In the 13 years since the GNS430 appeared-yes, 13 years-display, processor and GPS technology has all but reinvented itself and the new GTN boxes integrate those advances. They use a variant of the 5 Hz WAAS chip Garmin developed for the GNS430W/530W, but both the GTN650 and 750 have new, faster processors with more video capability. The displays remain the TFT technology thats now industry standard, but the resolution is higher. On the 650, its 600 by 266 pixels while the 750 has 600 by 708 pixels. Thats about a five-fold increase in pixel density. Both screens have 250,000-plus colors, the net effect of which is to render details such as terrain and weather in near-VGA crispness. Where the GNS530 goes blocky at the mid-range scales, the GTNs dont, although they do exhibit some refresh delay. Both of the new products support Garmins 9-arc second terrain capability. Side-by-side with the G600 EFIS, theyre not quite as photo-realistic, but the difference is subtle. Speaking of which, the G600 supports synthetic vision and we asked if the GTN 750 could. Garmins Jim Alpiser says thats unknown, so well take that as a maybe. Our impression is that it has a lot of hooks

for future development, even if it doesnt evolve into some kind of EFIS crossover mutant.

Sizewise, the displays are larger, although this is most noticeable when you look at the previous generation after using the GTNs. The 650s display is 53 percent larger on the same size overall box, while the 750 is an astonishing 98 percent larger in a unit whose display is 6 inches high compared to 4 inches for the GNS530. (The box itself is not as high as the display, providing space behind the display for a remote audio panel, thus freeing up panel space.)

Garmin gets kudos for not cluttering up these displays with a bunch of extraneous data and it deserves more credit for using them to maximize the size of the menu icons and buttons, something that the presbyopic crowd who can afford to buy these things will appreciate. Theyre sort of the Readers Digest large-print version of navigators.

If you were hoping these boxes might be pin-for-pin slide-in replacements for the 430 and 530, its not to be. They require their own dedicated trays, so installation will be a full-boat deal. However, you can retain the standard Garmin GMA35 antenna, since the new products will use these, too.

The most striking thing about the GTNs is how Garmin got the displays that large. They essentially shrunk the bezels down to the bare minimum by stripping the keys and reverting to a touch-screen driven operating system. Where the GNS430 has 16 buttons and knobs-18 if you count the concentric-the GTN650 has…four, one of which is a concentric. For a veteran 430 owner, this will be disconcerting at first. How the hell do you make this thing play? You need to know just one thing: Push the home key.

The entire operating system-almost-drives through the home key which, when pushed, pulls up a series of icons that paint a graphic interface glimpse into the boxes inner functions. Some of these step through to additional sub-choices. The only familiar dedicated key remaining is the direct-to key, a decision Garmin made because it knows that some users overarching knowledge of sophisticated GPS navigators consists entirely of jabbing the direct-to key. The rest of the functions lie unexposed to the light of intelligent life.

Will the menu-driven approach help that? If it doesnt, Garmin should add a feature to check the operator for a pulse. (Maybe a future software upgrade?) We werent able to do a function-by-function comparison of the GTNxs operating logic with the GNS series, but from what we did see, its an amalgam of the aera GUI-driven logic with vestiges of Garmins familiar operating system. For example, punching the direct-to key pulls up a screen populated by a waypoint subpage or list, just as with the 430/530.

At this point, you can either scroll in the waypoint you want with the concentric knob, which is soooo 1998, or touch the “select waypoint” icon and pull up a virtual keyboard to punch it in directly. Want to guess which is easier? On the 750, the key icons are large and you really have to be fat-fingered to miss a key. Theres no haptic or reiterative feedback, but the touchscreen uses capacitance sensing so its sensitivity is a little less (better) than a crappy smartphone, but not the touch-me-twice-please tendency of the resistance-based aera touchscreens.

On the 650, the overall screen size isnt large enough to accommodate a full A-Z touchpad, so the navigator displays the alphanumerics horizontally in a tape format, which you can finger slide to find the letters or-faster-pick a five-letter zone of desired letters from a compressed A-Z tape below the main tape slider. We didnt have enough time to compare the two keyboards in depth, but either is a vast improvement over knob scrolling. Also worth mentioning is that you can finger pan or scroll the screen at any time.

At this juncture, youre thinking…what about turbulence? How you gonna punch those keys in continuous moderate chop? Garmin thought of that and has molded raised lips into the sides of the bezels and a finger rail at the bottom. These serve as anchor points for your fingers or a thumb or whatever digit isnt doing the key punching. On our flight trial, we encountered some bumps at low altitude and tried this out. It seems to work, but its an acquired skill and Garmin test flight engineer Grant Wintenborn told us everyone does it differently.

For example, with your ring finger on the right bezel and your thumb on the left, you can peck away with your forefinger, but when you want to hit the back key in the extreme lower left of the screen, now what? Your thumb, thats what. First time, it takes a little hesitation to figure this out; second time, its more natural. Wider field experience will reveal the prehensile limits of the contemporary pilot. Well be standing by to see how users take to this.

And speaking of the back key, it brings the GUI logic you know from Web browsing into a cockpit navigator. By now, jabbing a back key when you screw something up is almost an autonomic function for the fully evolved man. So it is with the GTNxs. When you get used to the back key being lower left rather than upper left, backing out of miscommands is second nature.

