Garmin GNC 420 Pilot's Manual & Reference

Also see for GNC 420: Instructions Pilot's guide addendum Pilot's guide addendum Pilot's guide addendum Quick reference

Contents

Garmin GNC 420 Pilot's Manual & Reference Manual pdf 76 page image

68Basic Approach OperationsThe GNC 420 provides non-precision approach guidance using its built-in GPSreceiver. The GPS receiver can also be used as a supplemental aid for precisionapproaches, but external localizer and glideslope receivers MUST be used for primaryapproach course guidance.Approaches designed specifically for GPS are often very simple and don’trequire 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 over2,900 GPS overlay approaches.Many overlay approaches are complex (in comparison to GPS-only approaches).The GNC 420 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 publishedfeeder route or initial approach fix (IAF)—or may be flown with avectors-to-final transition.Approach operations on the GNC 420 will typically begin with the same basic steps:1. Select the destination airport using the D 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 flightplan options (see page 59).3. “Load” the approach (often while enroute) in anticipation of its future use. This places the approach in theactive 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 moreconvenient to immediately activate the approach and skip the “Load” process outlined above in step #3.The GNC 420 provides both options.Select Destination“Select” and “Load”the approach“Activate” theapproachPROCEDURESBasic ApproachOperations5