If I Fly a UAV Over My Neighbor's House, Is It Trespassing?

Even a toy drone with an HD camera scrambles our sense of property and privacy rights.

The AR.Drone.2.0 in action in my backyard.

My poor kitten, who my unfortunate Instagram contacts know too well, gets beat up every time he goes outside. There's a bully cat in the neighborhood who appears to relish in attacking cute, fluffy things as soon as they get out of human oversight. So, naturally, I bought a Parrot AR.Drone.2.0, a remote-controlled quadcopter with an HD camera attached, to see if I could spot where the punk bully cat hangs out.

Notes and Dispatches from the Frontiers of Creativity
See full coverage

After some training runs in which I crashed the little UAV every fifteen seconds, I started to get the hang of where to push on my iPad to get the little AR.Drone to go the way I desired. And then, dodging trees and power lines, I sent the machine flying higher in the sky and scooted towards the fence, popped over it, and -- terrified of crashing in territory I didn't control -- sped back across to the safety of my own backyard, and engaged the automatic landing sequence.

Technically, I'd gone over the fence line, and if I'd done so on foot, intentionally, I would have nominally been guilty of trespassing. But if I were flying in a helicopter, a few hundred feet up, I would *not* have been guilty of trespassing. So, what about the air in between?

There aren't many specific laws or cases on the books to address my specific situation, but we do know that the idea of airspace has changed in the decades since humans started flying around.

"Once upon a time, you had the rights to your property under the soil and to the sky.  It went by the colorful, Latin label "ad coelum et ad inferos"---to the heavens and hell," Ryan Calo, a University of Washington law professor and former research director of Stanford's Center for Internet and Society, told me. "But subsequent case law recognized the limits imposed by commercial aviation and other realities of the modern world.  Now you own the air and soil rights you might reasonably use and enjoy."

That original dictum -- ad coelum et ad inferos -- was never part of legislation, but rather passed to us from British common law. The process by which this notion of property was limited really began in the early twentieth century, when we began to regularly reach into the heavens and nominally closer to hell. Timothy Ravich is an aviation lawyer who contributed an article to the North Dakota Law Review (UND is a major hub of civilian aerospace training) on "the integration of unmanned aerial vehicles into the national airspace." I figured if anyone knew the legal status of my neighborhood flights, it would be him.

"If you were to take your Parrot drone over my house, I suppose at one level, it is a trespass," he said. "You were not invited there and could potentially have disrupted my quiet enjoyment of my home. I suppose I could sue."

Whoops, I thought. But it's not really that simple. Regardless of whether someone technically had the right to stop me from flying my little UAV over a house, "It's quite another thing to exercise those rights in a court of law," Ravitch said. "If someone does take a Parrot and fly it over your house every day for a year. Are you injured? What are the actual damages?"

In other words: what are you gonna do about it?

"What [property] rights you have beyond what you can physically touch has always been difficult for the law to grapple with," Ravich told me.

"Good fences make good neighbors," Ravitch said. "But we don't build fences in the air."

The drone's eye view, sadly no Bully Cat in sight.

There are two fascinating analogous cases to look at. The first reaches all the way back to the early 1800s, when balloonists (!) were first making their uncertain journeys skyward. In 1822, the Supreme Court of New York heard the case of Guille vs. Swan. Guille was a balloonist. Swan had a vegetable garden. Guille launched himself in a balloon near Swan's patch and as he descended, hilarity/mayhem ensued. Here's the court's description of the situation:

The facts were that Guille ascended in a balloon in the vicinity of Swan's garden and descended into his garden. When he descended his body was hanging out of the car of the balloon in a very perilous situation and he called to a person at work in Swan's field to help him in a voice audible to the pursuing crowd. After the balloon descended it dragged along over potatoes and radishes about thirty feet when Guille was taken out. The balloon was carried to a barn at the further end of the premises. When the balloon descended more than two hundred persons broke into Swan's garden through the fences and came on his premises beating down his vegetables and flowers. 

Guille was found liable both for the damage his own balloon caused and the damage perpetrated by the crowd following him. But in that case, the problem was not the flight over Swan's veggies, but its descent back down where property rights make more sense.

The real touch point for UAV law in civilian air space, though, is the case of United States v. Causby, which the Supreme Court heard in 1946. It demolished, "ad coelum et ad inferos." The Thomas and Tinie Causby owned a few acres of land near Greensboro, North Carolina on which they farmed chickens. It happened to be underneath one of the glide paths to a municipal airport, so planes passed roughly 83 feet above his property. The planes -- old-school bombers and fighters in many cases -- scared the wits out of his chickens. They literally killed themselves flying off the walls in fright. "As many as six to ten of their chickens were killed in one day by flying into the walls from fright. The total chickens lost in that manner was about 150," the Court noted. Production also fell off. The result was the destruction of the use of the property as a commercial chicken farm."

What resulted from this set of circumstances, though, was a triumph for aviators. The Court affirmed that "the air above the minimum safe altitude of flight... is a public highway and part of the public domain." Poor Causby and his chickens were out of luck.

[The] doctrine [of cujus est solum ejus est usque ad coelum] has no place in the modern world.  The air is a public highway, as Congress has declared.  Were that not true, every transcontinental flight would subject the operator to countless trespass suits.  Common sense revolts at the idea.  To recognize such private claims to the airspace would clog these highways, seriously interfere with their control and development in the public interest, and transfer into private ownership that to which only the public has a just claim.

The question remains: what do private citizens and the public have just claims to? The reasoning of the court in these old decisions is one that I like: the air should be a space for everyone, not whoever can purchase the most square acreage on the ground.

But the wide availability of UAV technology (combined with HD video) scrambles my sense of what is right. Specifically, it points out how much of our sense of privacy is intimately connected up with our expectations of our property rights. Drones -- as flying, seeing objects -- scramble our 2D sense of property boundaries, and along the way, make privacy much more complicated.

"This idea of a reasonable expectation of privacy has always been accepted as the standard and the interface of that privacy right and emerging UAV technology is fascinating," Ravitch said. "There is not an answer. The best we can do is arrive at laws and practices of the then-existing sensibilities of the population."

Because while my hunt for the neighborhood's bully cat is a lighthearted endeavor, the real difficult decisions in this domain will come when local police have as many unmanned aerial systems as they do trained dogs.