Pilot's Guide to Avionics 2012-2013 - 74

WAAS GPS

Continued from page 72

No doubt, thousands of these devices are still flying – several wholly obsolete Loran C navigators and lots of their successor GPS navigators, many TSO’d for IFR non-precision approaches. Increasingly, these aircraft owners voice some frustration at the lack of new WAAS navigators that are not part of some all-in-one nav/comm/GPS package and sized to fit into the slots of their existing area navigators. “There must be thousands, even tens of thousands that would be replaced with a WAAS version if someone offered it,” one pilot recently observed. But, if there’s a 2-inch version in the works, it’s not apparent, though some avionics-business insiders conceded the market potential while noting the ongoing development of other viable WAAS options. For the moment, it appears that the 2-inch option is dormant, and there’s more happening in what some insiders peg as the successor size to the 2-inch-height box of 15 years ago. But, there are growing options for aircraft owners interested in adding only WAAS GPS without the extra expense and added installation from the growing numbers of all-in-one options.

with one of the earlier multifunction displays complementary to any traffic or weather sensors. Aside from that early generation IFR GPS, many owners are happy with their stacks. “Why,” asked one nonplussed pilot recently, “doesn’t anyone make a WAAS-certified box that will fit that space where my (old GPS) fits?” He and other pilots are often past early adapters who quickly moved on TSO C129a GPS navigators when they arrived, opting for Class A1 units to gain the utility of an IFR-approved area navigator also approved to fly terminal procedures and non-precision approaches. Now, many pilots are eager for WAAS, but not necessarily at the cost of replacing what still works well – among them the existing, late 1990s MFD, two alsoperfectly functioning VHF nav/comm, both with glideslope and working connections to his autopilot system …as is the IFR GPS. What is ideal for the pilot? A so-far non-existent WAAS GPS to “slide in” as a replacement for the TSO C129a he/she wants to slide out – and leaving everything else in place. This is not a likely option – at least, not in the short term.

Size Does Matter…
So, where are those 2-inch WAAS-approved navigators, or when are they coming? For now, the answer seems to be nowhere and not soon. Avionics company staff explained that the smaller screen space available isn’t very compatible where avionics designers are going. According to Avidyne’s Tom Harper, the 2-inch-high space leaves too little space for a display screen that can serve up a sophisticated touch-control menudriven interface while leaving room for any required buttons or knobs. That standard, Harper said, is now two generations passed, displaced 13 years ago by a return of the larger faceplate in the form of Garmin’s landmark GNS430. And, other boxes heralded a move back to taller components with the launch of Honeywell’s Bendix/ King 3-inch tall KMD-250 multifunction display a decade ago.
Continued on page 76…

Change – There’s Always A Price
With a general aviation fleet aging faster than it’s growing, it’s no secret that today’s owners and pilots fly a very old fleet with lower residual values on the open market than in years. The two dominant-size packages in their panels come down to the 6.26-inch-wide box measuring either 2 inches or 2.5 inches tall. These slots are filled with thousands of VHF nav and comm, nav/comm, transponder and audio-panel gear. While the 2.5-inch-high standard carried nav/comm and automatic direction finders through the 1950s and 1960s avionics designs, the evolution moved from the first solid-state Bendix/King KX-175 and KX-170B nav/ comm to the slimmer 2-inch digital-display integrated electronics descendants – the KX-155 and KX-165 nav/comm, which both fit the emerging form factor: 6.25 inches wide by only 2 inches tall. Many pilots opted to pair one of the emerging visual flight rules and IFR GPS or GPS/comm navigators

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Pilot's Guide to Avionics 2012-2013

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