The Federal Aviation Administration has no current plan to reclassify low-altitude airspace to accommodate small drones. “But that doesn’t mean we haven’t done significant analysis,” an FAA executive said May 2.

Speaking during an “Airspace Integration and Policy Panel” at the Xponential 2016 conference in New Orleans, Randy Willis, manager of the FAA Air Traffic Organization emerging technologies team, said the pace of change in unmanned aircraft systems (UAS) makes it difficult to establish an airspace structure to safely manage them with other air traffic. Last year, Amazon proposed segregating the airspace below 500 feet for use by small drones, effectively separating them from manned aircraft. Both Amazon and research laboratory Google X have advanced the idea of third-party airspace service providers managing drone traffic in place of the FAA.

On May 3 at the conference, Harris Corporation, which manages the ground infrastructure for automatic dependent surveillance-broadcast (ADS-B) in the U.S., unveiled an “ADS-B Xtend” service that will help operators and airspace managers track drones flying below 500 feet. The system “features a networked, dual-band receiver and relay system that can be attached to existing structures or to mobile vehicles for roaming coverage,” Harris said.

Nevertheless, any airspace restructuring to accommodate drones would call for a federal rulemaking process, Willis advised. “We don’t want to guess; we don’t want to shoot at something and it’s not going to work,” he said. “A change in airspace structure is a rulemaking procedure, so we’re very cautious of moving forward in that area. We’re still assessing at this point.”

The FAA’s decision-making process will be informed by a low-altitude system NASA is developing through the UAS traffic management (UTM) effort, Willis said. The space agency has said that it will turn over its UTM research to the FAA in 2019.

Parimal Kopardekar, who leads the UTM effort as manager of NASA’s Safe Autonomous Systems Operations Project, also participated on the panel. “Whatever way of [managing] this traffic we come up with has to scale to the future,” Kopardekar said, noting that the FAA has projected sales of some 2.7 million commercial drones by 2020. In a sales forecast it prepared for the drone registration rule released in December, the FAA also projected sales of 4.3 million hobby drones by that time.

One area in which the FAA is moving forward is on ATC procedures for larger UAS, Willis said. For example, the agency has reserved the transponder code “7400” to notify controllers of a “lost link” emergency when the radio frequency command and control link to an unmanned aircraft is lost or disrupted.