Garmin G1000 Series, Pilot'S Manual

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190-00592-00 Rev. A
Garmin G1000 Pilot’s Guide for the Diamond DA40
1-13
SYSTEM OVERVIEW
AHRS MODES OF OPERATION
The GRS 77 Attitude and Heading Reference
System (AHRS) performs attitude, heading, and
vertical acceleration calculations for the G1000 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 (see Figure 1-8).
Loss of GPS, Magnetometer, or air data inputs is
communicated to the pilot by message advisory alerts.
Any failure of the internal AHRS inertial sensors results
in loss of attitude and heading information (as indicated
by red ‘X” flags over the corresponding flight instruments
on the PFD).
NOTE: Refer to the Annunciations and Alerts
section for specific AHRS alert information.
Attitude/Heading Invalid
av
ail
ab
le
una
vail
able
AHRS
no-GPS
Mode
AHRS Normal
Operation
Airspeed Data
av
ail
ab
le
una
vail
able
AHRS no-Mag
Mode
AHRS no-Mag/
no-Air Mode
Heading Invalid
av
ail
ab
le
una
vail
able
av
ail
ab
le
una
vail
able
av
ail
ab
le
una
vail
able
GPS
Magnetometer
Figure 1-8 AHRS Operation
GPS Input Failure
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 effect 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.
NOTE: Aggressive maneuvering
while AHRS is not operating
normally may degrade AHRS
accuracy.