The Federal Aviation Administration (FAA) this month warned U.S. airports against the use of systems to defeat potential threats from drones, but the agency said when it comes to deploying technologies to detect nearby unmanned aircraft systems (UAS) that present a potential hazard to airport and aircraft operations, operators basically need to do their due diligence in acquiring UAS detection capabilities.

In a May 7 letter to U.S. airport operators, John Dermody, director of the agency’s Office of Airport Safety and Standards, acknowledges their concerns about “errant” drones near their facilities in light of UAS sightings last December near London’s Gatwick airport that resulted in a large number of flights being cancelled or diverted. He didn’t mention alleged drone sightings near an airport in New Jersey earlier this year that also disrupted some flights.

The letter says the matter of using UAS detection systems falls under U.S. Code.

“Entities seeking to evaluate or deploy UAS detection systems should be aware the evaluation or deployment of such systems, even systems that are marketed as passive detection systems, may implicate provisions of law (such as Title 18 of the United States Code) on which the FAA cannot authoritatively opine,” Dermody’s May 7 letter said. Title 18 prohibits the downing of an aircraft in U.S. airspace and also prohibits the use of UAS around airports and aircraft. “Therefore, the FAA cannot confirm the legality of any UAS detection system,” Dermody continued.

The FAA letter puts the issue in front of the Department of Justice, which so far hasn’t said it has an issue with airports using the drone detection systems, Justin Barkowski, staff vice president for Regulatory Affairs at the American Association of Airport Executives, told HSR on May 9.

Dermody also suggested that airports that deploy UAS detection systems should ensure consistency with any grant applications and said they should coordinate with the FAA for technical assistance related to regulatory compliance and to also work with his agency to ensure that any technology they purchase doesn’t “introduce undesirable safety and efficiency impacts.”

Barkowski said that “airports will have to do their due diligence” when acquiring technologies that don’t harm their operations “but it’s definitely a first step towards allowing airports to acquire these systems,” adding that they are “a little bit more encouraged” that they have the authority to do so.

A number of airports, particularly large ones, are interested in the UAS detection systems. Barkowski said the core 30 airports and those just outside that core are most active in either acquiring systems or considering the acquisition of the technologies.

Airports will have to “analyze the products” to ensure they comply with Title 18 and work with the “FAA to make sure they’re not introducing any new hazards in the airport environment but from what we’re hearing behind the scenes, we’re all encouraged that this is going to be the first step.”

Dermody also says the FAA will be following up with more information about UAS detection systems and how best to use them at airports.

The FAA has tested UAS detection systems around airports previously. Those tests, which were completed in Dec. 2017, showed the technology wasn’t “ready for use in domestic civil airport environments,” the agency said in a July 2018 letter to airport sponsors.

Barkowski said that airports also need to work with the FAA as well as their own, and local, law enforcement authorities to develop plans for how to deploy the detection systems and respond when a UAS is detected that could interfere with their operations. Procedures for using the systems will need FAA approval, he said.

One of the attachments to Dermody’s letter says that “Carefully working together, the airport authorities and the FAA, as well as other key stakeholders such as TSA and local law enforcement, can better ensure that airport-specific plans (including any introduction of new technologies such as UAS detection systems) are built around a risk-based, balanced approach that minimizes the potential for the undue impacts on the Nation’s aviation system—which none of us want—including disruption to local air traffic operations and ripple effects that could extend nationally or beyond.”

Dermody’s letter, which included several attachments, was followed by an FAA statement on Wednesday evening warning airports that “the use of non-federal counter-UAS technologies at or around airports … could pose an aviation safety risk by interfering with aircraft navigation and air navigation services.”

In 2018, the Departments of Homeland Security and Justice were granted authorities by Congress to use counter-UAS systems to protect certain critical infrastructures within the U.S. The Departments of Defense and Energy already had limited authorities to use CUAS systems to protect their domestic installations.

DHS was also given authority to test CUAS systems. This testing program is expected to begin this year.

In an attachment to Dermody’s letter, the FAA said that it is working “closely” with DHS, DoJ, DoE and DoD “to support the implementation” of their CUAS authorities, which do not extend “to protect airports. However, DHS and DOJ are assessing how their authorities would cover response to a persistent serious UAS disruption of operations at an airport in the United States.”

Separately this month, the FAA said it will issue a draft rulemaking in July for remote identification of UAS, which would allow the agency, law enforcement officials and other public official to identify drones in their jurisdiction. The draft rule will be provided for public comment before a final rule is published.

The FAA sees Remote ID as essential to development of an unmanned air traffic management system, but the ability to identify and track drones is also viewed as an important component to CUAS operations.