TM 1-1510-225-10
3D-52
the display on the Super NAV 5 page. This value is
denoted by 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.
(13)As the aircraft approaches the end of the
arc, the KLN 90B will provide waypoint alerting and
turn anticipation to the next leg.
(14)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 was not available.
(15)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.
NOTE
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.
k. 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
message, RAIM NOT AVAILABLE, APR MODE
INHIBITED, PREDICT RAIM ON STA 5.
(1) The approach must be discontinued. The
STA 5 page provides a means to predict when RAIM
will be available.
(2) To perform a RAIM prediction on the
STA 5 page, two pieces of information are needed:
the location that the prediction will be for and the time
for the prediction.
(3) The destination waypoint will, by default,
be the missed approach point of an approach loaded
in the flight plan. If there is no approach in the flight
plan, the default waypoint is the last waypoint in the
active flight plan. It is possible for the pilot to enter any
desired waypoint in this field.
(4) The time used for the RAIM prediction will
be the current ETA to the destination airport or the
MAP. This time is automatically updated by the KLN
90B so there is no need to enter a value. If a RAIM
prediction is desired for planning purposes, it is
possible to enter a time in this field. The time used for
the RAIM prediction is always in the future and is
limited to 24 hours from the present time.
