Revision A5 1-7
GRT Avionics HXr Installation Manual
SECTION 1: GENERAL DESCRIPTION
1.1 Introduction
This document provides the physical, mechanical and electrical characteristics and installation
requirements for the GRT HXr EFIS.
This document, the HXr Set Up Guide and the HXr Users Guide make up the set of HXr user
documentation. These documents, along with periodic software updates and other notices, are
available at www.grtavionics.com under the Support menu.
1.2 Certification
The GRT HXr EFIS is not certified for installation in FAA Type Certificated Aircraft. It is designed
and intended for installation in aircraft licensed as Experimental or Light-Sport.
1.3 System Description & Architecture
The GRT HXr EFIS (Electronic Flight Information System) consists of one or more panel mounted
Display Units, one or more remotely mounted attitude-heading reference system (AHRS), and one
or two remotely mounted magnetometers. The Display Unit is available with either a 10.4” or 12.1”
screen. Dimensional drawings for both sizes, as well as the AHRS and magnetometer, are provided
in the Appendix of this manual. The HXr is available as either a 12 or 28-volt system; the voltage
is specified on the data tag of the display unit.
Two AHRS packages are available. The Dual AHRS package (AHRS-2) is standard with the
dual-display system, while the single AHRS (AHRS-1) is standard with a single display. The Dual
AHRS is two identical AHRS units inside one module; this assures that both AHRS units are aligned
with each other at all times. Dual AHRS is available with a single screen system as an option.
The most basic configuration for HXr is a single EFIS screen to display the primary flight instruments
of airspeed, altitude, heading, attitude, vertical speed, and rate of turn. To do this, the EFIS display
unit works with a remotely-mounted attitude-heading reference system, or AHRS, and a
magnetometer unit to determine aircraft attitude and heading information. The air data computer,
located inside the AHRS box, is connected to the aircraft pitot/static system to determine airspeed
and altitude. The GRT AHRS is unique in the industry in that it provides attitude data without gyros,
GPS or pitot/static input to compute aircraft attitude, making it more reliable than systems that
require external data.
When GPS is added to the system, GPS track and a moving map are displayed on the map page
of the primary display or the secondary display if equipped. GRT offers several different GPS
modules for the HXr. A third-party GPS unit may also be used, such as a Garmin 430/530 or Garmin
650/750. This feature is useful for adding IFR GPS approach capability to the HXr system. (IFR
approach sequencing is currently in development at GRT.) Note that the only GPS functions that
