Garmin G1000 Maintenance Manual page 43

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System Annunciation Troubleshooting (continued)
Annunciation
HDG FAIL
G1000 System Maintenance Manual
190-00907-00
Associated
LRU
•
Check PFD Alert Window for PFD, MFD or GRS
configuration, software or failed data path error
messages. Correct any errors before proceeding.
•
Check for metal objects (tool boxes, power carts,
nearby large steel structures, etc.) around the
aircraft that could be interfering with the
magnetometer.
•
Ensure that a cell phone or a device using cell
phone technology is not turned on (even in a
monitoring state) in the cabin.
•
Cycle power after moving aircraft away from metal
objects to determine if metal objects were the
source of the interference. Allow up to five minutes
for the heading to reinitialize.
•
Is the aircraft stationary if GPS is not available?
Aircraft movement (rocking the wings or moving the
GRS 77 &
tail) may cause the attitude and heading to fail if it
GMU 44
believes the aircraft is in motion without GPS input.
•
Perform a Magnetometer Interference Test to check
for interference from onboard electrical system
components (e.g. NAV lights). Pay particular
attention to any new electrical devices that have
been installed since the aircraft was new. Correct
any discrepancies that do not allow this test to pass
before continuing.
•
Ensure GRS 77 and GMU 44 connectors are
secure.
•
Check the wiring and any inline connectors between
the GRS and GMU for faults.
•
Recalibrate the GMU 44.
•
Replace the GMU 44.
•
If problem persists, replace the GRS 77.
Solution
Page 5-7
Rev. B