ADS-B provides the type of accurate, up-to-the-minute surveillance that business and general aviation operators crave, but an innate aspect of the technology presents security and privacy concerns that still do not have a proper resolution. The continued proliferation of privately owned ADS-B ground-based receivers allows virtually anyone with roughly $100 worth of surveillance equipment to track the flights of any 1090 MHz ADS-B-equipped aircraft.

There are a variety of perspectives on this issue, including those of scheduled commercial airlines who actually benefit from the wide-open tracking of their aircraft that ADS-B enables. Others, including business and general aviation pilots and maintenance technicians who work on business aircraft ranging from turboprops to corporate jets, see no issues with privacy of their aircraft. The ease of tracking ADS-B-equipped aircraft also presents a challenge for military aircraft that must be equipped with upgraded transponders to fly in civilian airspace.

This is still an issue for which the National Business Aviation Association (NBAA) is actively searching for a technological resolution. The PiAware GroundStation kit, which includes a Model 3 computer, SD Card, a USB receiver and indoor antenna, is available for less than $100 and allows users to build their own mini ADS-B ground station to track ADS-B-equipped flights for 100 to 300 miles. That’s the type of tracking some operators would like to avoid.

Most pilots see the benefits in ADS-B, including its better-than-radar surveillance capability and the reduced expense required to maintain ADS-B ground stations versus ground-based radar. However, certain aspects of ADS-B have reduced privacy they previously enjoyed from being able to block their aircraft from being tracked by individuals who are not air traffic controllers with technology such as PiAware.

Two business aviation legends, John and Martha King, who provide course training videos and software for flight schools and air transport companies throughout the world, have a unique perspective on the issue.

“A very small percentage of people in the world care who John and Martha King are, but they happen to be around airports,” John King, co-founder of King Schools told Avionics International. “One of our preferences would be not to be announcing where we are all the time because people can show up and it’s a risk factor.”

The Kings are well-known in general aviation circles. In 1994, they became the first flying husband and wife to both hold every category and class of FAA ratings on their pilot and instructor certificates. They fly a Falcon 10 to attend meetings, aviation conventions and occasionally visit the flight schools they support.

A $60,000 investment provided an upgrade and flight-testing of new ADS-B transponders and wide area augmentation system (WAAS) GPS on their Falcon 10.

“ADS-B allows us to be tracked — it is broadcasted to everyone,” said Martha King. “Before we equipped with ADS-B earlier this year, we were part of the [Blocked Aircraft Registration Request (BARR)]. We requested to keep that status with ADS-B; however, it does not work. We need a technological solution that will allow ATC to see you, but blocks you from the inexpensive ADS-B ground receiver equipment.”

The issue was first raised by NBAA during several meetings with FAA officials between 2013 and 2014, at which time the joint-industry ADS-B Implementation Working Group (JAIWG) was briefed on tracking ADS-B-equipped aircraft using low-cost ground stations and bypassing the protections established in the BARR program for display of aircraft on situational displays.

Aircraft equipped with Mode S transponders broadcast a 24-bit address code assigned to each aircraft registration number, also known as an aircraft’s International Civil Aviation Org. (ICAO) address. This means the privacy concerns business aviation operators have go beyond ADS-B.

Mode S transponder technology also negates some of the FAA’s Aircraft Situation Display to Industry (ASDI) program’s privacy benefits. Each aircraft’s assigned ICAO code is based on its registration and a public algorithm that makes the position of the aircraft publicly available.

“What we’re asking for is that the list of aircraft IDs not be made public and not have our name attached to it,” said King.

There are technological solutions that exist, although they’re much easier to obtain at lower altitudes, below the 18,000 feet 1090 MHz world of corporate jetliners like the Kings’ Falcon 10. The U.S. is one of two countries in the world that feature a 978 MHz frequency for ADS-B-equipped aircraft flying at lower altitudes. The 978 MHz link has what is known as an anonymous mode for pilots flying in visual flight rules (VFR).

ADS-B Out equipment transmits information about the aircraft’s location, ground speed and other data once per second.

General aviation pilots flying below 18,000 feet in VFR while squawking 1200 can enable anonymous mode, which allows the UAT’s transceiver to broadcast a randomized flight ID and a random ICAO address. Once the pilot changes the beacon code from 1200 and/or exits VFR, the transceiver will revert back to the aircraft’s original ICAO address and flight ID.

