Garmin GPS 500 Pilot's Manual & Reference page 186

SECTION 11
TAWS
'FIVE-HUNDRED' AURAL ALERT
The purpose of the aural alert message "Five-Hundred"
is to provide an advisory alert to the pilot that the air-
craft is 500 feet above terrain. When the aircraft descends
within 500 feet of terrain, the aural message "Five-Hun-
dred" is generated. There are no display annunciations or
pop-up alerts that accompany the aural message.
TAWS NOT AVAILABLE ALERT
TAWS requires a 3-D GPS navigation solution along
with specific vertical accuracy minimums. Should the
navigation solution become degraded or if the aircraft is out
of the database coverage area, the annunciation 'TER N/A'
is generated in the annunciation window and 'TERRAIN
NOT AVAILABLE' is generated on the TAWS Page (Figure
11-10). The aural message "TERRAIN Not Available" is
generated. When the GPS signal is re-established and
the aircraft is within the database coverage area, the
'TER N/A' visual annunciation is removed (there is no
associated aural message).
Figure 11-10: TAWS NOT AVAILABLE Display
11-10
TAWS FAILURE ALERT
TAWS continually monitors several system-critical
items such as database validity, hardware status, and GPS
status. If the terrain/obstacle database is not available,
the aural message "TAWS System Failure" is generated
along with 'TER FAIL' in the annunciation window, and
'TERRAIN FAILED' on the TAWS Page (Figure 11-11).
GPS 500 Pilot's Guide and Reference
Figure 11-11: TAWS FAILED Display
190-00181-60 Rev. G