Copyright © 2016  Grand Rapids Technologies, Inc.                      

Electronic Flight Instrumentation for Experimental Aircraft Since 1991

Manuals, templates and wiring diagrams are presented here for our EFIS and EIS systems.  All documents are in PDF format.  If you need a program to read PDF files, you may download it for free here.

Note: If you do not know which GRT system or which software version is installed in your aircraft, read the initial boot-up screen when you first power on the EFIS, before you press “ACCEPT”.  The model designation of the EFIS, along with the installed software revision, is displayed at the top of the page.

EFIS System Manuals

Horizon HXr

Horizon I HX/HS/WS



Engine Monitor (EIS) & Probes


GRT Autopilot Manuals

GRT External Modules (GPS, etc.)

Supplemental Avionics Manuals

How to connect your GRT EFIS to GPS navigators, remote transponders, etc.