Garmin GNS 530W, Pilot'S Manual & Reference

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2 - NAV PAGES
49
Forward Looking Terrain Avoidance
The Forward Looking Terrain Avoidance alert, or
FLTA, is used by the TERRAIN system and is com-
posed of two elements:
Reduced Required Terrain Clear-
ance (RTC) Avoidance and
Imminent Terrain Impact
(ITI) Avoidance.
RTC/ITI TERRAIN Severity Levels
“TERRAIN AHEAD” alert (flashing)—Estimated
potential impact in approximately 30 seconds
after pop-up alert and annunciation. Similarly, an
“OBSTACLE AHEAD’’ alert is also provided.
“TERRAIN ADVISORY” advisory—Estimated
potential impact in approximately 60 seconds
after pop-up alert and annunciation. Similarly, an
“OBSTACLE ADVISORY” alert is also provided.
• Reduced Required Terrain Clearance (RTC) Avoidance
— Provides alerts when the aircraft flight path
is above terrain, yet is projected to come within
minimum clearance values outlined in the fol-
lowing Minimum Terrain Clearance Values table.
When an RTC alert is issued, a potential impact
point is displayed on the TERRAIN Page as shown
in the previous Terrain Altitude/Color figure.
• Imminent Terrain Impact (ITI) Avoidance
— Pro-
vides alerts when the aircraft is below the eleva-
tion of a terrain cell in the aircraft’s projected path.
ITI alerts are accompanied by a potential impact
point displayed on the TERRAIN Page. The alert
is given when the projected vertical flight path
is calculated to come within minimum clearance
altitudes in the following table.
Phase of Flight Level Flight Descending
En Route 700 ft. 500 ft.
Terminal 350 ft. 300 ft.
Approach 150 ft. 100 ft.
Departure 100 ft. 100 ft.
Minimum Terrain Clearance Values for RTC/ITI Alerts
During the final approach phase of flight, RTC/ITI
alerts are automatically inhibited when the aircraft
is below 200 feet AGL while within 0.5 NM of the
approach runway or is below 125 feet AGL while
within 1 NM of the runway threshold.
Terrain Alerts