Garmin GPS 500 Pilot's Manual & Reference page 182

SECTION 11
TAWS
Table 11-3 shows system status annunciations that may also be issued:
Alert Type
TAWS System Test Fail
TAWS Alerting is disabled
No GPS position or excessively degraded
GPS signal
System Test in progress
System Test pass
Forward Looking Terrain Avoidance
The Forward Looking Terrain Avoidance (FLTA) alert is used by TAWS and is composed of:
• Reduced Required Terrain Clearance (RTC) and Reduced Required Obstacle Clearance (ROC) -These alerts are
issued when the aircraft flight path is above terrain, yet is projected to come within the minimum clearance
values in Table 11-4. When an RTC or ROC alert is issued, a potential impact point is displayed on the TAWS
Page.
• Imminent Terrain Impact (ITI) and Imminent Obstacle Impact (IOI) - These alerts are issued when the
aircraft is below the elevation of a terrain or obstacle cell in the aircraft' s projected path. ITI and IOI alerts are
accompanied by a potential impact point displayed on the TAWS Page. The alert is annunciated when the
projected vertical flight path is calculated to come within minimum clearance altitudes in Table 11-4.
Phase of Flight
Approach
Departure
Table 11-4 Minimum Terrain and Obstacle Clearance Values for FLTA Alerts
During the final approach phase of flight, FLTA alerts are automatically inhibited when the aircraft is below 200
feet AGL while within 0.5 nm of the approach runway or below 125 feet AGL while within 1.0 nm of the runway
threshold.
11-6
TAWS Page
Annunciation
None
Table 11-3 Additional System Annunciations
Minimum Clearance
Altitude Level Flight (ft)
Enroute
Terminal
GPS 500 Pilot's Guide and Reference
Pop-Up Alert
None
None
None
"TAWS Available" is generated when sufficient
None
None
Minimum Clearance
Altitude Descending (ft)
700 500
350 300
150 100
100 100
Aural Message
"TAWS System Failure"
None
"TAWS Not Available"
GPS signal is re-established.
None
"TAWS System Test OK"
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