System Maintenance Manual

Page 2-6 G1000/GFC700 System Maintenance Manual – C90A/C90GT/C90GTi King Air
Revision G 190-00682-01
2.1.11 GMU 44 Magnetometer (2)
The GMU 44 provides horizontal and vertical magnetic field information to the GRS 77 AHRS. This allows
heading to be calculated and provides assistance during AHRS alignment. The GMU 44 units are mounted
in the vertical tail. The units receive power directly from the GRS 77 units and communicate with the GRS
77 units via RS-485 digital interface.
2.1.12 GDL 69A Datalink
The GDL 69A provides the interface to the GWX 68 weather radar by acting as a communications hub
between the MFD and GWX68 via HSDB. The GDL 69A also provides XM Radio weather and music
entertainment through means of a dedicated satellite data link. The GDL 69A is mounted behind the
instrument panel. Power to the GDL 69A is received from the avionics No. 3 bus. The GDL 69A sends
weather data through the HSDB bus to the MFD, where the data link interface is controlled. Digital audio is
sent directly to the GMA 1347D Audio Panel.
2.1.13 GWX 68 Weather Radar
The GWX 68 Airborne Weather Radar provides weather radar data output to the GDU 1500 MFD. The
GWX 68 is mounted forward of the forward bulkhead at F.S. 30. Power to the GWX 68 is received from the
avionics No. 2 bus. Data received from the GWX 68 is routed through the GDL 69A data link unit to the
MFD via high-speed data bus (Ethernet).