G300 System Annunciations; Ahrs Operation - Garmin G300 for Cessna SkyCatcher Pilot's Manual

System Overview

G300 SYSTEM ANNUNCIATIONS

When an LRU or an LRU function fails, a large red 'X' is typically displayed
over the instrument(s) or data experiencing the failure (Refer to Appendix E,
Abnormal Operation). Upon G300 power-up, certain instruments remain invalid
as equipment begins to initialize. All instruments should be operational within
one minute of power-up. If any instrument remains flagged, the G300 should be
serviced by an authorized repair facility.

AHRS OPERATION

The Attitude and Heading Reference System (AHRS) performs attitude,
heading, and vertical acceleration calculations for the G300 System, utilizing GPS,
magnetometer, and air data in addition to information from its internal sensors.
Attitude and heading information are updated on the PFD while the AHRS receives
appropriate combinations of information from the external sensor inputs.
The AHRS (GSU 73) corrects for shifts and variations in the Earth's magnetic field
by applying the Magnetic Field Variation Database. The Magnetic Field Variation
Database is derived from the International Geomagnetic Reference Field (IGRF).
The IGRF is a mathematical model that describes the Earth's main magnetic field
and its annual rate of change. The database is updated approximately every 5
years. Failure to update this database could lead to erroneous heading information
being displayed to the pilot. The database can only be updated by an authorized
Cessna Service Center.
14
PFD Initialization
Garmin G300 Pilot's Guide 190-00921-00 Rev. E