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The GNS 430 provides non-precision approach guidance using its built-in GPS
receiver. The GPS receiver can also be used as a supplemental aid for precision
approaches, but the localizer and glideslope receivers MUST be used for primary
approach course guidance.
Approaches designed specifically for GPS are often very simple and don’t
require overflying a VOR or NDB. Currently, many non-precision approaches have
“GPS overlays” to let you fly an existing procedure (VOR, VOR/DME, NDB,
RNAV, etc.) more accurately using GPS. To date, there are over 2,400 GPS-only
approaches and over 2,900 GPS overlay approaches.
Many overlay approaches are complex (in comparison to GPS-only approaches).
The GNS 430 displays and guides you through each leg of the approach—automati-
cally sequencing through each of these legs, up to the missed approach point
(MAP). Approaches may be flown “as published” with the full transition — using
any published feeder route or initial approach fix (IAF) — or may be flown with a
Approach operations on the GNS 430 will typically begin with the same basic
steps:1. Select the destination airport using the
key, or as the last waypoint in the active flight plan.
2. Choose the “Select Approach?” option from the procedures page (see page 66) or from the active
flight plan options (see page 61).
3. “Load” the approach (often while enroute) in anticipation of its future use. This places the
approach in the active flight plan, but retains course guidance in the enroute section until the
approach is “activated”.
4. “Activate” the full approach or vectors-to-final, as appropriate. In some scenarios, you may find it
more convenient to immediately activate the approach and skip the “Load” process outlined above
in step #3. The GNS 430 provides both options.
“Select” and “Load”
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hes with Pr
The procedure turn portion of an approach is stored as one of the legs of the
approach. For this reason, the GNS 430 requires no special operations from the
pilot — other than flying the procedure turn itself — beyond what is required for
any other type of approach.
This example uses the VOR
Runway 03 approach for Lynchburg
(Virginia) Regional Airport, KLYH,
and assumes a departure from
Frederick (Maryland) Municipal
Airport, KFDK. The steps required to
set up and fly the approach are
1. Prior to departing KFDK, the destination
(KLYH) is selected using the
key or by
creating a flight plan terminating at
2. While enroute to KLYH, some 40-50 nautical
miles away, you select the ATIS frequency to
monitor airport conditions and runway usage.
This is accomplished by selecting the NAV-
COM page (see page 39) and selecting the
ATIS frequency from the list. This places the
frequency on standby. Use the
make the ATIS frequency active.
From ATIS you learn that runway 03 is in use and plan your approach accordingly. Press the
key and select the “VOR 03” approach using the steps outlined on page 66. From the transitions
window, select LYH VOR (the IAF). Also, select “Load?” to load (but not activate) the approach.
4. Once you are cleared for the approach, press the
key, select “Activate Approach?” and
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Lynchburg (VA) Regional
VOR or GPS Rwy 03
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Flying the Pr
1. Within 30 nautical miles of the destina-
tion airport, the GNS 430 will switch from
“enroute” mode to “terminal” mode (as
indicated in the lower left corner of the
screen). The switch to terminal mode is
accompanied by a gradual Course
Deviation Indicator (CDI) scale transition
from 5.0 to 1.0 nautical miles, full scale
deflection. (See example, top left.)
2. Several miles prior to reaching the IAF
(LYH), you may wish to review the
approach sequence. Press the
key to display the active flight plan page.
Press the small right knob (
then rotate the large right knob (d
review each segment of the approach.
When finished, press
return to the previous page.
3. As you approach the IAF (LYH), a way-
point alert (“NEXT DTK 205°”) will
appear in the lower right corner of the
screen. As the distance (DIS) to the IAF
approaches zero, the alert is replaced by
a turn advisory (“TURN TO 205°”). Dial
the outbound course of 205° into the
CDI (or HSI) using the OBS knob and
standard rate turn to this course
4. Fly the outbound course, keeping the CDI needle centered.
5. Once you have flown approximately one minute past the FAF (LYH), the alert message “START
PROC TRN” will appear in the lower right corner of the screen. You may initiate the procedure turn
at any time after receiving this alert message.
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6. Turn left to a heading of 160° to initiate the procedure turn.
Course guidance is provided relative to the outbound leg from the
FAF. No guidance through the procedure turn itself is given. (The
procedure turn is displayed on the map page and indicated as the
active leg on the default NAV and active flight plan pages.) The
CDI needle will start moving to the right.7. After approximately one minute, make a 180° right turn to a
heading of 340° to intercept the inbound course. The GNS 430
will sequence to the inbound leg to the FAF, the CDI needle will
swing to the opposite side to provide proper sensing along the
final course segment and “NEXT DTK 025°” will appear in the
lower right corner of the screen.8. As the CDI needle starts to center, make a right turn to 025°—
the final approach course.
9. Within 2.0 nautical miles of the FAF (LYH), the GNS 430 will
switch from terminal mode to “approach” mode. CDI scaling will
be tightened from 1.0 to 0.3 nautical mile, full scale deflection.
10. As you approach the FAF, a waypoint alert in the lower right
corner ('NEXT DTK 026°') will appear. Make any course adjust-
ments necessary for the final course segment (FAF to MAP).
11. As you cross the FAF, the destination sequences to the MAP (“RW03”, the runway threshold). With the
needle centered, fly toward the MAP, observing the altitude minimums dictated by the approach plate.12.
As you approach the MAP, a waypoint alert (“APPRCHING WPT”) will appear in the lower right corner.
13. As you cross the MAP, “SUSP” will appear above the
key, indicating that automatic sequenc-
ing of approach waypoints will be suspended at the MAP. A “from” indication will be displayed on the
CDI and default NAV page, but course guidance along the final approach course will continue. If a
missed approach is required, use the
key to initiate the missed approach sequence, as
outlined on the following page.
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When viewing the map page, note that the final course segment is dis-
played in magenta (the active leg of the flight plan always appears in
magenta) and a dashed line extends the course beyond the MAP. The
dashed line is provided for situational awareness only and should NOT be
used for navigation. Follow the published missed approach procedures.
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Flying the Missed
After you pass the MAP, if the runway isn’t in sight you must execute a missed
approach. The GNS 430
continues to give guidance
along an extension of the
final course segment (FAF
to MAP) until you manually
initiate the missed
approach procedure (as
mentioned previously in
reference to the “SUSP”
used to initiate the missed
approach, as follows:
1. Press the
key. The missed approach holding point (MAHP; in this case “SWARM” intersec-
tion) is automatically offered as the destination waypoint.
2. Follow the missed approach procedures, as published on your approach plate, for proper climb
and heading instructions. The GNS 430 will guide you to the holding pattern, along the 053° radial
from LYH VOR.
In some cases, an additional hold waypoint is added to the missed
approach sequence. This additional waypoint is used as an aid in
establishing the holding pattern—especially where the MAP and
MAHP are the same waypoint.
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