Garmin virtual panel
The Garmin "Virtual 6-pack' really DOES work, I've practised flying VOR and GPS approaches using it ALONE; it is hard work and I wouldn't want to try recovery from unusual attitudes with it, but, IT DOES WORK.
Those of you not familiar with the capabilities of modern, general aviation, portable GPS units might wish to read the following excerpt from "Aviation Consumer" magazine.
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Garmin 196
We reviewed Garmin’s GPSmap 196 in the September 2002 issue of Aviation Consumer, reporting briefly on the panel page feature. This page is easily accessible by toggling through the moving map page or numerical page with the page key. After dispensing with the disclaimer, the full screen is occupied by the five basic flight instruments described above. In addition, there are numerical repeaters for speed and altitude and values for ETE and distance to active waypoint. That means that on a single page, the 196 provides all the data necessary to remain upright and navigate to an airport or waypoint.
The 196’s position-in-space is derived entirely from three-dimensional GPS, including WAAS, which it’s equipped to receive. Altitudes are GPS altitudes which are heights above the GPS mathematical spheroid, not MSL nor precisely AGL altitudes. The 196’s displayed altitude usually jives with MSL altitude within a few hundred feet but descending on this data alone without other information could be fatal. Unless you’re having a terrible day, a partial-panel emergency will leave you without gyros but with working airspeed, altimeter and VSI instruments.
Speaking of airspeed, the 196’s is GPS-derived groundspeed, not indicated airspeed. The obvious shortcoming here is that in a tailwind, the 196’s speed will be higher than indicated and it will be lower than indicated in a headwind. For heading, the 196 uses GPS magnetic groundtrack, not true or magnetic heading.
Although it has no pitch indication other than trends in speed and vertical speed, the 196 does have a simulated turn coordinator, from which bank angle can be surmised, since the aircraft can’t turn unless it’s banked. The turn coordinator has no slip/skid ball; in a wings-level slip, it behaves exactly like a real turn coordinator, showing wings level. It does not, however, respond to initial yaw, as a turn coordinator does.
Garmin has clearly applied sophisticated software and rapid updating to get this display to work right and it does work right. You’d expect some jerkiness in the indications and although there’s a bit of that, the needle indications are surprisingly fluid and well damped. Start a bank to the left and the HSI dutifully begins winding around and the turn coordinator airplane banks left. Rolling out produces crisp enough response to hit headings—ground tracks—within 10 degrees. The acid test of these things is to fly them, either in the clouds or with outside references blocked. We did the latter by constructing a cardboard hood that restricted the pilot’s view to nothing but the 196 panel page, repeating a test Garmin showed us last summer. We wanted to see if a pilot could remain upright and find an airport and land, using only the 196.
He can and did. Our test pilot easily flew assigned headings, climbed and descended to specified altitudes and held straight and level. Because of slight display lag, the ride isn’t glass smooth. We noted a slight continuous wing rocking—a 5-degree bank either side of wings level. But headings and altitudes were easily maintained. The 196 has GPS approaches in its databases but even without using these, we were easily able to navigate to the runway centerline at Sky Acres, New York, descend and land in what we set as a 500-foot overcast and 1/2 -mile visibility. We repeated this exercise to another nearby airport, Stormville, New York, with the same results.
Pushing our luck further, we tried recovering from unusual attitudes in various pitch and bank-angle combinations. Our subject pilot—who had never laid eyes on a 196 before this experiment—recovered effectively if somewhat uncertainly. Recoveries take longer than they do with conventional instruments and there appears to be a tendency to overbank past wings level during the recovery, again due to display lag. But even with the overbanking, all of the recoveries eventually damped out to wings-level. In a real-world partial-panel event, the Garmin could keep you alive, in our view, provided it doesn’t lose power or satellite lock. If you want to navigate to an airport or fly an approach, you’ll need to be eyes-closed proficient with the navigator. The workload of flying and navigating while also puzzling out the receiver’s higher functions is simply too great. A better plan would be to find an exit to VFR weather.