G1000 / GFC 700 System Maintenance Manual - 300/B300 Series King Air
Page 2-7
190-00716-01
Revision 1
2.1.10
GRS 77 Attitude & Heading Reference System (2)
The Garmin GRS 77 AHRS units provide attitude and heading information to the G1000 system. The units,
mounted in the nose equipment bay, contain advanced tilt sensors, accelerometers, and rate sensors. The
unit interfaces with the GDC 7400 and GMU44 Magnetometer and utilizes GPS signals from the GIA 63Ws.
Actual attitude and heading information is sent using ARINC 429 digital interface to both GDU 1040As and
GIA 63Ws. The GRS 77 interfaces with and provides power to the GMU 44 Magnetometer. The GRS 77
supplies attitude and heading information directly to the PFDs, MFD, and GIAs.
GRS 1 receives primary electrical power from No. 1 Triple Fed Bus and a secondary power supply from the
Center Bus. GRS 2 receives electrical power from No. 3 Triple Fed Bus.
Figure 2-10, AHRS
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 tailcone. The units receive power directly from the GRS 77 units and communicate with the GRS 77
units via RS-485 digital interface.
Figure 2-11, Magnetometer
Summary of Contents for Cessna Caravan G1000
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