ADS-B: Installing a UAT

ADS-B, which uses satellites instead of ground-based radar to determine aircraft location, is a key technology behind the FAA’s Next Generation Air Transportation System. The FAA has mandated ADS-B Out equipage beginning January 1, 2020, for operations in most airspace where a transponder is required today.

HARDWARE SELECTION

AOPA acknowledges the benefits of, and the need for, the transition to ADS-B. But the association also has advocated for less-expensive ADS-B Out hardware that complies with the mandate. Today several 978-MHz universal access transceivers (978UATs) are available for around $2,000. We also wanted to see whether having an airframe and powerplant mechanic install the ADS-B hardware during the aircraft’s annual inspection—when the interior is already removed—might help to reduce installation labor costs.

First up was N152UF, a Cessna 152 based in Florida. Because it doesn’t operate in the flight levels, or anywhere else that the 1090-MHz datalink is required, we selected NavWorx’s ADS600-B. The unit lists for $1,999 and includes an integral, rule-compliant WAAS GPS position source (152UF’s panel does not have a suitable GPS); the optional ADS-B In capability for traffic and subscription-free weather, with a Wi-Fi module that allows wireless display of traffic and weather on a tablet; and an approved model list (AML) supplemental type certificate (STC) that allows for its installation in many certified GA aircraft.

The rule requires a single point of entry for your squawk code—the aircraft transponder. However, ADS-B Out equipment must know your transponder code, as well as your Mode C altitude. For aircraft with newer, digital transponders—such as the Garmin GTX 327, GTX 330, or SL70, or the Sandia STX 165—the ADS600-B can receive that information digitally. Older transponders will require NavWorx’s $199 TransMonSPE, which slips over the transponder coax cable to receive its Mode A and Mode C replies. 152UF has a GTX 327, so we did not require that accessory.

Many avionics manufacturers require that their products be installed by authorized dealers. NavWorx will sell directly to an aircraft owner. Hardware availability from any manufacturer can vary, and some avionics shops have said they won’t schedule an ADS-B installation until the hardware is in hand. Last fall a few AOPA members reported waits for NavWorx UATs, so we ordered early from the NavWorx website—and our purchase arrived in a timely manner about two weeks later.

FINDING A SHOP

Bill Boege’s Propellerhead Aviation, an aircraft maintenance and flight training operation in Winter Haven, Florida, has been servicing 152UF, and he agreed to install the UAT during its annual in January. While mechanic José Roman completed the final tasks of the annual, Boege unpacked the UAT’s installation hardware on a table beside the yellow Cessna and began studying the installation manual. He also reviewed the installed Garmin GTX 327 transponder’s manual, and began the process of determining the pin configurations for the wiring harness.

Once the proper locations for the UAT’s antenna and the antenna for its integral WAAS GPS were determined—placement is very important—their installations were routine. Boege determined that a position in the tail cone, just below the emergency locator transmitter, was best for the UAT transceiver; his team fabricated a mounting bracket. Work on the wiring harness was most time-consuming, he said. Boege has a fair amount of avionics experience, as well as the precision wire strippers, pin crimpers, and other special tools needed for this kind of job.

Boege noticed in the manual that the NavWorx UAT should display traffic on the Garmin aera 560 mounted in the 152. “We should try to make this work,” said the pilot and active CFI, who understands the value of the additional situational awareness that would provide. He did.

Much of the installation time is spent on one’s stomach, reaching into the tail cone—or back, reaching up behind the panel. “You can’t do this for eight hours or 10 hours at a time—you’ve got to switch to something else, to save your back,” Boege said. “It doesn’t add hours to the job, but it adds calendar days, because you’re not working on it all day.”

While Boege found nothing in the project that can’t be figured out by a mechanic with basic electrical skills, he said it might not be a good fit for a shop without some avionics experience. NavWorx’s customer support was excellent, he added. “It’s a good practice to really verify where those wires go ahead of time, instead of hooking them up and having to undo it later. It takes a lot of time to go back and forth.”

The bill for the ADS-B install was 28 hours of labor, and $55 for parts (a circuit breaker, the bracket, and some wire). “I was pretty happy with the amount of time it took, being a first installation. After this one, the next couple will be a lot quicker,” he said. “The initial installation is really an investment, as far as a shop goes.” He could see an install time of 20 hours or less, and said area avionics shops were quoting about 25—at least some of that difference would be removal and reinstallation of the interior.

Boege suggests that a mechanic or small shop research the available units, pick one, and stick with it. “You’ll get real familiar with the installation process. It’s a clean installation—it’s not a dirty job.” Incorporated with an annual inspection, he believes both customer and shop will benefit. Boege plans to offer ADS-B installations to other customers.

CONSIDERATIONS

While it’s perfectly legal for an A&P/IA to install a UAT, as Boege noted, not every mechanic is suited for the task. The Aircraft Electronics Association, the trade organization representing avionics manufacturers and installers, is not enthusiastic about the typical A&P tackling an ADS-B installation. “ADS-B is embedded in so many technologies, it’s difficult to say what ADS-B is,” said Ric Peri, AEA’s vice president for government and industry affairs. “It’s one thing to talk about a blind box, but it’s another to alter the primary GPS navigation source in the aircraft.”

Even if an A&P has a background in avionics work, Peri said, he cannot repair or alter an instrument—including a primary flight display. And tools and test equipment are required to do the job properly, he added. “If you encourage a random A&P to do [an ADS-B installation] without proper training, you’re setting yourself up for failure.”

Peri suggests that an aircraft owner encourage his A&P to partner with an avionics shop. “There’s nothing to prevent the owner/operator from initiating that conversation.” Or coordinate the installation during your aircraft’s annual. While the interior is out, tow it to the radio shop for the installation. “We need to find creative ways to be frugal.”

TO BE CONTINUED

Next month, we’ll look at two more ADS-B hardware installations—one by another A&P, and one by an avionics shop. While I don’t want to give away all the conclusions, I don’t want to keep you hanging if your annual is almost due. So here’s some foreshadowing: Asking a qualified A&P, who is comfortable working with avionics, to install a UAT during your aircraft’s annual is an option worth exploring. Finding the right A&P may be a challenge. And if he or she isn’t comfortable with the required electrical work—move on. None of you will be happy with the result.

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