190-02246-11
GI 275 Part 23 AML STC Maintenance Manual
Rev. 1
Page 2-2
2.1 System Overview
The GI 275 installation can provide Primary ADI, HSI, MFD/Standby ADI, HSI/Standby ADI, MFD, and
EIS functions. Three unit variants are available: the baseline GI 275 Base, the GI 275 ADAHRS which
contains an integrated ADAHRS, and the GI 275 AP which includes the functionality of the
GI 275 ADAHRS but can also drive an approved autopilot. The GI 275 system utilizes engine sensors and
a GEA 24 or GEA 110 engine adapter to provide EIS functions.
System limitations are contained in Section 2 of the GI 275 installation manuals (refer to Table 1-1).
Model-specific limitations are contained in Appendix D of the GI 275 installation manuals. This
information includes specific installation limitations for type rated, commuter category/Class IV, as well as
Class I - III aircraft.
2.1.1 Primary ADI Functionality
The Primary Attitude Direction Indicator provides attitude, airspeed, altitude, and heading. The required
Primary ADI installation consists of:
• GI 275 ADAHRS or AP
• If configured for 3-in-1 ADI
◦ GTP 59 OAT Probe (optional for Class I & II aircraft)
◦ Internal or external WAAS GPS source
◦ Pitot-static connection
• Installed backup battery
2.1.2 HSI Functionality
The Horizontal Situation Indicator provides magnetically stabilized heading based on magnetometer data.
The HSI can provide course error and deviations to an autopilot if the GI 275 AP is used. The
required HSI installation consists of:
• GI 275 display (the GI 275 Base can be used if it receives AHRS from a GI 275 ADAHRS or
AP)
• ADAHRS capability, via internal ADAHRS (included with GI 275 ADAHRS and AP
variants)
• GMU 11 or GMU 44B Magnetometer
2.1.3 MFD/Standby ADI Functionality
The MFD/Standby ADI provides the same information as the Primary ADI, but can additionally display
information on pages similar to the MFD during normal operation. The standby indicator has the same
installation requirements as the GI 275 Primary ADI but with the additional requirement to install a
GTP 59, backup battery, and potentially a display backup switch. Refer to
GI 275 Part 23 AML STC
Installation Manual
for switch requirements.
2.1.4 HSI/Standby ADI Functionality
The HSI/Standby ADI provides the same information as the Primary ADI, but additionally displays HSI
information during normal operation. The standby indicator has the same installation requirements as the
GI 275 Primary ADI and GI 275 HSI but with the additional requirement to install a GTP 59, backup
battery, and a display backup switch. Refer to
GI 275 Part 23 AML STC Installation Manual
for switch
requirements.
