Grs/Gmu Test; Grs 77 Earth Magnetic Field Updates - Garmin G1000 Maintenance Manual

2. Leave the Navigation lights on for approximately 10 seconds, and then turn them off.
3. Wait approximately five seconds and then press the ENT key to complete the test.
4. The PFD informs the operator if the installation has passed or failed the magnetometer interference
test. If the test passes, no further action is required.
5. Press the ENT key on the PFD to conclude this procedure.
6. If the MAG INTERFERENCE TEST fails but ALL of the deviations are less than the following
thresholds (X < 5 mGauss, Y < 5mGauss, and Z < 8 mGauss), the installation must be verified with a
flight test before it is acceptable.
If failures are indicated, the magnetometer interference test may be repeated at most
twice. If the test shows an X or Y deviation greater than or equal to 6 mGauss, or a Z
deviation greater than or equal to 10 mGauss after three attempts, then the installation
should not be considered reliable until the source of the interference problem is identified
and remedied. In the event of repeated failure of the magnetometer interference test,
record the values that are reported to be greater than or equal to 6 mGauss for future
reference.

6.7.5 GRS/GMU Test

The aircraft can now be taxied back and the engine can be shut down for final checkout.
When the PFD powers up in normal mode, the AHRS attitude and heading information displayed should
become valid within 1 minute of power-up. This confirms that the GRS 77 and GMU 44 work correctly.
If no other service is to be performed, continue to the return-to-service checks in Section 7.

6.7.6 GRS 77 Earth Magnetic Field Updates

The GRS 77 utilizes an Earth magnetic field model which is updated once every five years. The update is
expected to be available from Garmin in each of the following years: 2010, 2015 and every five years
thereafter, so long as the GRS 77 remains a Garmin-supported product.
The G1000 system alerts the operator that the magnetic field database is out of date by issuing the
message "AHRS SERVICE – AHRS Magnetic-field model needs update" (Reference Section Common
Alerts 4.9.3). Contact Garmin for update instructions.
G1000-Columbia 350/400 System Maintenance Manual
190-00577-03
NOTE
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Revision C