TM 1-1510-218-10
3-54
4. If the ENT button was pressed, the
KLN 90B will calculate an arc intercept
point based on the present track of the
aircraft over the ground.
NOTE
If the present track does not intercept the
arc, the KLN 90B will display NO INTRCPT
in the scratchpad area of the screen.
(8) When the aircraft approaches the arc, the
KLN 90B will provide waypoint alerting and turn
anticipation to join the arc.
(9) Once established on the arc, the KLN
90B provides left/right guidance relative to the curved
arc. Distance to the active waypoint is the distance
from the present position to the active waypoint, not
the distance along the arc.
(10) During the arc, the desired track will be
constantly changing. To help keep the orientation
correct, the Super NAV 5 page will automatically
display DTK on the sixth line. It is not possible to
change this while on the arc. The value displayed for
the desired track will flash when the difference
between the CDI or HSI and the current desired track
is greater than 10°.
(11) Some DME arcs have defined radials that
serve as step down fixes. These points are not stored
in the database. To help determine the position
relative to these step down points along the arc, the
KLN 90B will display a new value on the bottom line of
the display on the Super NAV 5 page. This
designation is the letters ARC followed by three
numbers. The three numbers represent the current
radial the aircraft is on relative to the reference
VOR/DME. It is not possible to select any other
information to display on this line. The arc radial is
forced into this position when the aircraft is 30 nm from
the arc.
NOTE
Autopilot
performance
may
not
be
satisfactory if coupled in the NAV mode
while flying the arc. Many autopilot
systems were never designed to fly curved
paths.
If
autopilot
performance
is
unsatisfactory
while
flying
DME
arcs,
select
the
heading
mode
and
keep
changing the heading bug to keep the
deviation bar centered.
(12) As the aircraft approaches the end of the
arc, the KLN 90B will provide waypoint alerting and
turn anticipation to the next leg.
(13) When the aircraft is 2 nm from the FAF,
the KLN 90B will attempt to transition to the approach
active mode. Since the DME arc procedure is flown
entirely in the LEG mode, the only possible problem
would be if the integrity monitoring were not available.
(14) If a missed approach is needed, perform
the following.
1. If the missed approach calls for a
climb and then a turn, the KLN 90B
will provide correct guidance for the
climb.
2. Once the correct altitude has been
reached, press the D button. The
first point in the published missed
approach will be the default DIRECT
TO waypoint. Press the ENT button
to confirm the DIRECT TO waypoint.
NOTE
If
ATC
instructions
for
the
missed
approach are different from the published
missed approach procedure, it is always
possible to select a different DIRECT TO
waypoint.
If another attempt at the approach is
desired after holding, it is necessary to
manually change the active waypoint.
When the FAF and the missed approach
holding point are the same, the KLN 90B
will
automatically
change
the
active
waypoint to the FAF when the change from
OBS to LEG is made. This change needs
to be made as soon as possible to ensure
the approach active mode becomes the
active mode.
3. The OBS mode will need to be
selected to either fly a specific course
or radial to the waypoint or to hold at
the missed approach holding point. If
this is not done before the aircraft gets
to 4 nm from the missed approach
holding point, the KLN 90B will
provide a reminder message to select
OBS.
aw. Approach Problems. Very rarely, there will
be a problem with the integrity of the GPS system
while conducting non-precision approaches. In some
cases, the KLN 90B will determine that there will not
be sufficient integrity monitoring for the leg between
the FAF and the MAP, or RAIM is not currently
available. In these cases, the KLN 90B will not go into
the approach active mode and will present the
