Garmin GTN 650Xi Series Pilot's Manual page 431

Altitude VCO
TAWS-B provides aural advisory alerts as the aircraft descends, beginning at 500 feet
above the terrain, as determined by the radar altimeter (if greater than 5 NM from
the nearest airport) or 500 feet above the nearest runway threshold elevation (if less
than 5 NM from the nearest airport). Upon descent to this altitude, TAWS-B issues
the aural alert message "Five-hundred."
TAWS-B Not Available Alert
TAWS-B requires a 3D GPS position solution along with specific vertical accuracy
minimums. Should the position solution become degraded or if the aircraft is out of
the database coverage area, the annunciation "TAWS N/A" is generated in the
annunciation window and on the TAWS-B page. The aural message "TAWS Not
Available" is generated. When the GPS signal is re-established and the aircraft is
within the database coverage area, the aural message "TAWS Available" is
generated (when the aircraft is airborne).
TAWS-B Failure Alert
TAWS-B 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 a "TAWS FAIL"
annunciation.
TAWS-B SYSTEM STATUS
During power-up, TAWS-B conducts a self-test of its aural and visual annunciations.
The system test can also be manually initiated. An aural alert is issued at test
completion. TAWS System Testing is disabled when ground speed exceeds 30 knots.
ANNUNCIATION
None
None
190-02327-03 Rev. C
ALERT TYPE
TAWS Available
TAWS System Test
in Progress
TAWS System Test Pass
TAWS N/A
TAWS Alerting is Disabled
TAWS System Test Fail
Pilot's Guide
Hazard Awareness
AURAL MESSAGE
"TAWS Available"
None
"TAWS System Test OK"
"TAWS Not Available"
None
"TAWS System Failure"
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