Figure 2-12, Ahrs - Garmin G1000 Nxi System Maintenance Manual

Attitude & Heading Reference System (2) (optional)
The optional Garmin GRS 77 AHRS or GRS 7800 AHRS units may be installed along with ADC
units in lieu of GSU 75B(s). They 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 Garmin Air Data Computers 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 1050As and GIA
63Ws. The GRS interfaces with and provides power to the GMU 44 Magnetometer. The GRS
supplies attitude and heading information directly to the PFDs, MFD, and GIAs. The #2 GRS
AHRS units can provide heading data to an approved third party TCAS II device through an
ARINC 429 digital interface.
Additionally, the GRS 7800 AHRS provides heading with or without the aiding of the Garmin
GMU 44 magnetometer. When operating without the aid of the magnetometer, the GRS 7800 is
functionally similar to that of a Directional Gyro.
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.
GRS 77 GRS 7800

Figure 2-12, AHRS

G1000 NXi System Maintenance Manual Page 16
King Air 300 Series Revision 1
190-00716-N1