Example Approach: On-Airport Navaid - Honeywell KLN 900s Pilot's Manual

6.1.7 Example Approach: On-Airport Navaid

Another common type of approach is an approach that is
based on an on-airport navaid. These could be either
VOR or NDB approaches. An example of this type of
approach is the VOR RWY 24 approach to Bowman
airport in Louisville, Kentucky (Figure 6-21). The airport
identifier for this airport is KLOU.
For this example assume that the aircraft is approaching
KLOU from the Nabb VOR.
1. After passing the Nabb VOR, you are told to expect
the VOR 24 approach at KLOU. You load the approach
using the procedure described in section 6.1.1 and select
the BQM IAF.
2. When the distance from the present position to the
destination airport reaches 30 NM, the KLN 900 will auto-
matically arm the approach mode. The CDI scale factor
will transition from ±5.0 NM to ±1.0 NM and the KLN 900
will provide more sensitive integrity monitoring. You also
press A to update the barometric information.
3. When the aircraft is 4 NM from the BQM VOR, the
KLN 900 will give a message reminding you to select the
OBS mode. The OBS mode is required for the procedure
turn. In this case, don't select the OBS mode until after
the KLN 900 has sequenced past BQM-i and made the
FAF, FF24-f, the active waypoint. (This will keep you from
having to manually activate FF24-f while in the OBS
mode.) After passing BQM, select OBS mode and then, if
required, select the outbound course of 068° on the exter-
nal CDI or HSI. The TO-FROM flag will change from TO
to FROM passing over FF24.
4. With the OBS mode selected and FF24 as the active
waypoint, it is possible to fly the procedure turn. Allow
enough distance past FF24 to complete the procedure
turn and still be 2 NM away before reaching the FAF.
Remember that the procedure requires you to remain
within 10 NM of BQM during the procedure turn. After
Figure 6-21
completing the heading portion of the procedure turn,
change the selected course to the inbound course of 248°
on the external CDI or HSI.
5. Once established on the inbound course the Leg
mode will again need to be selected so that proper
approach operation and waypoint sequencing will occur.
NOTE: It is mandatory that the unit be in LEG mode with
the FAF as the active waypoint before crossing the FAF
to activate the approach active mode and change to a
±0.3 NM scale factor. The CDI scale factor changes from
±1.0 NM to ±0.3 NM over the two miles to the FAF.
Delaying the switch from OBS to Leg mode compresses
the scale factor change. This makes the transition more
abrupt. If the switch from OBS to Leg is delayed too long
it will not be possible for the KLN 900 to change to the
approach active mode.
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