Garmin GNC 420AW Pilot's Manual

Also see for GDL 69: Pilot's guide addendum Pilot's guide addendum Activation Instructions Activation Instructions Pilot's guide addendum

Contents

Garmin GNC 420AW Pilot's Manual Manual pdf 44 page image

38Part Three: Section 2TAWS AlertsSection 3: TAWS AlertsAlerts are issued when flight conditions meetparameters that are set within TAWS softwarealgorithms. TAWS alerts typically employ either aCAUTION or a WARNING alert severity level, orboth. When an alert is issued, visual annunciationsare displayed. Aural alerts are simultaneously issued.Annunciations appear in a dedicated field in the lowerleft corner of the display.TAWS Annunciation FieldTAWS Annunciation FieldAnnunciations are color-coded according to theTAWS Alert Summary table. Pop-up terrain alerts canalso appear during an alert, but only when the TAWSPage is not displayed. There are two options whenan alert is displayed:To acknowledge the pop-up alert and return tothe currently viewed page:Press the CLR button.To acknowledge the pop-up alert and quicklyaccess the TAWS Page:Press the ENT button.NOTE: To further capture the attention of the pilot,TAWS issues aural (voice) messages that accompanyvisual annunciations and pop-up alerts. Some auralmessages are configurable during installation of thesystem. For a summary of aural messages, see theTAWS Alert Summary table.NOTE: TAWS Caution Alerts are displayed as constantblack text on a yellow background; TAWS WarningAlerts are displayed as constant white text on a redbackground.Forward Looking Terrain AvoidanceThe unit will issue terrain alerts not only when theaircraft altitude is below the terrain elevation butalso when the aircraft is projected to come withinminimum clearance values of the terrain. Thisalerting, called Forward Looking Terrain Avoidance(FLTA), is also provided for obstacles. Any potentialimpact points are depicted on the display. Thereare 2 levels of severity for FLTA alerts. They arecautionary (amber) and warning (red) in nature andare described in further detail below.CAUTION—Estimated potential impact in approximately 30 sec-onds after a FLTA Caution pop-up alert and annunciation. FLTAcaution alerts are accompanied by the aural message “CautionTerrain; Caution Terrain” OR “Terrain Ahead; Terrain Ahead”.Similarly, a “Caution Obstacle; Caution Obstacle” or “ObstacleAhead; Obstacle Ahead” alert is also provided. The time to analert can vary with conditions, therefore there is no guaranteeof a 30 second caution alert being issued.190-00356-30 Rev H