Taws-A System Status - Garmin GTN 625 Pilot's Manual

10.6.5
Foreword
During power-up, TAWS-A conducts a self-test of its aural and visual
Getting
annunciations. The system test can also be manually initiated. An aural alert
Started
is issued at test completion. TAWS-A System Testing is disabled when ground
Audio &
speed exceeds 30 knots.
Xpdr Ctrl
10.6.6
Com/Nav
TAWS-A continually monitors several system-critical items such as database
FPL
validity, flap and landing gear position, radar altimeter input, and GPS status.
If the GTN does not contain Terrain, Airport Terrain, and Obstacle databases
Direct-To
(or the databases are invalid), the aural message "TAWS System Failure" is
generated along with the "TAWS FAIL" alert annunciation.
Proc
TAWS-A requires a 3-D GPS navigation solution along with specific vertical
Wpt Info
accuracy minimums. Should the navigation solution become degraded or if
the aircraft is out of the database coverage area, the annunciation "TAWS N/A"
Map
is generated in the annunciation window and on the TAWS-A page, the aural
message "TAWS Not Available" is generated if airborne, some TAWS-A terrain
Traffic
alerts will not be issued, and GPWS alerting (which are not dependent on GPS
position) will continue to operate. When the GPS signal is re-established and the
Terrain
aircraft is within the database coverage area, the aural message "TAWS Available"
is generated.
Weather
TAWS-A also requires radar altimeter input. Should the radar altimeter input
Nearest
fail or become degraded, the annunciation "GPWS FAIL" is generated in the
annunciation window and on the TAWS-A Page. The aural message "GPWS
Services/
Music
System Failure" is also generated. The "GPWS FAIL" annunciation will also occur
if both GPS altitude and barometric altitude are unavailable. If only the GPWS
Utilities
system has failed, GPWS-based alerts will not be available, while other TAWS-A
alerting remains unaffected.
System
Multiple TAWS or GPWS annunciations cannot be displayed at the same
Messages
time. When multiple annunciations exist, an asterisk will be present next to the
annunciation. The display of each annunciation will alternate with each being
Symbols
displayed for approximately five seconds.
Appendix
Index
10-60

TAWS-A System Status

TAWS-A Abnormal operations
Garmin GTN 625/635/650 Pilot's Guide 190-01004-03 Rev. K