Garmin GNS 530 - Manual (Page 205)

GNS 530(A) Pilot’s Guide and Reference 190-00181-00 Rev. H 13-1
SECTION 13
TAWS
SECTION 13: TAWS
NOTE: GNS 530 units may* display either a
TERRAIN Page or a TAWS Page, (but not both)
depending upon the installed hardware and
configuration.
* Some earlier units are not equipped to support the
TERRAIN and/or TAWS functionality, so therefore will not
have a TERRAIN or TAWS page available.
13.1 INTRODUCTION
TAWS (Terrain Awareness and Warning System) is
a feature to increase situational awareness and aid in
reducing controlled flight into terrain (CFIT). TAWS
satisfies TSO-C151b Class B requirements for certification.
Class B TAWS is required for all Part 91 aircraft operations
with six or more passenger seats and for Part 135 turbine
aircraft operations with six to nine passenger seats (FAR
Parts 91.223, 135.154).
TAWS functionality is an available feature found in
GNS 530 TAWS units with main software version 6.01 or
above, along with appropriate hardware upgrades. TAWS
provides visual and aural annunciations when terrain and
obstacles are within the given altitude threshold from the
aircraft.
Operating Criteria
TAWS requires the following to operate properly:
• The system must have a valid 3-D GPS position
solution.
• The system must have a valid terrain/obstacle/
airport terrain database.
Limitations
NOTE: The data contained in the TAWS databases
comes from government agencies. Garmin
accurately processes and cross-validates the
data but cannot guarantee the accuracy and
completeness of the data.
TAWS displays terrain and obstructions relative to the
altitude of the aircraft. The displayed caution and warning
alerts are advisory in nature only. Individual obstructions
may be shown if available in the database. However, all
obstructions may not be available in the database and
data may be inaccurate. Never use this information for
navigation or to maneuver to avoid obstacles.
Terrain information is based on terrain elevation
information in a database that may contain inaccuracies.
Terrain information should be used as an aid to situational
awareness. Never use it for navigation or to maneuver to
avoid terrain.
TAWS uses terrain and obstacle information supplied
by government sources. The data undergoes verification
by Garmin to confirm accuracy of the content, per TSO-
C151b. However, the displayed information should never
be understood as being all-inclusive.
TAWS Alerting
TAWS uses information provided from the GPS receiver
to provide a horizontal position and altitude. GPS altitude
is derived from satellite measurements. GPS altitude is
converted to a mean sea level (MSL)-based altitude (GPS-
MSL altitude) and is used to determine TAWS alerts.
GPS-MSL altitude accuracy is affected by factors such
as satellite geometry, but it is not subject to variations in
pressure and temperature that normally affect pressure
altitude devices. GPS-MSL altitude does not require local
altimeter settings to determine MSL altitude. Therefore,
GPS altitude provides a highly accurate and reliable MSL
altitude source to calculate terrain and obstacle alerts.