Altimeter (Gsl Backup); Vertical Speed Indicator (Vsi) - Garmin GI 275 Pilot's Manual

Flight Instruments

ALTIMETER (GSL BACKUP)

WARNING: Do not use geometric altitude for compliance with air traffic control
altitude requirements. The primary barometric altimeter must be used for compliance
with all air traffic control altitude regulations, requirements, instructions, and
clearances.
In the event of all static air data sources failing but GPS data is available, the 'ADI' Page can
display Geometric Sea Level (GSL) altitude as a backup altitude source. GSL altitude is derived
from GPS altitude. 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, thus the altimeter
setting field is disabled when using GSL altitude.
GSL Annunciation
Vertical Speed
Altimeter Setting

VERTICAL SPEED INDICATOR (VSI)

The Vertical Speed Indicator displays the aircraft vertical speed below the altimeter. The
indications are in thousands of feet per minute or in meters per second as configured by
the installer. A magenta Altitude Trend Vector extends up or down the right of the altitude
tape, the end resting at the approximate altitude to be reached in 6 seconds at the current
vertical speed. The trend vector is not shown if altitude remains constant or if data needed for
calculation is not available due to a system failure.
Vertical Speed Indicator
38
Indicator
(Disabled)
Altimeter displaying GSL
Vertical Speed Indicator and Altitude Trend Vector
Garmin GI 275 Pilot's Guide
GSL Altitude
(Magenta)
Altitude Trend Vector
190-02246-01 Rev. A