Garmin G1000 Pilot's Manual page 28

SYSTEM OVERVIEW
AHRS Normal
Operation
GPS INPUT FAILURE
In-flight initialization of AHRS, when operating without any valid source of GPS data and at true
NOTE:
air speed values greater than approximately 200 knots, is not guaranteed. Under these rare conditions, it
is possible for in-flight AHRS initialization to take an indefinite amount of time which would result in an
extended period of time where valid AHRS outputs are unavailable.
Two GPS inputs are provided to the AHRS. If GPS information from one of the inputs fails, the AHRS uses
the remaining GPS input and an alert message is issued to inform the pilot. If both GPS inputs fail, the AHRS
can continue to provide attitude and heading information to the PFD as long as magnetometer and airspeed
data are available and valid.
MAGNETOMETER FAILURE
If the magnetometer input fails, the AHRS continues to output valid attitude information; however, the
heading output on the PFD is flagged as invalid with a red 'X'.
AIR DATA INPUT FAILURE
Failure of the air data input has no affect on the AHRS output while AHRS is receiving valid GPS
information. Invalid/unavailable airspeed data in addition to GPS failure results in loss of all attitude and
heading information.
1-16
GPS
Magnetometer
Airspeed Data
AHRS no- AHRS no-Mag/
Mag Mode no-Air Mode
Heading Invalid
Figure 1-11 AHRS Operation
Garmin G1000 Pilot's Guide for Cessna Nav III
AHRS
no-GPS
Attitude/Heading Invalid
Mode
190-00498-01 Rev. A