GNC 420(A) Pilot’s Guide and ReferenceSECTION 3NAV PAGES3-15190-00140-20 Rev. K3.5 TERRAIN PAGENOTe: The TerraiN Page does not appear onGNC 420 units that are not properly equippedwith or configured for TerraiN. See Section 9for a full description of TerraiN functions.TERRAIN PageTo display the TERRAIN Page, select the NAV PageGroup and turn the small right knob until the TERRAINPage is displayed (Figure 3-26 and 3-27). The TERRAINPage displays:• GPS-derived MSL altitude shown in increments of20 feet or 10 meters, depending on unit configu-ration. The ‘G’ to right of the MSL altitude displayreminds the pilot that altitude is GPS-derived.• Aircraft ground track• Terrain Range - Indicates the terrain elevation incolors relative to the aircraft altitude• Range marking rings - (1 nm, 2 nm, 5 nm, 10 nm,25 nm, 50nm, and 100 nm)• Heading Indicator - The heading indication on theTERRAIN Page always displays ‘TRK’ for Track-up, unless there is no valid heading• Obstacles• Potential Impact PointsFigure 3-26 TERRAIN Page 120˚ ViewGPS-derivedMSL AltitudeRed Terrain (Warning - Terrain Above orWithin 100’ Below Aircraft Altitude)Number of Pages inCurrent Page GroupPosition ofCurrent Pagewithin CurrentPage GroupCurrent Page GroupHeadingIndicatorFigure 3-27 TERRAIN Page 360˚ ViewYellow Terrain (Caution- Terrain Between 100’and 1000’ Below AircraftAltitude)Black Terrain (No Danger- Terrain More than1000’ Below AircraftAltitude)RangeMarkingRingSelectable Display SettingsThe TERRAIN Page has two selectable view settings:• 360˚ View - View from above aircraft depictingsurrounding terrain on all sides• 120˚ View - View of terrain ahead of and 60˚ toeither side of the aircraft flight path (Figure 3-27)NOTe: The TerraiN Page gives a ‘Track Up’display orientation, as indicated by the ‘TrK’label shown on the display. This is the onlyorientation available on this page.