Garmin GNC 420AW Quick Reference Manual - Page 20

Browse online or download pdf Quick Reference Manual for Marine GPS System Garmin GNC 420AW. Garmin GNC 420AW 25 pages. Garmin gps receiver quick reference guide
Also for Garmin GNC 420AW: Pilot's Manual Addendum (24 pages), Pilot's Manual Addendum (24 pages), Supplementary Manual (12 pages)

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1. Model Descriptions

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.

APPROACHES

• 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

After crossing the Missed Approach Point, press

the OBS key. The next waypoint in the approach

is automatically offered as the destination

waypoint.

Follow the missed approach procedures, as pub-

lished on your approach plate, for proper climb and

heading instructions.

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).

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).

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