There are also technological features being integrated into new transponders to address this issue, said Forrest Colliver, managing director of Becker Avionics. The German avionics company manufactures ADS-B transponders and has earned EASA certification on its 1090 MHz BXT 6500 transponders that address the privacy issue.

“We’ve included enhanced privacy settings. We’ve incorporated two features unique to the BXT 6500 family — features used in collaboration with ATC allow the aircraft pilot to disable ADS-B Out or Mode S or both,” said Colliver. “The transponder can revert to operate without ADS-B or even a Mode AC if that is desired and must be done in collaboration with ATC.”

Another major aspect of ADS-B surveillance is that the link is not encrypted, a fact that the FAA readily admits in the ADS-B frequently asked questions (FAQ) section of its Equip ADS-B website. The capability required to encrypt a link being transmitted by airborne aircraft is not quite a reality yet, said Brian Koester, an air transport-rated pilot who represents NBAA at the FAA’s ongoing Equip 2020 meetings. The FAA launched the Equip 2020 initiative in 2014 in an effort to address the equipage issues represented by all different facets of the flight operational community. The group meets four times per year to discuss any of the latest issues that have been observed by commercial airlines and general aviation pilots alike.

“There’s been several concerns proposed by the GA representation at Equip 2020. Our biggest focus has been on privacy,” said Koester.

Representatives for NBAA have also had discussions with business aviation groups it represents. Those groups are also seeking ADS-B solutions that can address their privacy concerns. These groups include the Fallen Warriors, a nonprofit group that occasionally operates flights that connect deceased U.S. veterans with their families so they can have a proper funeral and burial.

“People who oppose the wars started by the U.S. have tracked those planes and met them on the ground with protests, making for a very upsetting situation for their families,” said Koester.

The FAA is taking the issue seriously. In March, the agency conducted a market analysis and welcomed proposals and partnerships with vendors capable of fielding solutions that can address general aviation operators’ privacy concerns. Their goal is to have a “fielded service by December 2018 and seeks partnerships supporting that schedule.” However, as of Oct. 1, the agency has not issued any new updates to that market analysis or its progress with deploying such a service.

Despite the privacy concerns, business aviation operators are still equipping with ADS-B. Duncan Aviation, which has a total of 28 facilities throughout the U.S. providing ADS-B installations, has not seen any resistance to ADS-B equipage as a result of privacy concerns. Matt Nelson, who manages the operations of Duncan Aviation’s avionics installation facilities, said the issue has not stopped installations.

“I had asked some of my people if they had heard of many concerns of this nature,” he said. “They all reported similar results. The subject occasionally comes up in conversation, but it has never been concerning enough to a customer for them to ask any follow-up questions. If this did become a serious discussion, I would likely facilitate a meeting between the operator and a local FAA [principle avionics inspector].”

Operators and ADS-B installation facilities in Europe have similar thoughts. But the regulatory aspect of the ADS-B mandate in Europe is still somewhat unclear, since the region’s civil aviation regulator EASA technically shares responsibility for enforcing ADS-B equipage with local civilian aviation regulatory agencies.

David Van Den Langenbergh, CTO for Luxaviation Group, one of the largest private charter jet and helicopter operators in Europe, said the company’s fleet of aircraft would be ready for the mandate and that he was not aware of the privacy issue.

The issue also was not discussed during the July workshop held by the European Commission when EASA regulators confirmed to airlines, avionics OEMs and representatives of Europe’s general aviation community that the European ADS-B deadline would not budge from June 7, 2020.

The FAA also has confirmed it will be keeping its ADS-B deadline at Jan. 1, 2020. That leaves the business and general aviation community of both regions still seeking a resolution to their privacy concerns.

If there were such a solution available that would allow their Falcon 10 to be visible to air traffic control while being blocked from public tracking, when asked if they would modify their existing solution, both John and Martha King answered emphatically: “Yes absolutely.”

“We teach knowledge courses for about half the people learning to fly around the U.S. We’re very well-known and have people very close to us, but at the same time, you don’t want a crowd showing up every time you arrive at an airport,” said King. AVS