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190-01115-01
G3X/G3X Touch Installation Manual - Installation Preparation
Rev. AC
Page 2-4
NOTE
GDU 37X and GDU 4XX displays may not be combined in the same system.
A G3X system can have up to two G5 standby flight displays. For G5 installation information, refer to the
G5 installation/operation manual (190-02072-00).
GDU displays communicate with other LRUs via the CAN bus (with optional RS-232 backup paths
supported for some LRUs) and with other devices via RS-232.
A single GDU display, installed without any other G3X system components, may be configured as a
standalone MFD. A standalone MFD does not support flight instruments or advanced interface
capabilities, and is intended for applications where only basic mapping and navigation features are
required.
2.1.1.2 ADAHRS
The GSU 25 is the ADAHRS (air data, attitude, and heading reference system) unit for the G3X system.
An ADAHRS senses the aircraft’s attitude, measures all air data parameters, and calculates aircraft
heading.
A minimum of one ADAHRS unit is required, and up to three units are supported. In a system with
multiple GDU displays and multiple ADAHRS units, each display can present data from a separate
ADAHRS, and any GDU display may also be switched to display data from any ADAHRS. Data from
multiple ADAHRS units is also automatically cross-compared, and disagreements are noted on the PFD
display.
Each GSU 25 ADAHRS is connected to pneumatic pressure inputs for pitot, static, and angle of attack
(AOA). For aircraft capable of indicated airspeeds greater than 300 knots, the GSU 25B is used.
The GSU 25 communicates with other LRUs via the CAN bus, and can optionally be connected to the
PFD1 GDU via RS-232 for redundancy. For GSU 25 installation information, refer to
.
The older GSU 73 ADAHRS is also supported. The GSU 73 does not provide AOA data, but a system that
includes a GSU 73 may also include additional GSU 25 units. For GSU 73 installation information, refer to
.
In a system with one or more G5 standby flight displays, attitude and air data from the G5 will also be
displayed on the GDU displays, in the event that valid data is not available from any dedicated ADAHRS
unit.
2.1.1.3 Magnetometer
The G3X system requires a minimum of one magnetometer (magnetic field sensor) to provide the
ADAHRS unit(s) with magnetic field information. In an installation with multiple ADAHRS units,
magnetometer data is shared via the CAN bus. Additional magnetometers may be installed for
redundancy, although this is not commonly done. Several different magnetometers are supported:
The GMU 11 magnetometer connects to the G3X system via the CAN bus. Refer to
GMU 11 installation information. The GSU 73 does not support the GMU 11.
The GMU 22 magnetometer connects to the ADAHRS LRU via RS-232 and RS-485 interfaces. Refer to
for GMU 22 installation information. The GMU 44 is also supported and is functionally
identical to the GMU 22.
Refer to
for magnetometer placement information.