TM 1-1510-225-10
3D-38
(4) The present time.
(5) The estimated time of arrival at the
destination waypoint.
(6) The Flight Time. If RUN WHEN GS > 30
knots is selected on the SET 4 page, flight time is the
amount of time that the aircraft’s groundspeed has
been above 30 knots. Normally, this will be the time
since takeoff. However, time spent at groundspeeds
less than 30 knots, such as intermediate stops without
shutting down power, is not counted as flight time. If
RUN WHEN POWER IS ON is selected on the SET 4
page, flight time is the time since power on.
(7) Estimated
time
en
route
to
the
destination.
3D-20. MODES OF OPERATION.
The course to the active waypoint is defined by
selecting between two course modes, LEG and OBS.
The LEG mode means the course to the active
waypoint is selected by the KLN 90B. It is the default
mode when power is applied to the KLN 90B. The
OBS course mode is the mode that allows the pilot to
define the course to the active waypoint.
The KLN 90B also has three modes that are
associated with approach operation: En Route,
Approach Arm, and Approach Active.
The status of the course modes and the
approach modes are annunciated in the lower center
segment of the screen. The exceptions to this are on
the turn on page where the mode is not annunciated
and on the Super NAV 5 page where the mode is
annunciated on the left side of the screen. The
abbreviations used for mode annunciation are detailed
in Table 3D-14.
Table 3D-14. Course Modes
DISPLAY
EXPLANATION
APR – LEG
Approach Active – Leg
ARM – LEG
Approach Arm – LEG
ARM : 259
Approach Arm – OBS
ENR – LEG
En route – Leg
ENR: 274
En route – OBS
The approach active – OBS mode is not a valid
mode and cannot be selected. For the OBS modes,
the number included in the annunciation is the
magnetic course selected by the pilot.
a. Selecting the Mode. The mode cannot be
selected with the MOD pages because the external
course mode selector/annunciator is used.
1. Locate
the
external
course
mode
selector/annunciator.
2. Press the switch and it will change the
modes and annunciate the mode selected.
b. Leg Mode. The characteristics of the leg
mode are as follows.
(1) The default Course Deviation Indicator
(CDI) sensitivity is ± 5 nautical miles, full scale. This
applies to the CDI on the NAV 1 page as well as the
external EHSI. If the EHSI has five dots left and right
of the center position, each dot represents one
nautical mile of deviation.
NOTE
In some installations where the KLN 90B is
interfaced
to
certain
models
of
EFIS
equipment, the scale factor will be plus or
minus 7.5 nm, full scale.
(2) Navigation is provided along the great
circle path between two waypoints. Great circle
navigation is the shortest distance between two points
located on the earth's surface. In case of Direct To
operation, the From waypoint is not displayed but it is
the point where direct to operation was initiated. 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.
(3) Automatic
waypoint
sequencing
is
provided during flight plan operation. As a waypoint is
reached, the next leg of the flight plan automatically
becomes active.
(4) Turn anticipation may be utilized in flight
plan operation.
(5) 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.
c. OBS Mode.
(1) The default CDI sensitivity is ± 5 nautical
miles, full scale. This applies to the CDI on the NAV 1
page as well as the external EHSI. If the EHSI has
