ADS-B, the social network of the sky

If you or your flying friends have been following the aviation magazines or newsletters over the past few years, you have probably heard of a new technology on the horizon called Automatic Dependent Surveillance-Broadcast, or ADS-B for short. But what does that mean? What does it do? Well today, we are going to take a look.

For decades, the FAA has upgraded to better and better radar and transponder technology to track aircraft in both the VFR and IFR systems. At the same time, aircraft operators have been equipping themselves with GPS receivers for navigation and better technology for safety and efficiency of flight. While many of us used to have two VOR’s and maybe an NDB, most IFR equipped aircraft have now gone to GPS for enroute navigation. The ADS-B system can really be thought of as the evolution of your navigation system and your reporting or tracking system working together with radar and ground transmitters to provide a clearer picture of what is going on around you. With ADS-B your position, speed, heading, and aircraft information is broadcast to both ground stations and other aircraft nearby equipped with the system. Think of ADS-B like a “social network” that broadcasts where you are and where you are going shared with other pilots and controllers. But don’t be fooled, this is not a virtual crop farming or bubble game network. ADS-B could save lives by showing pilots aircraft on an intersecting flight path around mountains or approaching intersecting runways in all weather conditions. ADS-B will add a layer of safety and much greater efficiency to flying especially in congested airspace by providing pilots and controllers a better picture of what’s going on around us.

What about aircraft that are not equipped with ADS-B, how would this system see them? Traffic Information Service-Broadcast (TIS-B) which is part of the ADS-B system is the answer to that question. TIS-B increases pilot’s situational awareness by providing traffic information on all transponder-based aircraft within the vicinity of the ADS-B equipped aircraft receiving the data by rebroadcasting radar information over the ADS-B network. Therefore, even if an aircraft flying near you is not ADS-B equipped but does have a transponder it will appear as part of the TIS-B service.

TIS-B also has a little something special about it that the FAA threw in a bit late in the game to encourage early adopters. TIS-B is only available to aircraft that transmit their information over ADS-B. This means you only get traffic if you give your info to the system. ADS-B is also described as ADS-B “in” and ADS-B “out”. TIS-B is where ADS-B “in” and ADS-B “out” come into the game. The “in” describes you taking in the available ADS-B information for display on a screen (EFB, MFD, or other system). Think of it as you getting a second by second report on the area around you, but without you. The “out” part of ADS-B indicates your participation in the system. TIS-B will only work correctly for you if you provide ADS-B “out” of your aircraft. If you are equipped with only an ADS-B “in” system like some portable units currently available, you will only have TIS-B info when another aircraft very nearby has turned on the TIS-B information for its area and if you're close by you can piggy back on it for a while. Once that other aircraft flies away from you, you will no longer have any TIS-B.

In addition to the ADS-B information about traffic there is also additional information broadcast from the ground based transmitters called Flight Information Service-Broadcast or FIS-B. FIS-B will allow receiving aircraft to see weather and flight service information including AIRMETs, Convective SIGMETs, SIGMETs, METARs, SPECI, National NEXRAD, Regional NEXRAD, D-NOTAMs, FDC-NOTAMs, PIREPs, Special Use Airspace Status, Terminal Area Forecasts, Amended TAFs, Winds and Temperature Aloft when in range of a ground based transmitter. So one may ask, is this FIS-B similar to XM weather some pilots receive now? Here is the FAA’s answer to that question:
"Yes. ADS-B’s Flight Information Services-Broadcast (FIS-B) provides all of the information you would get with an XM basic subscription, and more. In fact, at no subscription cost to the user, the ADS-B FIS-B product today is comparable to the mid-to-high-level XM subscription. The FAA currently is discussing with the vendor the possibility of adding even more "no-cost" products to the FIS-B service, such as: Lightning, Turbulence NOWcast, Icing NOWcast, Cloud Tops, 1 minute AWOS – uplinked every 10 minutes."
Unlike TIS-B, the FIS-B service is transmitted all the time with or without participation in the ADS-B system. FIS-B information is not usually available on the ground or at very low altitudes due to the range of the ground-based transmitters. Once at altitude (we have found and heard that at or above 3,000 is usually a good bet) you should receive data pretty well.

So when will ADS-B be available? Well according to the FAA it should be fully available in the US 48 by the end of 2014. When will ADS-B be required? Well that depends on where you fly. For some you may never have to install and for others it may be a good idea in the next few years. January 1, 2020 is the FAA's current date to require ADS-B according to the following:
"Under the rule, ADS-B Out performance will be required to operate in:
  1. Class A, B, and C.
  2. Class E airspace within the 48 contiguous states and the District of Columbia at and above 10,000 feet MSL, excluding the airspace at and below 2,500 feet above the surface.
  3. Class E airspace at and above 3,000 feet MSL over the Gulf of Mexico from the coastline of the United States out to 12 nautical miles.
  4. Around those airports identified in 14 CFR part 91, Appendix D."
The ADS-B Out rule does not apply in the airspace defined in items 1 and 2 above for any aircraft that was not originally certificated with an electrical system or that has not subsequently been certified with such a system installed, including balloons and gliders.

So when will FlightPrep have ADS-B capable applications? Soon, sometime in the next 12 months. Since the system is still being built there are currently dead spots in coverage throughout the country but 2014 will be here before you know it so we're getting ready. Stay tuned for more information on ADS-B in a future newsletter.

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