Pity the poor instrument pilot on a low approach. After slogging through rain, bumps and too many clouds, he or she slides toward a runway from the final approach fix, straining to see what's ahead. Needed is something within the runway environment: approach lights, centerline lighting, the runway edge lights. Using precious milliseconds of attention from the instruments to anxiously peer outside in search of something -- anything -- familiar means those same milliseconds aren't being used to fly the airplane. On too many occasions, the result has been an ugly, smoking ball of aluminum.

Recognizing that pilots needed some help during such a critical flight phase, NASA years ago developed a concept called "highway in the sky" (HITS) as part of its small aircraft transportation system, or SATS. It's one of the few things NASA has done in recent years that acknowledges the first "a" in its name stands for "aeronautics." It's also something that's failed to live up to its promise, at least at the low end of GA. Until recently.

Enter synthetic vision systems, or SVS. First developed by NASA and the U.S. Air Force in the late 1970s and 1980s as a way to enhance situational awareness, it uses terrain, obstacle, geo-political, hydrological and other databases -- along with GPS-derived position-finding -- to project images of what's outside an aircraft without actually seeing them. In high-end applications, the images are projected on a heads-up display (HUD). Until HUDs make their way down the ladder to personal GA, though, synthetic vision is being displayed on glass panels. This is, of course, different from an infrared-based technology, known as enhanced vision systems (EVS), developed in recent years most notably by Kollsman and commonly available on newer Gulfstream bizjets.

Synthetic vision for GA has been around for a while, first available in experimental avionics systems from Blue Mountain, Chelton and Vista Nav, to name but three. Now, the technology has gone original equipment in light GA, having been embraced -- and installed -- in new, Garmin G1000-equipped offerings from Cirrus Designs. Not to be outdone -- or displaced -- Avidyne this week is upping the ante and introducing SVS and EVS capabilities on the latest implementation of its Entegra glass panels.

Avidyne says its SVS offers improvements over other systems by depicting 3D terrain all the way to the horizon, based on the aircraft's agl altitude, as well as the HITS boxes through which the pilot or his autopilot should be flying. Meanwhile, the EVS Avidyne is demonstrating uses an infrared camera to "see" through most obscuring phenomena. The company says pricing and availability of the required Entegra upgrades will be announced at a future date.

It's all good, of course, and it's long past time for this technology to trickle down to personal GA. I have a warm spot in my heart for Avidyne, if for no other reason than someone needs to provide healthy competition in the avionics market to Garmin's 800-pound gorilla. Now, if someone can come up with a reasonable -- in time and money -- glass-panel retrofit for older aircraft like my '66 Debonair, I'm all ears (especially if it includes financing).

Oh, and we need a HUD, guys.