the switch
was made on the FROM side, in which case the KLN
90B will calculate the correct desired track for the new
(c) With the exception of (b) above, the
characteristics of normal DIRECT TO operation apply.
(6) Going Direct To A Waypoint While In The
OBS Mode. The DIRECT TO function will select the
OBS value that will take the aircraft from the present
position direct to the active waypoint when the KLN
90B is interfaced to a compatible EFIS, an electrically
driven mechanical HSI, or when the KLN 90B is not
the displayed navigation source on the external
If the KLN 90B is the displayed navigation
source on a non-driven HSI, it is not possible for the
KLN 90B to change the OBS value. In these
situations, the KLN 90B will provide a scratchpad
message that will announce the OBS value that should
be selected to go direct to the active waypoint. Refer
to Figure 3-54.
D CRS 234
+ + + + + + + + + +
Figure 3-54. OBS DIRECT TO Course
(7) Activating A Waypoint While In The OBS
Mode. While in the OBS mode, a waypoint may be
activated by using the normal DIRECT TO method or
by a second method. This second method activates
another waypoint without changing the selected
course. When the new waypoint is activated, the
deviation bar is not centered.
1. Press the D button. The rules for
the priority of waypoint selected for
direct to operation apply.
2. Press the D button a second time.
changes to ACTIVATE. The right side
still displays the appropriate waypoint
page. Repeated presses of the
DIRECT TO and ACTIVATE. Ensure
ACTIVATE is displayed. Refer to