System Maintenance Manual

Page 7-26 G1000/GFC700 System Maintenance Manual – C90A/C90GT/C90GTi King Air
Revision F 190-00682-01
7.7 GRS 77 AHRS / GMU 44 Magnetometer
Original GRS 77 is Reinstalled
If the original GRS 77 was reinstalled, then no software loading is required. This does not include units
that were returned for repair as their software and configuration files are deleted during the repair testing
process.
If the GRS rack was not removed or loosened, continue to the GRS/GMU Test (Section 7.7.6).
If the GRS rack was removed or loosened, continue to the GRS/GMU Calibration Procedures (Section
7.7.1).
Original GRS 77 Installed in Opposite Locations for Troubleshooting
If the original GRS #1 and GRS #2 are installed in opposite locations (GRS #1 and GRS #2 in opposite
unit racks), no software loading is required.
If the GRS rack(s) was not removed or loosened, continue to the GRS/GMU Test (Section 7.7.6).
If the GRS rack(s) was removed or loosened, continue to the GRS/GMU Calibration Procedures (Section
7.7.1).
New Repaired or Exchange GRS 77 is Installed
If the repaired or exchange GRS 77 was replaced with a new unit then software must be loaded and the
unit must be calibrated. Continue to Section 3.9 for software loading. Then, proceed as follows:
If the GRS rack(s) was not removed or loosened, continue to the GRS/GMU Test (Section 7.7.6).
If the GRS rack(s) was removed or loosened, continue to the GRS/GMU Calibration Procedures (Section
7.7.1).
New GRS 77 Configuration Module is Installed
If the GRS 77 configuration module was replaced, no software loading is required. Continue to the
GRS/GMU Calibration Procedures (Section 7.7.1).
Original GMU 44 is Reinstalled
If the original GMU 44 was reinstalled, then no software loading is required. This does not include units
that were returned for repair as their software and configuration files are deleted during the repair testing
process. Continue to the GRS/GMU Test (Section 7.7.6).
Original GMU 44 Installed in Opposite Locations for Troubleshooting
If the original GMU #1 and GMU #2 are installed in opposite locations (GMU #1 and GMU #2 in
opposite unit racks), no software loading is required. However, performing the Magnetometer Calibration
Procedure is required. Continue to the GRS/GMU Test (Section 7.7.6).
New Repaired or Exchange GMU 44 is Installed
If the repaired or exchange GMU 44 was replaced with a new unit then software must be loaded.
Continue to Section 3.9 for software loading. Then continue to the GRS/GMU Calibration Procedures
(Section 7.7.1).