Garmin GNC 420AW GPS Receiver User Manual


 
5 - PROCEDURES
85
190-00356-00 Rev E
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overying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 Localizer Performance with Vertical guid-
ance (LPV) approach. Fly to LPV minimums.
A yellow background indicates that the ap-
proach is safe to continue but a downgrade
to LNAV may occur.
LP
Localizer Performance with no vertical guid-
ance. Fly to LP minimums. SW V 3.30, or later.
L/VNAV Lateral Navigation and Vertical Navigation
(LNAV/VNAV) approach. Fly to LNAV/VNAV
minimums.
LNAV+V Non-precision GPS approach with advisory
vertical guidance. Note that some LNAV/
VNAV approaches are not yet marked in
the database as such and will show up as
LNAV+V. If the chart shows the approach as
LNAV/VNAV, it can be flown to LNAV/VNAV
minimums.
LNAV Lateral Navigation approach. Fly to LNAV
minimums.
MAPR Missed Approach indicates the system is
providing missed approach integrity and CDI
full-scale deflection ±0.3 NM.
ENR En route, CDI full-scale deflection is 2.0 NM
or current CDI scale selection, whichever is
smaller.
TERM Terminal, CDI full-scale deflection is 1.0 NM
or current CDI scale selection, whichever is
smaller.
DPRT Departure, indicates the system is using
non-precision approach integrity. HAL = 0.3
and CDI full-scale deflection is 0.3 NM.
OCN Oceanic, CDI full-scale deflection is 2.0 NM.
LOW ALT
(lower window)
For LNAV+V, LNAV/VNAV, or LPV ap-
proaches, the LOW ALT annunciation
indicates the aircraft’s estimated height is
lower than the Final Approach Waypoint
height by more than the current VPL plus 50
meters. This annunciation will not be active
when Terrain is operational.