Garmin GNS 420AW, Quick Reference Manual

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18
190-00356-01 Rev F
APPROACHES
maintained. If this occurs, the GPS receiver should not
be used for primary navigation guidance. Revert to an
alternate navigation source, or select an alternate desti-
nation airport. LPV, LNAV+V, and L/VNAV approaches
will downgrade to LNAV if GPS integrity cannot be
met. There is no need to switch to guidance by other
navigation equipment unless GPS LNAV is insufficient
or integrity degrades further.
• Within 31 nautical miles of the destination airport, CDI
scaling will transition from 2.0 NM (en route mode, or
“ENR”) to 1.0 nautical mile (terminal mode, or “TERM”).
Conversely, when leaving the departure airport, CDI scal-
ing will transition from 1.0 NM to 2.0 NM when 30 miles
out. GPS-based approaches will see a second transition
when within 2.0 NM of the final approach fix, scaling
from 1.0 NM to angular full-scale deflection (approach
mode, or “LNAV, LNAV+V, L/LNAV, or LPV”).
• A "RT TO xxx° x S" or "LT TO xxx° x S" prompt will
appear in the lower right corner of the display to advise
you when you are at a safe distance to initiate a procedure
turn. The procedure turn is displayed on the map page,
but guidance through the turn itself is not provided
except via roll steering-equipped autopilots .
• Alerts for proper holding pattern entry (e.g. “HOLD
DIRECT”) are displayed in the lower right corner of the
display. Waypoint sequencing is automatically suspended
(indicated by “SUSP” directly above the
OBS key) at the
holding waypoint. Press the OBS key again to return to
automatic waypoint sequencing. For course reversals,
waypoint sequencing is suspended for one trip around
the holding pattern only, after which it will return to
automatic waypoint sequencing.
• The CDI will guide you through a DME arc. Just keep
the needle centered as you fly along the arc.
• As you cross the missed
approach point, “SUSP” will
appear above the
OBS key,
indicating that automatic
sequencing of waypoints
is suspended at the missed
approach point, and a “from” indication will appear on
the CDI (or HSI).
Flying the Missed Approach
1. After crossing the Missed Approach Point, press
the
OBS
key. The next waypoint in the approach
is automatically offered as the destination
waypoint.
2. Follow the missed approach procedures, as pub-
lished on your approach plate, for proper climb and
heading instructions.
3. An alert message in the lower right hand corner
of the screen will recom-
mend entry procedures for
the holding pattern (e.g.,
“HOLD TEARDROP”). As
you fly the holding pat-
tern, a timer appears on
the default NAV page. The timer automatically
resets on the outbound side of the hold when you
are abeam the hold waypoint. The timer again
resets as you turn inbound (within approximately
30° of the inbound course).
4. The unit will provide course guidance only on the
inbound side of the holding pattern, however guid-
ance is provided along the entire holding pattern
via roll steering-equipped autopilots. When leav-
ing the holding pattern to re-fly the approach (or
another approach) press the
PROC key to “Select
Approach?” or “Activate Approach?” as previously
described. (Or, use the
direct-to key to select
another destination).