The Garmin GTN 750 Nav/Com is a heavy unit and the tray has to be securely mounted to the instrument panel. It is also deep and has to penetrate through the center sub-panel. In order to locate the hole for the tray, I have to mount the tray in the instrument panel to locate the hole location in the center sub-panel. The panel center stack has the Garmin GMA-350c audio panel at the bottom. Then the GTN750 and on the top the Garmin GFC 500 autopilot control head. I started by mounting the audio panel tray at the bottom first according to the instructions in the installation manual. Next I installed the GTN750 tray in accordance with its installation manual. I fabricated a couple of supports between the audio panel tray and the GTN750 tray. I deburred and primed the supports. Last I installed the autopilot control head at the top. Now I am ready to install the panel and locate the hole location in the sub-panel.
