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 thÂÂÂe 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.

I discussed this with Adventure Pilot's Shane Woodson and SkyGuardTWX's Don Houtz, who both use these devices in their airplanes. SkyGuard has a remote receiver antenna option that allows you to move the device off the glareshield, and if you have (or can rig) 12/28-volt power in the baggage compartment, putting the Vision-Pro there will let you use all your passenger seats. Houtz told me he plans to offer a remote mounting kit for those who want to permanently install the Vision-Pro, which will support external antennas.

There are no power switches, so it's best to physically disconnect both the Vision-Pro and iFly before engine start or shutdown (I just pulled the splitter out of the cigarette lighter). SkyGuardTWX doesn't provide any mounting hardware for the Vision-Pro. I improvised with Duct tape. The Vision Pro is configured using software (either a sub menu on the iFly or SkyGuardTWX's iPad/iPhone app). I was surprised to find the transmitter is on by default, even before you've entered your N-number and the associated ICAO code. Houtz agreed that ought to be changed. The software also would allow a user to change the N-number/ICAO code in-flight, which could present a
security issue.

If ATC assigns you a squawk code, you'll need to set it twice---both on your Mode-C transponder and using software to configure the Vision-Pro. Exactly that sort of thing created problems in early FAA "Project Capstone" tests of ADS-B in Alaska, and led to a recommendation (though not currently a requirement) for ADS-B out systems to offer a single control to set a squawk for both ADS-B and Mode-C.

The final issue for this setup is regulatory: While SkyGuardTWX has received FCC approval for the Vision-Pro (otherwise it would be illegal to turn the transmitter on), it has not as yet received FAA certification, though Houtz told me he's working toward that goal. If the FAA doesn't certify it, you'd have to buy something else to meet the 2020 ADS-B out mandate.

In the meantime, if you want to have full ADS-B in/out functionality, the Vision-Pro looks like the least expensive way to achieve it, and if you don't already have an iPad (or want another screen for dedicated traffic display), the iFly 720 is a good option for $699.

Adventure Pilot sells both the Vision-Pro and iFly 720 in a bundle for $1,994, and the Vision-Pro by itself for $1,399 if you already have an iFly. An additional $400 will get you the Vision-Pro with an integrated AHRS. Visit www.iFlyGPS.com and www.skyguardtwx.com.


ADS-B Update
Three years ago, the FAA mandated that as of January 1, 2020, aircraft operating in U.S. class A, B or C airspace and in class E airspace above 10,000 MSL (and above 2,500 AGL) must be equipped with one of two ADS-B out data links: an enhanced form of the Mode-S transponder already used by most airliners, especially on international flights; or an alternative technology called Universal Asynchronous Transceiver (UAT) that was developed for the FAA's Capstone program. The two radio links operate in different frequency bands. One is an enhanced version of the 1090 MHz Mode-S link called Extended Squitter (ES). It's the easiest to understand: replace your existing transponder with a Mode-S transponder that supports 1090ES operation, and you're equipped to meet the FAA mandate. Unfortunately, the 1090 MHz frequency band is congested---all existing transponders, whether Mode 3/A, C or S, respond to interrogation at 1030 MHz with a reply on 1090 MHz. As an alternative, the FAA supports ADS-B on the less congested 978 MHz frequency band, which requires a completely new piece of equipment called a Universal Asynchronous Transceiver (UAT). A UAT doesn't replace your transponder it's a separate piece of equipment installed in addition to your transponder, which is still required because the FAA plans to keep about half of today's surveillance radar sites as a backup and to verify integrity of the ADS-B system. The one-way link from aircraft to ATC described so far is ADS-B out, which is being mandated by the FAA. ADS-B in is an optional system that transmits information from the ground to aircraft for display in the cockpit. This includes traffic information: With a UAT and display, you can "see" other 978 MHz traffic, but not traffic that's sending on 1090 MHz. To deal with that, ADS-B ground stations include a feature called ADS-Rebroadcast (ADS-R). Signals from any 1090-ES-equipped traffic near an aircraft that listens on a UAT are copied and transmitted on 978 MHz and vice-versa. Another feature called Traffic Information Service-Broadcast (TIS-B) does the same thing for transponder-equipped aircraft not equipped with ADS-B, if you're flying in a radar service volume. The effect is that with either a 1090ES or 978 MHz ADS-B receiver and display, you'll have a complete picture of all traffic near your position, provided you're in line of sight of a ground station. Airplanes with a UAT can also receive Flight Information Services--Broadcast (FIS-B), including NEXRAD radar mosaic, current weather conditions, terminal forecasts, significant weather alerts, winds and temperatures aloft and pilot reports, along with temporary flight restrictions and other notices to airmen. Unlike satellite-based weather services that require a monthly subscription, once you install the receiver and display, FIS-B is free. An issue to consider: coverage. In the continental U.S., ADS-B coverage is good along the Atlantic and Pacific coasts, throughout the South and in the Great Lakes region---but much more limited in the Central and Mountain regions---Wyoming, Montana and Colorado have little or no coverage, because very few ADS-B ground stations haven't been activated yet in those states. None have been installed in the Hawaiian islands or Puerto Rico at this writing.

