Garmin aera 660 Pilot’s Guide 190-02017-20 Rev. A94Hazard AvoidanceOverviewNavigationFlight PlanningHazard AvoidanceAdditional FeaturesAppendicesIndexTerrain and obstacle databases are referenced to MSL. Using the GPS positionand altitude, the Terrain feature portrays a 2-D picture of the surrounding terrain andobstacles relative to the position and altitude of the aircraft. GPS position and GPS-MSL altitude are used to calculate and predict the aircraft’s flight path in relation to thesurrounding terrain and obstacles. In this way, the pilot can view predicted dangerousterrain and obstacle conditions.Alert windows appear to inform the pilot of proximity to the terrain and obstacles,as well as an unsafe descent rate. These alerts depend on user-defined parameters inthe Terrain Setup.TERRAIN INFORMATIONTwo views are displayed by the Terrain function: the Map View, and the Profile View.The areas of the terrain shaded red are predicted to be within 100 feet below orabove the aircraft. The yellow terrain areas are between the user-defined CautionElevation and 100 feet below the aircraft. By default, the Caution Elevation is 1,000feet; therefore, the areas in yellow are between 1,000 feet and 100 feet below theaircraft. The black areas are further than the Caution Elevation. A projected point ofimpact is marked with an “X” symbol.OBSTACLE INFORMATIONObstacles are shown on the Terrain Map View, at or below the map range of 12 nm.Obstacles are also shown on the Navigation Map when the map range is set to 5 nmor below.Standard aeronautical chart symbols are used for lighted or unlighted obstaclestaller than 200 feet Above Ground Level (AGL). Refer to the Obstacle Icons legendbelow.When selecting an obstacle with the Map Pointer, each obstacle displays the altitudeat the top of the obstacle, or Mean Sea Level (MSL). Each obstacle also lists the actualheight of the obstacle, or Above Ground Level (AGL).
