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Pilots obtain NavWorx AMOCs

Approvals enable UAT use with Garmin position sources

The FAA has approved several alternate methods of compliance (AMOCs) for the airworthiness directive (AD) issued June 6 that affects certain NavWorx Inc. universal access transceivers (UATs). The UATs provide Automatic Dependent Surveillance-Broadcast (ADS-B) Out and In on 978 MHz. By Jan. 11, 2018, owners of aircraft with the affected UATs must disable the unit; modify the software, which makes the unit noncompliant with the FAA’s 2020 ADS-B Out mandate; or couple the UAT to an approved GPS position source.

This NavWorx ADS600-B Universal Access Transceiver has been installed in the tail of a Cessna 152. Photo by Mike Collins.

What is an AMOC for an AD? The FAA can approve different techniques or approaches to correct an unsafe condition on an aircraft or aircraft product, in addition to remedies that are specified in the AD itself. In the case of the NavWorx AD, the agency has issued global AMOCs—also known as “AMOCs of general applicability”—that are available to any affected aircraft owner who meets the requirements of the AMOC. These AMOCs cover the Garmin GTN 650 and GTN 750 series, GNS 430W and GNS 530W series, and GNS 480 WAAS GPS position sources.

The AMOCs were obtained by three individual aircraft owners. Bob Leffler of Columbus, Ohio, requested an AMOC for the Garmin GTN 650 and GTN 750 series of GPS navigators, and has become a spokesman for the group; Ralph Capen sought an AMOC for the Garmin GNS 430W and GNS 530W series, and Phil Yoder for the Garmin GNS 480. “Ralph and I submitted our AMOCs independently before we knew each other,” Leffler said. They met through the Van’s Air Force online forum. “Phil joined in later because he’s a friend, and has the 480.

“I had never heard of an AMOC before,” Leffler continued. “It was clearly synergistic once we all knew about each other. But it wasn’t rocket science.” He and Capen simply picked up their phones and called the guy whose name was at the bottom of the AD’s final rule. Leffler said the FAA was very helpful in guiding the three owners through the AMOC process.

The fact that all three position sources already were approved as part of other manufacturers’ ADS-B solutions made the process easier, Leffler said. Each had to conduct flights to validate his position source—Leffler in his Van's Aircraft RV-10, Capen in his RV-6, and Yoder in his Beech Debonair—and obtain public ADS-B performance reports, then submit them along with the appropriate installation schematic from the NavWorx installation manual. “The how part—other than it took six or eight weeks—was pretty simple. I submitted the report and they accepted it.”

Why did they make the effort? “We didn’t have a clear idea of where this was going to end up,” Leffler explained. They thought the UAT was a good product, but with little communication from NavWorx, they were concerned they might not be able to use their units after the final rule’s Jan. 11, 2018, deadline.

Leffler said that some additional Garmin position sources in the GNS 400-500 and GTX 650-750 families were requested, but omitted from the AMOCs; he expects the FAA to add them.

Before a private operator can utilize one of the AMOCs, he or she must notify the manager of his or her local FAA fight standards district office. When Capen called his FSDO, he was asked to write a cover letter indicating that he wished to use the AMOC and include the N-number, make, and model of the aircraft, as well as a picture of the placard required by the AMOC. He was told that he will receive an approval letter allowing him to operate under the AMOC. Another FSDO might have different requirements.

NavWorx President Bill Moffitt told AOPA Aug. 15 that the company expects FAA approval of its new internal position source this week. “In addition, we have applied for a global AMOC that covers the new source, as well as the Garmin WAAS sources, and in addition the Avidyne IFD products,” Moffitt said. “We expect the global AMOC to be issued this week as well.”

FAA rebate eligibility

The FAA rebate office has said that aircraft owners who install NavWorx UATs with part number 200-0012 or 200-0013 can apply for a $500 ADS-B Out rebate if they comply with AD 2017-11-11.

“If you purchased and installed a NavWorx unit after September 18, 2016, the ADS-B Rebate Program will allow aircraft owners, who intend to comply with section (e)(1)(iv) of this AD, or use an FAA-approved Alternative Method of Compliance, to apply for a rebate,” reads an FAQ on the FAA’s ADS-B rebate website. Applicants will have to provide such documentation as purchase receipts, Form 337, and AMOC authorization letter, as appropriate, before the rebate claim can be approved. For additional questions or assistance, email the ADS-B Rebate Program.

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.
Topics: Avionics, ADS-B, Airworthiness

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