ADS-B: Questions to ask

More owners are asking these questions today, with the FAA’s equipage mandate approaching. Automatic Dependent Surveillance-Broadcast uses satellites instead of ground-based radar to determine aircraft location, and is a key technology behind the FAA’s Next Generation Air Traffic Control System. The FAA has mandated ADS-B Out beginning January 1, 2020, for flight in airspace where a transponder is required today.

Todd Adams, president of Lancaster Avionics—an avionics shop at Pennsylvania’s Lancaster Airport—uses a list of 10 questions to help his customers navigate the sea of ADS-B hardware choices. He shared his process during an AOPA webinar on ADS-B equipage this summer, and it was so well received that a portion of the presentation is being summarized here.

These questions can frame any aircraft owner’s ADS-B conversation with any avionics shop, although the more brands a shop represents and is familiar with, the more comprehensive the conversation can be—not every shop is a dealer for every ADS-B hardware manufacturer. (Adams’ shop is a dealer for all certified ADS-B Out hardware currently on the market, which gives him a broader perspective on the topic.)

“Discussing your panel doesn’t cost you anything,” beyond some time and maybe visiting a shop, Adams said. And what’s already in your panel can start the conversation.

Do you have a WAAS GPS? “If you already have a WAAS GPS that can be used as part of an ADS-B solution, that tells me right there that the ADS-B solution can be less expensive because you won’t have to buy one with a WAAS receiver.” The position source must meet the ADS-B rule’s requirements; most panel-mount wide area augmentation system-compatible GPS receivers do.

If not, do you have a non-WAAS GPS that can be upgraded to WAAS? From a cost standpoint, Adams said, buying ADS-B hardware with an integral WAAS GPS will be less expensive than upgrading the GPS navigator to WAAS. In this case the primary reason to update a navigator would be the ability to fly the new generation of GPS approaches, LPV and LNAV/VNAV, which require WAAS capability.

If not, do you ever want to have a WAAS GPS? A lot of aircraft don’t have a GPS, and some panels still sport obsolete lorans. “That’s where I’d start to pry a little bit, and get the owner to think about where he might be in five or 10 years down the line. Your decision today could have an impact, and provide a kind of buyer’s remorse, if you upgrade your navigation at a later date,” he said.

“Your decision today could have an impact, and provide a kind of buyer’s remorse, if you upgrade your navigation at a later date.”If you equip with ADS-B now, and upgrade your navigational capabilities later, the hardware you choose independently might not provide the level of integration you would want with a future upgrade. That’s because no ADS-B hardware is compatible with every cockpit display—especially when it comes to displaying optional ADS-B In traffic and weather information.

What kind of transponder do you have? This is a key question. “Do you have a newer digital transponder? Then maybe the better move is to go with a UAT solution. Or do you have an older transponder that at some point down the road you’re going to have to replace anyway?” A classic example is an aircraft with a Narco AT-50A, he said. “Not only is the transponder old, but Narco is no longer in business, and getting that repaired may not be economically feasible.” In such a case, a new transponder may be the prudent move—Adams said it may cost $700 or $800 more, but you won’t face the bill for a future transponder replacement.

Another consideration is foreign travel. Only 1090ES (Mode S transponder with extended squitter) is an international standard for ADS-B Out, and in every other country with an ADS-B Out mandate, 1090ES is required—so if you fly internationally, or plan to, you’ll be replacing or upgrading your transponder. (Mexico has announced an ADS-B mandate very similar to the U.S. mandate, and generally on the same timetable. Neither Canada nor the Bahamas has announced a mandate, but Cuba reportedly is testing 1090ES ADS-B.) If you already have a Mode S transponder, ask if it can be upgraded to add ADS-B Out capabilities.

By this point in the conversation, Adams said, the customer’s ADS-B platform is starting to take shape, and he or she can begin making decisions based on what’s offered by the different manufacturers.

Are you interested in ASD-B In (FIS-B weather and TIS-B traffic)? “I’m finding that most people, in one way, shape, or form, are interested in getting the ADS-B In data,” Adams said. The FAA does not require ADS-B In—but many GA pilots find that optional data to be ADS-B’s most compelling benefit. “The question then becomes, how are you going to get it?” The last five questions are closely related:

If yes, where do you want to display the data?; Do you want to display ADS-B In data on a tablet?; If yes, Android or iPad?; What app do you prefer?; If you have a preference, are you willing to change apps? These all become relevant to the discussion because no ADS-B hardware is compatible with every panel-mounted display—in the same way that not every app is compatible with each brand of hardware. “Some owners have a strong preference for a specific app. That may, in itself, define what the ADS-B solution for In is going to be.” Not all owners are willing to consider changing apps, although there are several apps on the market, Adams said.

“Once you get through that list of questions, it’s amazing how much it narrows the choices down for application for compliance, and potentially for ADS-B In, in any particular aircraft.” Adams encourages aircraft owners to discuss these questions with their shop of choice.

The entire webinar, “ADS-B Equipage and Installation,” is archived online and can be played at any time. It runs approximately two hours.

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