The use of drones could revolutionize business, government and law enforcement. Imagine, for example, small unmanned aircraft flying low to the ground to deliver precise measures of pesticides to agricultural fields, reducing the amount of dangerous chemicals used. Drones already have proved useful in search-and-rescue operations, combing large areas of inaccessible backcountry that manned planes and helicopters can't get to safely.

But as drones make the transition from military device to civilian tool, they also threaten to bring a new level of intrusion into what little privacy remains to us in the Internet era.

The public is understandably nervous. It was bad enough, many felt, when Google Maps collected images street by street, putting people's homes and cars online for everyone to see, not to mention catching them coming out of strip clubs and doing other embarrassing things. With drones, would police and businesses be able to peek into Americans' backyards and even into their windows? Would people be routinely monitored, taking their kids to the park or going camping in the woods? In June, after a few incidents in which visitors were dangerously buzzed by private drones and a herd of bighorn sheep scattered at the approach of the low-flying aircraft, the National Park Service imposed a temporary ban.

Relatively few drones are flying legally these days; federal legislation allowing drone flight will not take effect until the Federal Aviation Administration produces a plan, due Sept. 15, to integrate unmanned craft into the airspace. That plan will address such safety issues as making sure the drones are air-worthy, that their remote pilots are properly trained and that a system exists to prevent collisions. It will not, however, address the more delicate issue of privacy. Instead, dozens of states, including California, have been considering their own restrictions. Virginia was first to regulate use of drones, imposing a near-moratorium for two years on police use of drones except in search-and-rescue operations and certain life-or-death emergencies.

California's legislation is more modest. Like Virginia's law, the bill by Assemblyman Jeff Gorell (R-Camarillo) would allow law enforcement to use drones in emergencies. But it would also let police use them for surveillance by obtaining a search warrant in advance. Other public agencies would be allowed unrestricted use of drones, but only to perform their core missions. In other words, the Coastal Commission might use the devices to survey coastal erosion and beach access, or Caltrans might build a record of traffic patterns.

The bill, AB 1327, has had broad support in both parties. It is scheduled to go to the Senate floor in August, its last legislative hurdle. It deserves to be approved and signed into law, with minor adjustments.

Predictably, law enforcement agencies object to the bill's restrictions. The California State Sheriffs' Assn. would prefer to deploy drones under the same rules that govern helicopter use, which would mean, in most cases, that no warrant would be required for surveillance.

But drones are different from helicopters. For one thing, the high cost of purchasing and operating helicopters naturally restricts their use. Drones are cheaper, require less manpower, can stay airborne longer and can fly lower — meaning that surveillance could be far more common, more invasive and more continual.

In addition, new-generation drones will be smaller — perhaps the size of a hummingbird — which would make it easier to spy on people without their knowledge. It's hard to hide a noise-blasting helicopter that's hovering over a backyard. The sheriff's group is on more solid ground when it suggests that drones could be useful in monitoring large public events such as marathons, marches and parades, where the public has no expectation of privacy and drones could help protect public safety. Gorell should consider allowing this.

This bill is only a start. Far more drone regulation will be needed in future years as society learns more about the uses — and misuses — of unmanned aircraft. Next on the Legislature's to-do list should be reasonable restrictions on private and commercial use of drones in order to further protect the safety and privacy of state residents.

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