“The challenge is there is no track record of how safe these systems are,” says Cathy Cahill, director of the University of Alaska’s Center for Unmanned Aircraft Systems Integration. “The FAA’s rules and regulations have been written in blood. And they do not want to write more in blood. So what they’re doing is being very cautious.”

The FAA’s first concern is the safety of the flight systems themselves—whether or not an autonomous system will simply fall out of the sky. But the bigger issue, Cahill explains, is what’s referred to as “command and control”—the relationship between a pilot on the ground and the robot in the sky. Autonomous systems that travel beyond their operator’s line of sight depend on a data link between the plane and the controller on the ground. That allows the controller to change the flight path at the request of air traffic control, and keep an eye on the plane’s surroundings using cameras on board. The FAA wants to know how remote operators plan to make that connection stick, so that the bird isn’t left flying blind. One answer is redundancy. In the Arctic, where Cahill’s team sends drones to inspect pipelines and photograph ice seal pups, the aircraft are linked back to the ground by three different channels, including an Iridium satellite and two radio links.

But what if all those links get caught off? Cahill’s team has been working with the FAA to validate so-called detect-and-avoid systems that identify airborne hazards. These run the gamut from acoustics to radar to visual and infrared cameras. The task is simpler than, say, putting self-driving cars on the roads, she notes, with inconvenient pedestrians and rule-flouting human drivers. But the consequences of a mistake are more dire. She says the technology is close, but not proven yet for wide scale use. Xwing, with the aerospace company Bell and funding from NASA, has developed its own system that it plans to demonstrate this fall.

Still, there’s incremental progress, Cahill says, with case-by-case approval that permits operators to run flights beyond the operator’s line of sight at a particular time and place. Last year, the FAA gave that permission to both UPS and Wing, a subsidiary of Google’s parent Alphabet, for small drones—primarily for moving blood and medical supplies. “It used to be you proposed one of these operations and the answer was ‘hell no.’ And then it went to ‘no.’ And then it was a ‘maybe.’ And now it’s gotten to ‘yes,’” she says. It’s unclear what the FAA will make of larger aircraft, like the Cessna, she says, but she notes they might be more comfortable with the familiar workhorse of the skies. She’d personally love autonomous Cessnas to deliver packages in rural Alaska, where she lives; the major cargo airline delivering there went bankrupt last year, and human piloted flights are both expensive and dangerous. “For us it’s an immediate need,” she adds.

Piette’s vision of a sky buzzing with drones will likely need to wait. “I think the next jump everyone wants is going to take more time,” Cahill says. “I think it will be in the next five to 10 years.” That’s because it will take real infrastructure. Think comprehensive networks of redundant data links into the national airspace, and secured from hackers. There will be studies of how pilots should be trained and how many planes they can handle. And in all likelihood, a much bigger public debate about where and how those systems can be used.

In the meantime, the humans remain aboard. As we bank serenely over the San Joaquin-Sacramento Delta, Gariel sits in the back of the plane in front of two screens, acting the role of the ground-based “pilot.” The detection system picks up a few small aircraft in our sight, warning where we shouldn’t go, to avoid interfering with the other planes. But it’s a quiet day, and there are no imminent threats. In fact, there isn’t much for Gariel to do at all. He admits the flights get a little boring, sometimes. But he hopes for many more boring flights ahead, flights that would prove he wasn’t needed up here at all. In the meantime, he muses, perhaps he could start skydiving back to the tarmac.

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