11-15190-01007-03 Rev. B Garmin GTN 725/750 Pilot’s GuideForewordGettingStartedAudio &Xpdr CtrlCom/NavFPLDirect-ToProcChartsWpt InfoMapTrafficTerrainWeatherNearestMusicUtilitiesSystemMessagesSymbolsAppendixIndex11.3.8.2 Excessive Descent Rate AlertThe purpose of the Excessive Descent Rate (EDR) alert is to providenotification when the aircraft is determined to be descending upon terrain at anexcessive rate. The parameters for the alert as defined by TSO-C151b are shownbelow. "PULL UP""PULL UP""SINK RATE"$ESCENT 2ATE Height Above Terrain (Feet)Figure 11-12 Excessive Descent Rate Alert Criteria11.3.8.3 Forward Looking Terrain AvoidanceReduced Required Terrain Clearance (RTC) and Reduced RequiredObstacle Clearance (ROC) alerts are issued when the aircraft flight path isabove terrain, yet is projected to come within the minimum clearance values inthe FLTA Alert Minimum Terrain and Obstacle Clearance Values table. When anRTC alert and/or a ROC is issued, a potential impact point is displayed on theTAWS Page.Imminent Terrain Impact (ITI) and Imminent Obstacle Impact (IOI)alerts are issued when the aircraft is below the elevation of a terrain or obstaclecell in the aircraft’s projected path. ITI and IOI alerts are accompanied by apotential impact point displayed on the TAWS Page. The alert is annunciatedwhen the projected vertical flight path is calculated to come within minimumclearance altitudes in the following table.
