Grs 77/Gmu 44 Related Alerts And Problems - Garmin G1000 Maintenance Manual

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5.7

GRS 77/GMU 44 RELATED ALERTS AND PROBLEMS

5.7.1 Common Problems
Symptom
AHRS does not complete
initialization
Attitude appears unstable
Page 5-52
Rev. B
Recommended Action
•
Ensure that a cell phone or a device using cell phone technology
is not turned on (even in a monitoring state) in the cabin.
•
Ensure GPS has acquired at least four satellites, has a 3D
navigation solution, and a DOP of less than 5.0. This is
particularly important if this issue appears during ground
operation only.
•
Calibrate the GRS 77.
•
Check GRS 77 configuration module wiring for damage.
•
Check GRS 77 connector for bent pins.
−
If no damage can be found, replace GRS 77 configuration
module.
•
If problem persists, replace the GRS 77.
•
Ensure that a cell phone or a device using cell phone technology
is not turned on (even in a monitoring state) in the cabin.
•
Ensure the four GRS 77 mounting screws are tight. Finger tight is
not sufficient, a screwdriver must be used to verify.
•
Ensure mounting rack and airframe shelf are secure and all
hardware and brackets are present (CAUTION - do not loosen the
mounting rack hardware to the airframe shelf or the aircraft will
need to be re-leveled and the PITCH/ROLL OFFSET procedure
performed).
•
Ensure GRS 77 connector is securely fastened and proper strain
relief is provided.
•
Remove GRS 77 connector and verify there are no bent pins.
•
Replace the GRS 77.
•
Contact Garmin for further troubleshooting if required.
G1000 System Maintenance Manual
190-00907-00