If the KLN 90B is in the OBS mode, the
selected course (OBS) is displayed instead
of the Desired Track (DTK).
FLY L 2.7NM
Figure 3-11. NAV 3 Page
(b) Actual Track (TK). The aircraft's
present track over the ground.
(c) Cross Track Error Correction. This is
a text means of indicating how far and which direction
to get back on course. It is consistent with the vertical
deviation bar displayed on the NAV 1 page.
(d) Minimum Safe Altitude (MSA). The
MSA displayed is the altitude defined by Jeppesen as
Grid Minimum Off-Route Altitude (Grid MORA). This
altitude is derived by Jeppesen for sectors that are 1°
of latitude by 1° of longitude in size. One degree of
latitude is 60 nm. One degree of longitude is 60 nm at
the equator and progressively less than 60 nm as one
travels away from the equator. One degree of
longitude is approximately 50 nm at the southern most
parts of the U.S. and is approximately 40 nm at the
northern most parts of the U.S. The MSA altitude
information is contained in the database and is
updated when the database cartridge is updated.
The MSA provides reference point clearance
within these 1° latitude by 1° longitude sectors. A
reference point is defined as a natural (peak, knoll, hill,
etc.) or man-made (tower, stack, tank, building, etc.)
object. Grid MORA values clear all reference points
by 1000 feet in areas where the highest reference
points are 5000 feet MSL or lower. MORA values
clear all reference points by 2000 feet in areas where
the highest reference points are above 5000 feet MSL.
The KLN 90B displays dashes for areas outside the
database coverage area or for areas where the Grid
MORA is not defined.
The MSA and ESA altitudes are advisory in
nature only. They should not be relied
upon as the sole source of obstacle and
minimum clearance altitudes.
(e) Minimum En Route Safe Altitude
(ESA). When the KLN 90B is in the leg mode, the
ESA is the highest MSA from the present position to
the active waypoint, then to the destination waypoint
via the active flight plan. Refer to Figure 3-12. When
the KLN 90B is in the OBS mode, the ESA is the
highest MSA from the present position to the active
Figure 3-12. Minimum En route Safe Altitude
(4) NAV 4 Page. The NAV 4 page is used
for altitude alerting and for advisory vertical navigation.
Refer to Figure 3-13.
E N R - L E G
Figure 3-13. Altitude Page and NAV 4 Page
(a) Altitude alerting allows the selection
of a target altitude and then provides a visual alarm
1000 feet prior to reaching the selected altitude,
another upon reaching the altitude and another for
deviation from the selected altitude.