Example Approach: Dme Arc - Honeywell KLN 900s Pilot's Manual

6.1.8 Example Approach: DME Arc

DME arc procedures with the KLN 900 are completely dif-
ferent from using traditional VOR and DME equipment.
Don't worry though because DME arc procedures using
the KLN 900 are also easier than using traditional equip-
ment. This is because the KLN 900 provides left/right
guidance around the arc. No more having to watch dis-
tance in one place and radial in another!
Very rarely do you actually fly to the beginning of an arc,
especially in a radar environment. Instead, the flight path
of the aircraft generally intersects the arc at some point.
Once the aircraft is near the arc, it is then possible to turn
so that the arc distance is maintained until time to turn to
the inbound fix.
The following example will show how DME arc proce-
dures are flown using the KLN 900. This example
approach will be to use the VOR RWY 12 approach to
Owatonna, Minnesota, KOWA. The approach plate for
this approach is in figure 6-22. Assume that the aircraft is
approaching from the North and is in a radar environ-
ment.
1. ATC assigns the VOR RWY 12 approach. Turn to
the APT 8 page for KOWA to select the approach. You
select the VOR 12 approach and the KLN 900 presents
the IAF selection page (figure 6-23).
2. There are five choices for the IAF. Three of these
choices you can recognize but the other two, D040L and
D220L, are unfamiliar and not shown on this chart.
These two waypoints are the database identifiers for the
ends of the arc. D040L means DME arc point, 040 is the
radial which the waypoint lies, and L indicates the dis-
tance of the arc. L is the twelfth letter of the alphabet so
the L indicates that this is an arc with a radius of 12 NM.
In a similar manner D220L can also be decoded. In this
example the aircraft is approaching from the north so the
D040L IAF will be selected.
3. The KLN 900 knows that this point is associated with
a DME arc. Once an arc waypoint is chosen, the KLN 900
determines what radial of the reference VOR the aircraft
is presently located on. A waypoint is created that is
located at the intersection of the present radial and the
DME arc. This waypoint is the first waypoint in the list of
waypoints presented on the APT 8 page before loading
the approach into the flight plan (figure 6-24). This way-
point is named using the same convention discussed
earlier.
NOTE: If the present radial from the reference VOR is
outside of the defined arc, then the KLN 900 will default to
the beginning of the arc.
CAUTION: The KLN 900 does not take into account
the geometry of the active flight plan when determin-
ing the arc intercept point. This point is defined
6-16
Figure 6-22
|V12-KOWA
|IAF 1 ALMAY
| 2 D040L
| 3 D220L
| 4 FOW
| 5 MKT
ent CRSR
Figure 6-23
|V12-KOWA
| 1 D011Lì
| 2 D310L
| 3 FOWî
| 7 FOWï
|LOAD IN FPL
ent CRSR
Figure 6-24
Rev 2