Terrain - Garmin GI 275 Pilot's Manual

Hazard Avoidance

5.4 TERRAIN

WARNING: Do not use Terrain information for primary terrain avoidance. Terrain
information is intended only to enhance situational awareness.
NOTE: Terrain data is not displayed when the aircraft is outside of the installed terrain
database coverage area.
NOTE: Terrain and obstacle alerting is not available north of 89º North latitude
and south of 89º South latitude. This is due to limitations present within the Terrain
database and the system's ability to process the data representing the affected areas.
NOTE: No terrain or obstacle alerting occurs if Terrain Proximity is the only terrain
function configured.
The following terrain configurations are allowed:
Terrain Function
(H) Terrain Proximity
(H) Terrain-FLTA
External TAWS-B/
HTAWS Interface
Other external TAWS
The following is required for proper terrain display operation:
• Valid 3-D GPS position
• Valid terrain and obstacle databases
A GPS source is used to receive a horizontal position and altitude with terrain data. GPS
altitude is derived from satellite measurements. GPS altitude is then converted to the height
above geodetic sea level (GSL), which is the height above mean sea level (MSL) calculated
geometrically. GSL altitude is used to determine terrain alerts (if configured). GSL altitude
accuracy is affected by satellite geometry but is not subject to variations in pressure and
temperature that normally affect pressure altitude sensors. GSL altitude does not require
local altimeter settings to determine MSL altitude. It is a widely-used MSL altitude source.
Therefore, GSL altitude provides a highly accurate and reliable MSL altitude source to calculate
terrain and obstacle alerts.
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Displays relative terrain and obstacle data.
Displays relative terrain and obstacle data and provides aural and visual alerts
for potential flight path conflicts involving terrain or obstacles
External TAWS-B/HTAWS system provides terrain data and alerts which can be
displayed on the MFI
See the pertinent flight manual for the external TAWS equipment
Terrain Configurations
Garmin GI 275 Pilot's Guide
Description
190-02246-01 Rev. L