Plane & Pilot
Tuesday, November 5, 2013

ADS-B From Portable Equipment

SkyGuardTWX Vision-Pro and Adventure Pilot iFly 720

For more than a year now, we've been seeing portable devices that receive ADS-B weather, and in some cases traffic, but none provide the ADS-B out functionality required by the FAA for operation in controlled airspace beginning in the year 2020. The Vision-Pro from SkyGuardTWX fills that gap, functioning as a full-blown 978 MHz Universal Access Transceiver that sends your GPS-based position to FAA ground stations, and in turn receives traffic and weather information from those ground stations (as well as directly from other UAT-equipped airplanes).

Let's start with th­­­e good news: It works! On a local test flight near my home airport at Modesto, Calif. (KMOD), with the Vision-Pro turned on, by the time I reached pattern altitude, I was receiving traffic updates, which continued throughout my flight—and in almost every case, pointed out traffic I couldn't see with the Mark-I eyeball. And it wasn't just other ADS-B equipped airplanes—it included all transponder-equipped traffic being picked up by ATC radar in my vicinity, automatically relayed to me from ADS-B ground stations (see the sidebar for more on how the ADS-B system works).

That traffic (and weather—including local METARs and NEXRAD radar imagery) is displayed on an Adventure Pilot iFly 720 portable GPS moving map. It features a seven-inch touch screen that displays the aircraft position on geo-referenced sectional, terminal and IFR en route charts. It also displays approach charts and airport diagrams. Like the Vision-Pro, it requires external power (12 or 24 volts). Since my Skylane has only a single cigarette lighter socket, I bought a splitter at the local Radio Shack to power both devices. Adventure Pilot supplies an articulated suction-cup mount for the iFly, which works reasonably well (I wound up sticking it on the screen of a Garmin GNS-530 panel-mount GPS in order to take photos in-flight; it worked equally well stuck on the pilot's side of the windshield).

The iFly 720 has a built-in wireless internet (WiFi) adapter, which is how it connects to the Vision-Pro. That same connection can work with an iPad, and I used mine with WingX Pro7, which not only displayed GPS position, traffic and weather, but also the Vision-Pro's built-in Attitude and Heading Reference (AHARS), to support both simulated attitude indicator and synthetic vision functions. In effect, this combination provides functionality similar to what you'd get from the latest glass panel displays, but entirely on low-cost portable hardware. iFly GPS for the iPad will be released soon and will support the AHRS with a Flight Attitude Recovery System.

Now for the not-as-good news—there are a number of issues with the Vision-Pro and iFly 720 that prospective users should be aware of. For starters, both require 12- or 28-volt external power, so neither is a viable backup in case of an alternator failure. Adventure Pilot sells a $99 external battery pack for the iFly 720 that's good for approximately four hours, and can fall back on its internal GPS. I'd highly recommend that option.

A setup with both Vision-Pro and iFly installed requires a lot of wiring—power cables between each device and a 12/28- volt output, and two external antennas for the Vision-Pro. One of those is a typical GPS "puck" that goes on the glareshield, but the other one is unusual and requires some explanation. In the photo on page 63, you'll note a long blue blade connected by a cable to the VisionPro sitting on the glareshield. That's the transmitter antenna, which the brief (two-page) instructions tell you must be 18 inches from the receiver and at least eight inches away from any part of any person—it emits no less than 30 watts of power (though for only a millisecond at a time). With the VisionPro on the glareshield, in order to give its receive antenna a good view out the window (as specified in the instructions), the only place for the transmitter antenna was the copilot's window, which effectively turned my Skylane into a three-seater. This was a demo install, but with a little cord management, a clean install would have little impact.


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