EAA Sport Aviation

maker because of the millions of consumer GPS devices it has designed and built. The company had already announced touch-screen control systems for its turbine-level avionics systems that will be in the HondaJet and an Embraer business jet, so it was easy to see where the company was headed with avionics control and input technology. Despite its success making touch-screen GPS navigators for everyone from drivers to joggers, airplanes are different, and the design and implementation of touch screen for cockpit use needed to be perfected. Garmin has spent the past several years experimenting and testing touch-screen controls for the GTN series, and that investment has paid off.

I found it to be not only
easy but also natural to
use the touch screens.

Though Garmin had given me confidential briefings on the GTN development over the past few years and I got to operate prototypes, I still wondered how well the touch screen mounted in a vertical instrument panel would work in actual flight. Back in the 1970s and early ’80s both King Radio and Collins went down in flames with keyboard avionics control systems that were mounted in vertical panels. It was just too hard to find and press the desired buttons in turbulence. The FMS keyboards in turbine airplanes work fine because they are mounted horizontally in the pedestal between the seats, or on tilt panels that allow you to rest your palm on the bezel while pressing the keys with your fingers. But would the vertical mounting in GA airplane instrument panels work?

TOUCH-SCREEN TECHNOLOGY

After flying the GTN 750 and 650 in Garmin’s Mooney Ovation I can emphatically tell you that my fears were totally unfounded. I found it to be not only easy but also natural to use the touch screens for all data entry and mode selections. Garmin has built in finger grips on the display bezel

PHOTOGRAPHY COURTESY GARMIN AVIONICS

so you can use a thumb and finger to steady your hand, but I never felt the need to use them. Tapping the screen with my finger, even in some turbulence, was no problem. It took a few tries to figure out just how much pressure the screen responds to best, but by the time we landed after an hour or so of IFR flight, I felt perfectly at home using the new systems.

Like smartphones and many other touch-screen electronics, the GTN responds to moving your finger across the screen in addition to pressing on a “button.” If you want to pan the moving map, for example, simply slide your finger in the direction you want to go and the screen moves. You do the same for moving up or down in a menu. The operation is perfectly intuitive, and enough finger movement is required so that the display doesn’t jump quickly but changes smoothly.

The touch-screen technology Garmin used in the GTN is the pressure-sensitive type rather than the capacitance type found in many smartphones and tablets. It takes a little firmer touch to operate the GTN than some touch screens you may be using, but I found that to be a good thing because there is less chance of getting a “double hit” or making some unintended entry.

FEATURES

A big reason the GTNs are so easy to use is the effective menu design. The menus are short, and on the 750 with its greater size, the item you want is usually no more than a second press away. For example, to enter a new frequency, simply tap the standby frequency at the top of the display and a big keypad appears. Touch the numbers of the new frequency—and the numbers are really big on the 750 so even fat fingers don’t miss—and one more tap sends the new frequency into the standby window. To transfer the frequency to active, all it takes is a touch of the frequency.

Even though the touch screen is easy to operate the GTN series retained a twist knob to enter data. If the bumps are too bad to use the touch screen you always have the knob to hang onto.

At their heart, the GTN series are WAAS-capable GPS navigators combined with

The GTN 750 is double the size of the GNS 530. The extra display size allows it to be a full multi-function display showing IFR charts, airport diagrams, XM Weather, traffic, terrain, and moving maps.