The reason the back key isnt upper left is because the comm controls are up there on the GTN750. As it did with the 430/530, Garmin has integrated the comm control/display into the main display and without mincing words here, it works way

the hell better in the GTNs than it does in the G1000. Comm control is utterly intuitive and there are some nice add-on details.

The comm freqs appear on the top of the display on the 750, on the right on the 650, with the active frequency on top and standby on the bottom. To flip them, just touch the standby window and the two exchange position. Or you can punch the center concentric knob. To key in a freq, touch the standby window and you get a giant numeric keyboard to punch in the frequency you want.

Once youve done that, the frequency will be in the standby window. At the bottom of the screen, is the choice of “monitor” or “xfer.” The former allows you to monitor the frequency while having the other active while xfer immediately activates the frequency you just punched in. You can scroll the frequencies in using the inner knob-familiar, but slow.

Where the design inches into the pretty cool is the find function. Like the Macs Searchlight, punching the little magnifying glass symbol allows you to search for waypoints by type-recently used, VORs, name, by city and so forth. This function isnt new, but it works better than the previous variant did.

Integrated functions for the transponder and audio panel are similarly in the Goldilocks zone-just deep enough to be genuinely useful and practical, but not too

far out there as to pass into the look-how-%$#@-clever-I-am-navel-gazing realm of software features. The audio panel and intercom functions are especially well designed, offering an easy-to-figure-out capability to split mics, external inputs such as music, volume control via finger sliders and a built-in clearance recorder via the audio panel function. The GTN750 is designed to work with a new remote audio panel coming this year called the GMA35, but it will obviously tie into older audio panels, albeit without the integrated control through the navigator. The 650 doesnt have the remote audio capability.

Whats most intriguing here is that the audio panel will have voice recognition capability for basic commands and although Garmin didnt say as much, the navigator itself seems certain to eventually get that capability, too. (See sidebar above.)

Garmin has significantly improved the flight planning and charting functions in the GTN boxes. As with everything else, you enter the FP function through an icon on the homepage and the logic steps you through the options to add each waypoint, popping up the keyboard in context as required. The search function can be employed to find a fix or navaid. Airways are included, by numbered list, and the logic of entering or exiting these is easy to grasp.

But for those of us in a hurry-isnt that everyone?-the GTNs have a GUI rubberband feature. Heres how it works: If your course is depicted via the magenta line from A to B and you want to go via C, just touch the “graphically edit FPL” icon and drag the line where you want it and the line snaps to that point, automatically adding it to the flightplan list. But what if you move the line into a congested area on the map? How can you control where it snaps? Garmin thought of that, too. The line has sort of an interrogatory function. If there are several snap candidates within range, it will pop up the list as touchable icons and you tell it which you want. This includes airways around a VOR or intersections. (Hey, someone actually tested this stuff…) Also, where the GNS boxes didnt detail flightplans with intermediate and cumulative distances and time, the GTNs do. If you want to add an approach or arrival to your rubberbanded flightplan, you do that through the regular flightplan function page, accessed from the homepage. Looking forward. Garmin says the GTNs are “ADS-B friendly,” meaning they have the hooks for NextGen tie ins.

While the GNSs lacked the resolution to include paper charting functions, the GTNs do have this as standard fare. Our impression? Not that bad, but not that great, either. They still do what these devices have been doing from day one: adapting the electronic screen to the limitations of a paper approach plate.

No slam on the GTN that it does this as well as can be expected-maybe better than expected-but other than selection and interoperability improvements, the GTNs havent advanced the cause fundamentally and we doubt if they will until the industry abandons its hidebound attachment to paper.

The GTN750 can be ordered with either Garmins FliteCharts or Jeppesens Chartview. The latter will georeference aircraft position on the chart right out of the box; the former will get that capability in a future software revision. Either way, Garmins SafeTaxi feature is standard. Data cost is about $1000 a year for 28-day revision for everything in the cockpit, not just the GTNs.

We would judge these two products to be exactly what we expected. They represent a substantial, incremental improvement over the GNS line, but they arent revolutionary in capability. They are, after all, selling into a replacement retrofit market. OEM sales will likely be minimal because few new airplanes have displays that require external navcomms. If its not a single-box, fully integrated solution by now, it soon will be.

Lets qualify the above with this observation: The GTNs are revolutionary in one aspect: They will be easier to learn. You really shouldnt need to crack the POH much to either make this thing play the basic notes or to even master them at Ninja level one. Well avoid slobbering too much here, but ergonomically, theyre as good as weve seen yet.

Garmin says it will continue the GNS430/530 line for another couple of years, but were hard pressed to see why anyone wouldnt buy the GTN 650 or 750 instead. Its a slam dunk, in our view. Looking to upgrade a 430 or 530? Slam dunk again, for the GTNs.

For the bottom feeders, Garmin has just thrown the megabucket of chum into the water. Its not offering any trade-in deals, so it has no interest in bringing the old boxes back to Olathe for a one-way trip to the crusher. That means dealers will have some flex on trade-ins and a lively secondary market in used 430s and 530s will eventually erupt. But is buying one of these antiques (sorry) a reasonable thing to do, given the inevitable obsolescence? It is.

Garmin says these products have at least another 10 years of support life in them and given that there are so many out there, we suspect theyll be supportable for longer than that.

If the GTNs hit their stride as quickly as the GNS430 did, we expect to see a lot of old Cherokees sporting a pair of 430s bought on the cheap. And thats not a bad thing.