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The buzz about transponders

What early ADS-B Out adopters have to say

As of April, when the Aircraft Electronics Association held its annual convention in Dallas, it was announced that about 10,000 U.S. aircraft had equipped for ADS-B Out, the technology that will be required beginning January 1, 2020, to fly in most airspace where a transponder is required today.

P&E ADS-BIn July, we asked those of you who already have equipped to tell us about your experiences with ADS-B (“ADS-B: Going With the Flow,” July AOPA Pilot). Thanks for your many responses, which still are coming in.

Many early adopters—well, many of those responding—have achieved compliance with the ADS-B Out rule by upgrading an existing Mode S transponder, or installing a new one, that appends the ADS-B Out data to its 1090-MHz transmission with an extended squitter (1090ES) capability. (The other option for ADS-B Out compliance is a 978-MHz Universal Access Transceiver or 978UAT).

Several replaced old transponders that they believed were on their last legs—a logical consideration, because you still must maintain a working transponder after the ADS-B rule takes effect. Many wanted a straightforward solution that leveraged equipment already in their panel, and/or mentioned strong brand loyalty.

Ross Palmer of Las Cruces, New Mexico, decided early last year to remove a bunch of old avionics from his Cessna 182A and install a Garmin GNS 430W, a Garmin audio panel, and a Garmin GTX 330ES transponder.

“If I had not wanted to replace my aging transponder, I would have gone the 978UAT route via Garmin,” he said. For ADS-B In, Palmer uses ForeFlight and a Stratus receiver with an external antenna.

“I’m delighted at the extra situational awareness I get now when I fly. When on flight following, I usually see opposing traffic long before Center advises me of it,” Palmer said. “I know cost is a major concern for a lot of people—it was for me, too. I can’t imagine why everyone who flies at IFR altitudes and normally uses flight following wouldn’t want the extra traffic-awareness ‘safety net’ the system provides.”

Expanded nav capability

Larry Randall, who bases his 1974 Cessna 172 at Charlottesville-Albemarle Airport in Virginia, upgraded it last year. “My plane had an older VFR GPS and a very old transponder. I knew this would cost a fair amount but felt it was worth it.” He selected a Garmin GPS 400 navigator and a GTX 330ES transponder for its ADS-B Out capability, noting that the transponder also displays TIS-A information on the GPS 400. Randall receives ADS-B In weather through a tablet application.

“One of the reasons I went to the IFR GPS solution was to get the new [WAAS LPV] approaches. The system has evolved such that if you cannot fly GPS approaches, sometimes you are out of luck.” He said installation took only a couple of days after the radios came in, although he experienced some setup and configuration issues—a not-uncommon experience—that the shop corrected. “Overall I like the new system,” he said. “The inexperience of the shop and the need to replace some plastic parts that were damaged were really the only issues I had.”

Phased approach

Robert Vinyard keeps his sharp-looking 1964 Cessna 172E at Hutchinson County Airport in Borger, Texas. “I personally was excited about what the future of ADS-B was bringing. I hear a lot about the large amount of money this is costing our government, but I never hear how much money it’s going to save by shutting down all that old equipment and not having to spend tons of money making repairs. There has to be a tradeoff.”

He’s kept the Skyhawk up to date, with a fresh engine overhaul, a recent paint job, and a nice panel that includes a Garmin GNS 430W. He said the last piece was a Bendix/King KT 74 1090ES transponder that replaced an old Narco AT50. “I knew this was coming, and over the past 10 years I have been saving and paying cash for the upgrades. I wanted to get it done early to avoid the rush in the shops.”

Not quite plug and play

When John Epley of Marianna, Florida, purchased his Beech Bonanza N35 in 2007, the panel already sported a Garmin GTX 330 transponder. “Last year I sent it to be upgraded to Extended Squitter for a reasonable $1,200. After I got the transponder back from Garmin and reinstalled it, I learned the hard way that it wasn’t going to be a plug-and-play replacement.” A nearby avionics shop quickly made the necessary connections.

Epley hasn’t decided which way to go for ADS-B In yet. “I already have XM Satellite weather through my Garmin GDL 69 weather receiver feeding into my GNS 530W and 430W, and I also have Garmin’s TIS. Panel-mounted ADS-B In receivers are too expensive for me right now, and I’m not sure a portable receiver is right for me either.” He planned to look at available options at AirVenture in July.

A trend?

Why are so many early adopters going the 1090ES route with a new transponder, instead of a 978UAT datalink transceiver? Many of these examples were logical upgrades based on existing equipment, and not a need to fly where 1090ES is required (above 18,000 feet or in some airspace outside the United States).

In part, it may be because there are so many products from which to choose. Consider that in addition to the Garmin examples cited above, Avidyne, Bendix/King, FreeFlight Systems, Garrecht, L-3 Avionics Systems, and Trig Avionics all offer 1090-MHz Mode S Extended Squitter transponders. Two transponders, L-3’s NGT-9000 and Appareo’s Stratus ESG—the latter currently in certification testing, with availability expected in 2016—also incorporate a WAAS GPS position source, which could simplify installation for owners of airplanes not already equipped with an approved positon source.

Things could change in the coming months. At the end of June, FreeFlight Systems announced that its line of Ranger Lite systems, which had recently received FAA supplemental type certificate and approved model list certification, were shipping. The FDL-978-TXL, an ADS-B Out-only unit, is priced at $1,995 plus installation; the ADS-B In/Out FDL-978-XVRL is $3,695—and the units include a built-in WAAS GPS receiver, as well as ADS-B and GPS antennas, an install kit, control head, and WiFi module if needed.

And NavWorx is offering its ADS600-B, a remotely mounted 978UAT with an integral WAAS GPS receiver and ADS-B In/Out capabilities, for $1,799. Watch these pages for more information on both of these products soon.

Email [email protected]

Web: See AOPA’s new online ADS-B resources and ADS-B selection tool. 1090ES replacement transponders also are listed.

Mike Collins

Mike Collins

Technical Editor
Mike Collins, AOPA technical editor and director of business development, died at age 59 on February 25, 2021. He was an integral part of the AOPA Media team for nearly 30 years, and held many key editorial roles at AOPA Pilot, Flight Training, and AOPA Online. He was a gifted writer, editor, photographer, audio storyteller, and videographer, and was an instrument-rated pilot and drone pilot.

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