Garmin GNC 420AW, Pilot'S Manual & Reference

Page: 93 / 214

5 - PROCEDURES
83 190-00356-00 Rev B
Basic Approach Operations
Basic Approach Operations
The 400W series provides precision vertical guid-
ance and non-precision advisory guidance using its
built in GPS receiver. The moving map pages can also
be used as a supplemental aid to situational awareness
for ILS, VOR, and NDB approaches (and non-preci-
sion localizer-based approaches), but the appropriate
navigational aid 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
worldwide.
Many overlay approaches are more complex (in
comparison to GPS-only approaches). The 400W-
series unit displays and guides you through each leg
of the approach — automatically 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
vectors-to-final transition.
Flight mode annunciations are provided in the
lower left corner of the display indicating the current
mode of flight.
Annunciation Description
LPV Lateral Precson wth Vertcal gudance
(LPV) approach. Fly to LPV mnmums. A
yellow background ndcates that the ap-
proach s safe to contnue but a downgrade
to LNAV may occur.
L/VNAV Lateral Navgaton and Vertcal Navgaton
(LNAV/VNAV) approach. Fly to LNAV/VNAV
mnmums.
LNAV+V Lateral Navgaton (LNAV) approach wth
Advsory Vertcal gudance. Fly to LNAV
mnmums.
LNAV Lateral Navgaton approach. Fly to LNAV
mnmums.
MAPR Mssed Approach, ndcates the system s
provdng mssed approach ntegrty and
CDI full-scale deflecton ±0.3 NM. Ths also
shows that the plot has ntated a Mssed
Approach by pressng the
OBS key after
crossng the MAP.
ENR En route, CDI full-scale deflecton s 2.0 NM
or current CDI scale selecton, whchever s
smaller.
TERM Termnal, CDI full-scale deflecton s 1.0 NM
or current CDI scale selecton, whchever s
smaller.
DPRT Departure, ndcates the system s usng
non-precson approach ntegrty. HAL = 0.3
and CDI full-scale deflecton s 0.3 NM.
OCN Oceanc, CDI full-scale deflecton s 2.0 NM.
LOW ALT
(lower wndow)
For LNAV+V, LNAV/VNAV, or LPV approach-
es, the LOW ALT annuncaton ndcates the
arcraft’s estmated heght s lower than the
Fnal Approach Waypont heght by more
than the current VPL plus 50 meters. Ths
annuncaton wll not be actve when TAWS
s operatng on unts equpped wth TAWS.