Mercury Computer Systems VistaNav

If you're like me---a pilot who mainly flies airplanes with "steam gauge" instruments that look increasingly out of date---you probably salivate over the glass flight decks that are common in new airplanes. Even the latest (smallest) singles from Cessna and Piper have them. And while it's possible to retrofit similar hardware in older airplanes, for most of us, the cost (in the high tens of thousands of dollars) is prohibitive.

But now, there's a device that claims to offer full glass-panel functionality (and more) in a portable package that can be installed in any airplane with a 12- or 28-volt electrical system.

The list of features offered by VistaNav (from Mercury Computer Systems) is truly amazing---a complete system that provides Synthetic Vision (including electronic attitude indication), GPS/WAAS moving map navigation, satellite-based weather, terrain awareness, digital approach plates and even traffic avoidance (when used with Zaon Flight Systems' XRX). Add this up and it amounts to most of the functionality of a state-of-the art glass flight deck.

Physically, VistaNav consists of three major components:

(1) A combined inertial navigation unit (INU) and GPS/WAAS receiver that measures 7.8x5x2.3 inches and weighs less than a pound.

(2) An XM Satellite Radio receiver that measures 5.5 inches square by 1.5 inches deep and weighs less than a pound.

(3) A Motion Computing LS800 Tablet PC that measures 9x6.7x0.9 inches and weighs a little over two pounds. All three units require electrical power. VistaNav supplies a 12-volt power supply that operates the tablet PC, INU/GPS and XM Radio receiver from a typical 12-volt power receptacle. Mercury has wisely chosen to exploit a low-power, radio-based Bluetooth wireless connection so that no data cables are required between the INU/GPS, XM receiver and the tablet PC.

The key to VistaNav's usefulness is its software, which turns the display on the LS800 into the combination primary flight display (PFD) and multi-function display (MFD) that you see on modern glass flight decks. The default display gives the upper half to the PFD, and the lower half to the MFD, but you can switch to a full-screen view for either of those functions if so desired. The MFD is a typical EFIS moving map presentation, showing navaids and terrain---but the upper display goes well beyond what's provided by most glass flight decks. It not only provides PFD symbols, including tape-style altitude and heading along with a full-width attitude indicator, but also overlays 3-D simulated terrain, runways and waypoints.

The software was clearly designed by people with real-world flying experience. It makes good use of the buttons on the LS800 Tablet PC, so that you won't have to reach for a stylus or deal with menu-based selections in the air. A clever "radar vectors" feature displays "Highway-in-the-Sky" (HITS) boxes along your current heading and altitude---not a substitute for an autopilot, but it makes precise hand flying significantly easier. The same kind of display is available when an instrument approach is selected: Navigate the boxes and you'll eventually find yourself looking at a runway diagram.

The optional Terrain Awareness function color-codes the terrain to provide a visual indication of clearance: green, yellow and red tints indicate terrain well below, slightly below, and at or above your attitude, respectively. XM Satellite-based weather can be overlaid on the lower MFD portion of the display and may be configured to show surface conditions, including NEXRAD returns, fronts, lightning strikes and TFRs; winds aloft (at selectable altitudes) and freezing levels. You can also request text weather in METAR/TAF format for locations "sorted by distance to your current location." (This is according to the 76-page VistaNav user's guide, which is well illustrated, but lacks an index).

I see two problems with VistaNav. The first is common to all carry-on navigation devices: They can't be certified for IFR use, so even with all this functionality, you can't file or fly for GPS-based instrument flight (unless your airplane has a certified GPS in the panel). Indeed, Mercury goes beyond this, stating in the user's guide: "!VistaNav is not to be used for primary navigation." In other words, it's a backup device and shouldn't be treated as a substitute for conventional navaids. That said, I'd have no compunction at all about using VistaNav in an emergency, and because both the INU/GPS and tablet PC have built-in batteries, it will continue to work even if you have a complete electrical and vacuum system failure.

The other problem with VistaNav is wiring. While Mercury's use of Bluetooth wireless radio for the INU/GPS, XM receiver and display keeps the inevitable rat's nest to a minimum, VistaNav still involves three separate devices, each with a power cable (though a custom power supply allows this with only one plug into aircraft power), and at least one antenna (Mercury informs us that it's now selling a Duo Antenna that works for both GPS and XM weather). It's a bit much for a rental pilot or partner to set up before and completely remove after each flight. On the other hand, if you're a sole owner (or if a partnership wants to buy the system and keep it permanently in an airplane), then I don't see this as a serious problem.

On the plus side, VistaNav's display device is the fully functional Motion Computing LS800 Tablet PC with a 1.2 GHz Intel Pentium M processor, 512 MB of RAM, a 30 GB hard drive and an 8.4-inch "view anywhere" LCD that's bright enough to use with sunglasses. Unlike most other tablet PCs, the LS800 is small enough for yoke or windshield mounting, which Mercury highly recommends. A special fan-cooled mount is available with adapters for both yoke or suction-cup mounting. This is a powerful enough computer to use for many other purposes when you're not flying the airplane.

The complete system as tested (including INU/GPS, XM Radio, LS800 Tablet PC and a power supply) sells for $4,949 and includes six months of free aeronautical database updates. One year of additional updates costs $199. For the optional weather, you'll also need an XM Satellite Radio subscription, which runs $29.99 or $49.99 per month depending on the service level. If you already have a tablet PC for use as the display, lower-cost options are available beginning at $2,499 for the INU/GPS and VistaNav software. Mercury sells VistaNav hardware and software with a one-year limited warranty.

For more information, call Mercury Computer Systems at (866) 627-1671 or browse www.vistanav.com.