11-16GTN 725/750 Pilot’s Guide 190-01007-03 Rev. CForewordGettingStartedAudio &Xpdr CtrlCom/NavFPLDirect-ToProcChartsWpt InfoMapTrafflcTerrainWeatherNearestServices/MusicUtilitiesSystemMessagesSymbolsAppendixIndexFlight Phase Minimum Clearance Altitude (feet)Level Flight DescendingEn Route 700 500Terminal 350 300Approach 150 100Departure 100 100Table 11-4 FLTA Alert Minimum Terrain and Obstacle Clearance ValuesDuring final approach, FLTA alerts are automatically inhibited when theaircraft is below 200 feet AGL while within 0.5 NM of the approach runway orbelow 125 feet AGL while within 1.0 NM of the runway threshold.11.3.8.4 Premature Descent AlertingA Premature Descent Alert (PDA) is issued when the system detects that theaircraft is significantly below the normal approach path to a runway.PDA alerting begins when the aircraft is within 15 NM of the destinationairport and ends when the aircraft is either 0.5 NM from the runway thresholdor is at an altitude of 125 feet AGL while within 1.0 NM of the threshold. Duringthe final descent, algorithms set a threshold for alerting based on speed, distance,and other parameters.700600500400300200100Height Above Terrain (Feet)Distance From Destination Airport (nm)1 2 3 4 5 6 7 8 9 10 11 12 13 14 15PDA Alerting AreaPDA Alerting AreaRunwayThresholdFigure 11-13 PDA Alerting ThresholdPDA and FLTA aural and visual alerts can be manually inhibited. Discretionshould be used when inhibiting TAWS and the system should be enabled whenappropriate. When TAWS is inhibited, the alert annunciation “TER INHB” isshown.
