Garmin G1000 NAV III Line Maintenance Manual page 146

8. Press the ENT key.
9. Press the CLR ALL softkey.
10. Using the FMS knob select the following files:
•
GMU Software
Pressing the ENT key will check and uncheck the highlighted software and configuration boxes.
11. Once the desired files are selected press the LOAD softkey.
12. Verify the correct software part number and software version on the SYSTEM STATUS page.
For software/configuration troubleshooting see Section B.4, otherwise continue to Section 4.4.5.
4.4.5 GRS/GMU Calibration
G1000 Nav III System Software allows valid outputs from the AHRS, prior to completion of the
AHRS and magnetometer calibration procedures, as long as the GRS 77 can definitively
determine that the aircraft is not moving. This gives a technician the ability to perform functional
tests during aircraft assembly that require valid AHRS outputs. Additionally, a "CALIBRATE
AHRS/MAG" message will be displayed on the PFD until a successful magnetic calibration has
been completed.
The criteria used by the AHRS to determine the aircraft is moving are as follows:
1. If valid GPS data is available and each component of 3D GPS velocity is less than 4
knots, the aircraft is considered "not moving" and attitude/heading will become valid.
2. If valid 3D GPS data is not available, but valid true airspeed is less than 30 knots, the
aircraft is considered "not moving" and attitude/heading will become valid.
3. If both 3D GPS and true airspeed are unavailable, attitude/heading will not become valid.
No configuration is required for the GRS 77, unless the mounting bolts that secure the mounting rack are
loosened. If the mounting bolts are loosened a new post-installation calibration is required. Any GMU 44 that is
removed and/or replaced requires a magnetometer calibration.
There are six calibration procedures available:
•
Pitch/Roll Offset (Procedure A1)
•
Pitch/Roll Offset, Manual Entry (Procedure A2)
•
Magnetometer Calibration, (Procedure B)
•
Heading Offset Compensation, (Procedure C)
•
Engine Run-Up Vibration Test, (Procedure D)
•
Magnetometer Interference Test, (Procedure E)
Procedures A2 and C are not required and should not be performed on Nav III aircraft.
When ready to perform the procedures, shut the PFD and MFD off by pulling the PFD and MFD circuit breakers.
Restart both displays in configuration mode. Follow the steps given for each procedure on-screen at the
GRS/GMU CALIBRATION page. Note that the CALIBRATE command cannot be selected and activated until
the installer acknowledges all required steps have been carried out by pressing the ENT key on each step.
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G1000 Nav III Line Maintenance Manual
190-00352-00