Gmu 44 Magnetometer - Garmin G1000 System Maintenance Manual

6.9

GMU 44 Magnetometer

The GMU 44 magnetometers may be located in the tailcone or in the horizontal
stabilizer.
Always use a non-magnetic Phillips screwdriver when removing or installing all screws
near the magnetometers.
Reference the "Magnetometer Install" and "Wire Harness Installation, Tail" drawings
listed in Table 1-2 for more details.
For Tailcone Location:
Removal:
1. Disconnect electrical wiring harnesses and remove the tailcone.
2. Remove three screws connecting the unit to the aircraft mounting bracket.
3. Remove the cable tie attaching the magnetometer pigtail harness to the shelf.
Reinstallation:
1. Visually inspect the connectors to ensure there are no bent or damaged pins. Repair any damage.
2. Fasten the GMU to the aircraft mounting bracket.
3. Attach the magnetometer pigtail harness to the shelf with a cable tie
4. Reinstall tailcone and connect the electrical wiring harnesses.
5. Calibrate and test the GMU 44 according to Section 7.7.
For Horizontal Stabilizer Location (left or right side):
Removal:
1. Remove inspection access panel (second from inboard) from lower side of the horizontal
stabilizer to gain access to the GMU electrical wiring harness.
2. Disconnect GMU pigtail harness from the electrical wiring harness.
3. Remove the screws and flux valve access cover from the upper side of horizontal stabilizer.
4. Mark the orientation of the GMU adapter plate assembly to the flux valve mounting dish.
5. Remove three screws/washers connecting the GMU adapter plate assembly to the flux valve
mounting dish.
6. Remove three screws connecting the GMU to the GMU adapter plate assembly.
7. If the unit is to be replaced, remove cable ties attaching the phenolic wire guard to the unit and
retain the wire guard and grommet from the pigtail harness.
Reinstallation:
1. Visually inspect the connectors to ensure there are no bent or damaged pins. Repair any damage.
2. Reinstall the three screws attaching the GMU to the GMU adapter plate assembly.
3. If a new GMU is installed, use two MS3367-7-1 cable ties through the retained phenolic wire
guard to secure the guard and connector harness to the GMU.
4. Ensure the MS35489-4 grommet is installed on the unit pigtail harness and secured in the slot in
the aft side of the GMU adapter plate assembly.
5. Use the orientation marks on the GMU adapter plate assembly to align the adapter plate assembly
to the flux mounting dish and reinstall the three screws/washers attaching the adapter plate.
6. Ensure there is a gap of at least 0.2 inch between the unit pigtail harness and the flux valve access
cover.
Page 6-6
Revision 4
NOTE
G1000 / GFC 700 System Maintenance Manual - 300/B300 Series King Air
190-00716-01