Section 925
GARMIN GNC 420W
Page Date: 31. March 2009
925 - 3
Pilot´s Operating Handbook
EXTRA 300L
925.1
GENERAL
The Garmin GNC 420W GPS Navigator is a panel-mounted unit that contains a GPS receiver for
GPS navigation plus VHF Com radio in an integrated unit with a moving map and color display. The
GNC 420W features a graphical display which may also be used to depict terrain data.
This supplement is written for main software version 3.00 and GPS software version 3.0 and is not
suitable for earlier software versions. Some differences in operation may be observed when
comparing the information in this supplement to later software versions. Verify the information
herein with the 400W Series Pilot’s Guide & Reference (P/N 190-00356-00 applicable Revision) you
received with your unit. There you will also find further information.
925.1.1
GPS/WAAS TSO-C146A CLASS 3 OPERATION:
The Garmin GNC 420W uses GPS and WAAS (within the coverage of a Space-Based Augmentation
System complying with ICAO Annex 10) for enroute, terminal area, non-precision approach
operations (including „GPS“, „or GPS“, and „RNAV“ approaches), and approach procedures with
vertical guidance (including „LNAV/VNAV“ and „LPV“).
Navigation is accomplished using the WGS-84 (NAD-83) coordinate reference datum. GPS
navigation data is based upon use of only the Global Positioning System (GPS) operated by the
United States of America.
925.1.2
CLASS II OCEANIC, REMOTE, AND OTHER OPERATIONS:
The Garmin GNC 420W, as installed, has been found to comply with the requirements for GPS
primary means of Class II navigation in oceanic and remote airspace, when used in conjunction with
WAAS Garmin Prediction Program part number 006-A0154-03. Oceanic operations are supported
when the GNC 420W annunciates OCN. This provides an alarm limit of four NMI and a mask angle
Summary of Contents for 300L
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