G1000 / GFC 700 System Maintenance Manual - 300/B300 Series King Air
Page 5-21
190-00716-01
Revision 1
Invalid Data Field
Associated
LRU(s)
Solution
HDG FAIL
GRS 77
&
GMU 44
•
Ensure metal objects (tool boxes, power carts, etc.)
are not interfering with the magnetometer and aircraft
is not in hangar, near other buildings, parked over
metal drainage culverts or on hard surfaces that may
contain steel reinforcements
•
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.
•
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,
•
Load configuration files to the PFD1, PFD2, GIA1,
and GIA2
9
If problem persists replace the GMU 44.
9
If problem persists, replace the GRS 77.
GRS 77
&
GMU 44
•
If this message persists longer than five minutes,
perform AHRS calibration procedures as described in
Section 7.7.3.
Summary of Contents for Cessna Caravan G1000
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