ADS-B is coming, like it or not

 - March 27, 2011, 6:15 AM

Mention ADS-B in a group of pilots and the likely result is puzzled looks and a change of subject. To many pilots, ADS-B is something that is coming someday, and they’ll learn about it when forced to. There is an easier way, however, and it’s not terribly expensive, in relative terms. Instead of going for a full-blown ADS-B in or out or both installation, which can cost thousands of dollars, why not run ADS-B on your Apple iPad?

Radenna, an 18-month-old Revere, Mass.-based development enterprise run by Alexey Zaparovanny, founder and chief technology officer, and CEO Vladimir Geisberg, offers a receiver that displays ADS-B in traffic and weather on an iPad moving-map app. Called SkyRadar Pro, the app is aptly named, because ground-based radar is what ADS-B is eventually supposed to replace.

Theoretically, if all aircraft were equipped with ADS-B in and out systems, pilots and controllers would all be able to see all traffic pretty much anywhere (the distance will likely be limited to 150 miles). This would give controllers a much better view of where traffic is in real time and allow more favorable routing, timed arrivals in busy terminal areas and reductions in spacing between aircraft.

More advanced capabilities could include the ability of aircraft that can “see” each other to allow for, say, routing or altitude changes that are currently precluded because exact locations of aircraft are not readily available to controllers, especially over oceans and sparsely populated areas. (Of course, this depends on the ability of these aircraft to transmit and receive to and from ADS-B ground stations, and over remote areas this might require satcom capability.)

But none of that is going to happen until ADS-B equipment becomes standard in most cockpits. And until pilots understand what ADS-B can do and how it works, resistance, though futile, will likely be typical.

SkyRadar Pro Test

During a recent flight from Santa Monica Airport, I flew in the back seat of a training flight in a Cirrus SR22 with Joe Justice, owner of Justice Aviation, and his student to test Radenna’s ADS-B receiver and SkyRadar Pro. The receiver is housed in a small box that could easily sit on the glareshield. An external Waas GPS receiver plugs into the box, as does a power cable that plugs into a cigarette lighter-type power supply. The receiver communicates wirelessly (via Wi-Fi) with the iPad.

ADS-B requires ground stations that transmit weather and traffic information to airborne receivers. One unique aspect of ADS-B is that weather information (flight information services-broadcast or FIS-B) is transmitted automatically on the two system frequencies, universal access transceiver (UAT 978 MHz) and 1090 extended squitter (1090 MHz). But traffic information (traffic information services-broadcast or TIS-B), also using the two frequencies, is transmitted only when an ADS-B out signal from an aircraft equipped with an ADS-B out transmitter wakes up the ground station.

The Radenna ADS-B receiver currently is not equipped with a transmit function. TIS-B will display both aircraft reporting their position via ADS-B out as well as aircraft picked up by FAA radar. Many parts of the U.S. are currently covered by ADS-B ground stations, but full continental U.S. coverage is not expected to be in place until 2013.

Unfortunately, no aircraft in the Los Angeles area woke up the ground station, so I was unable to view traffic information on the SkyRadar iPad app. When TIS-B is working, airports with ground radar will display ground traffic on the airport chart.

The weather data worked well, although I was unable to see any Nexrad images. This was because the normally good southern California weather yields few opportunities to see storms that would show up on Nexrad. The SkyRadar app is currently programmed to display local Nexrad images, not those over the continental U.S. Future versions will provide Conus coverage, according to Zaparovanny. “It is not a receiver limitation.”

The SkyRadar app did a great job of displaying free FIS-B information, including Metars, Tafs, Notams, winds-aloft forecasts and graphical TFRs. The ability to display TFRs as soon as they are published makes the SkyRadar app with ADS-B receiver a valuable tool. Oddly, Metars are translated into plain English, while TAFs remain in code. The primary benefit of using an ADS-B receiver like Radenna’s is that the data is free, saving the monthly fees for services like XM’s or WSI’s products (both of which offer more information than ADS-B). Essentially, with monthly fees, pilots pay whether or not they are flying. With SkyRadar/ADS-B, there is no ongoing fee.

The SkyRadar app (also available for the iPhone) includes a 90-meter resolution terrain display and the ability to plan flights but not file flight plans. On the ground with a good Wi-Fi or Internet connection, the SkyRadar app can pull up NOAA weather. The app also allows downloading of IFR low and high en route charts as well as approach plates. A separate subscription to Seattle Avionics is required for the charts. If you already have a Seattle Avionics subscription for another iPad app such as WingX, Seattle Avionics lets you log in and use the subscription for any iPad app, including SkyRadar. The charts and approach plates are geo-referenced, so you see your aircraft’s own-ship position on the charts if you have the GPS-equipped iPad 3G or an external GPS. One neat feature when using approach plates is that if your aircraft is outside the boundaries of the plate, an orange arrow points to your ship’s position. As you fly closer to the airport on the plate, your aircraft symbol will fly onto the plate from the direction that the arrow is pointing.

The en route charts can be zoomed with the two-finger Apple pinch/unpinch gesture or there are zoom buttons in the app. Without the en route charts overlay turned on, the app shows a basic outline of the terrain and features, but not in the detail presented by a VFR chart. The VFR display is simple and uncluttered. Tapping onto any element shown on any of the charts or VFR display pulls up information about it, such as airport info and weather, airspace boundaries and so on. The overlay menu allows for customizing the view and decluttering as desired. SkyRadar has its own lock and brightness buttons so you don’t have to use iPad controls for these.

There is currently no cheaper way to try out ADS-B in services than Radenna’s SkyRadar app ($26.99, includes airport data updated every 56 days and airspace updates every 28 days) and ADS-B receiver ($1,199.95). Seattle Avionics charts are another $99 per year. It would be useful if Radenna could add a transmitter to wake up the ADS-B ground stations, but that would require meeting some certification standards and would raise the price. “You cannot broadcast if it’s not certified,” said Geisberg. “That is the Achilles heel of this whole concept at this juncture.” o