ADS-B Update

Three years ago, the FAA mandated that as of January 1, 2020, aircraft operating in U.S. class A, B or C airspace and in class E airspace above 10,000 MSL (and above 2,500 AGL) must be equipped with one of two ADS-B out data links: an enhanced form of the Mode-S transponder already used by most airliners, especially on international flights; or an alternative technology called Universal Asynchronous Transceiver (UAT) that was developed for the FAA's Capstone program.

The two radio links operate in different frequency bands. One is an enhanced version of the 1090 MHz Mode-S link called Extended Squitter (ES). It's the easiest to understand: replace your existing transponder with a Mode-S transponder that supports 1090ES operation, and you're equipped to meet the FAA mandate.

Unfortunately, the 1090 MHz frequency band is congested---all existing transponders, whether Mode 3/A, C or S, respond to interrogation at 1030 MHz with a reply on 1090 MHz. As an alternative, the FAA supports ADS-B on the less congested 978 MHz frequency band, which requires a completely new piece of equipment called a Universal Asynchronous Transceiver (UAT). A UAT doesn't replace your transponder it's a separate piece of equipment installed
in addition to your transponder, which is still required because the FAA plans to keep about half of today's surveillance radar sites as a backup and to verify integrity of the ADS-B system.

The one-way link from aircraft to ATC described so far is ADS-B out, which is being mandated by the FAA. ADS-B in is an optional system that transmits information from the ground to aircraft for display in the cockpit. This includes traffic information: With a UAT and display, you can "see" other 978 MHz traffic, but not traffic that's sending on 1090 MHz. To deal with that, ADS-B ground
stations include a feature called ADS-Rebroadcast (ADS-R). Signals from any 1090-ES-equipped traffic near an aircraft that listens on a UAT are copied and transmitted on 978 MHz and vice-versa. Another feature called Traffic Information Service-Broadcast (TIS-B) does the same thing for transponder-equipped aircraft not equipped with ADS-B, if you're flying in a radar service volume.
The effect is that with either a 1090ES or 978 MHz ADS-B receiver and display, you'll have a complete picture of all traffic near your position, provided you're in line of sight of a ground station.

Airplanes with a UAT can also receive Flight Information Services--Broadcast (FIS-B), including NEXRAD radar mosaic, current weather conditions, terminal forecasts, significant weather alerts, winds and temperatures aloft and pilot reports, along with temporary flight restrictions and other notices to airmen. Unlike satellite-based weather services that require a monthly subscription, once you install the receiver and display, FIS-B is free.

An issue to consider: coverage. In the continental U.S., ADS-B coverage is good along the Atlantic and Pacific coasts, throughout the South and in the Great Lakes region---but much more limited in the Central and Mountain regions---Wyoming, Montana and Colorado have little or no coverage, because very few ADS-B ground stations haven't been activated yet in those states. None have been installed in the Hawaiian islands or Puerto Rico at this writing.

John D. RuleyWriter

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