Garmin PDAs & Smartphones G1000 User Manual

190-00498-07  Rev. A

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If a display fails, the appropriate IAU Ethernet interface to the display is cut off.  Thus, the IAU can no longer 

communicate with the remaining display (refer to Figure 1-1), and the NAV and COM functions provided to 
the failed display by the IAU are flagged as invalid on the remaining display.  The system reverts to backup 
paths for the AHRS, ADC, Engine/Airframe Unit, and Transponder, as required.  The change to backup paths is 
completely automated for all LRUs and no pilot action is required.

If the system fails to detect a display problem, reversionary mode may be manually activated by pressing 

the Audio Panel’s red DISPLAY BACKUP button (refer to the Audio Panel and CNS Section for further details).  
Pressing this button again deactivates reversionary mode.

Refer to Appendix A for specific AHRS alert information.

Aggressive maneuvering while AHRS is not operating normally may degrade AHRS accuracy.

The 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.

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 (indicated by red 
‘X’ flags over the corresponding flight instruments).