The Federal Aviation Administration (FAA) granted more than 100 certifications for use of unmanned aerial vehicles (UAVs) by various federal, state and local government agencies last year, and is on pace to approve about 70 applications this year. But some officials are complaining that existing federal regulations are inconsistent and confusing, potentially stymieing their plans for takeoff.

Arguably the most vocal critic on that front is the chairman of the aviation committee for the International Association of Chiefs of Police (IACP), the world's oldest and largest nonprofit group of police executives. Donald Shinnamon, whose day job is public safety chief for the small city of Holly Hill, Fla. just north of Daytona Beach, charges that the FAA is applying its rules inconsistently and defying federal laws about government-operated aircraft.

"There is an immediate need by state and local public safety personnel for unmanned aerial systems," he said at an unmanned systems confab here this week. But by his interpretation, the FAA's rules mean "it's OK to fly a model aircraft but not OK to fly an aircraft in search of a murder suspect" without its permission.

To perform an effective job of aerial surveillance, however, means flying drones at higher altitudes--which takes them directly into the flight path of everything from medical helicopters and Cessnas to commercial jets landing at nearby airports. Pilots don't object to police use of drones, but say they must follow the same rules (including avoidance procedures) and undergo similar certification procedures as airplanes. Police agencies insist that would be too expensive.

Drones have been in use for years by the military and appear to be only growing in popularity. Now they're also becoming alluring to resource-strapped local police departments. They say UAVs can deliver the same--or better--bird's-eye view as a helicopter or airplane, but at a fraction of the cost and with arguably less training and personnel required. (IACP, for its part, hasn't taken an official stance on the issue but is tracking it, a spokeswoman said.)

Say there are swimmers caught in a riptide, and county officials want to send help. It would cost anywhere from $450 to $1,200 per hour for L.A. County Sheriff's Office Commander Charles "Sid" Heal to send one of its helicopters, but a UAV would cost "cents on the dollar," he said. "And if it crashes, it goes into the ocean and floats away."

The FAA admits it is still wrestling with how exactly to keep tabs on the emerging robots' use. It is in the process of finalizing a five-year "road map" for introducing UAVs into the national airspace.

For now, it has imposed a number of rules that attempt to draw lines based on who's operating the UAV and for what purpose.

Civilian or commercial UAV users can apply for an "experimental certificate" that allows flights for research and development or crew-training purposes. (As of late June, the FAA had issued 13 of those documents.) Hobbyists who intend to fly the machines like model airplanes--that is, at altitudes less than 400 feet, away from populated or "noise-sensitive" areas--are generally off the hook.

"Public" users, which include the military and government agencies, are allowed to apply for a permission document known as a Certificate of Waiver or Authorization, or COA for short. They're supposed to show they can control the aircraft in question.

If granted, that certificate allows use of a drone in a defined airspace for a particular period of time, usually up to a year. A COA often contains other restrictions, too, such as limiting flight time to daylight hours or requiring that a ground observer or accompanying "chase" aircraft keep visual contact with the airborne UAV at all times.

Cumbersome certification process

That process is where officials like Shinnamon say the FAA is off the mark. Generally speaking, manned aircraft operated by military or government agencies can be operated without a pilot's license or an "airworthiness" certificate, which governs whether a vehicle is fit to fly. In Shinnamon's view, it's contrary to public aircraft law for the FAA to require UAVs operated by the same entities to go through a different "cumbersome" certification process.

He also took issue with the flight limitations imposed by the certificates, suggesting law enforcement and public safety agents need to be as nimble as possible when incidents occur.

Other proponents of UAV use have argued that if hobbyists are generally off-limits to FAA control, small UAVs operated under similar circumstances should be treated the same. For instance, after L.A. County officials test-launched in a park last summer without prior permission from the FAA, the agency indicated it wasn't allowed.

The occurrence left Commander Heal, who presides over that project, scratching his head. In a telephone interview, he voiced incredulity that, by his interpretation, teenagers could fly model airplanes in the same parks without the FAA's permission but a police-operated drone, which he argued could have "immediate" life-saving applications in his region, had to be certified.

FAA spokeswoman Alison Duquette defended her agency's practices. The decision to require special permission for UAVs reflects what the FAA views as unique risks presented by unmanned vehicles, which the agency believes aren't yet technologically capable of making all the perceptions that a manned craft can.

"Our first role is to do no harm," she said in a telephone interview.

The civilian piloting community would like to see the FAA do even more to rein in UAV use, citing grave concerns about the potential for dangerous collisions.

The Aircraft Owners and Pilots Association (AOPA) has been lobbying for UAVs to be held to the same rules as manned aircraft. The group is also leading a committee under the umbrella of the RTCA, an international aviation standards body, to devise uniform industry guidelines that would likely steer the FAA's own deliberations about new regulations.

UAVs "should be safetly integrated into the national airspace system with other users, and what that means is having some 'see and avoid capability' to detect other aircraft and the ability to communicate with air traffic control stations," AOPA spokeswoman Kathleen Vasconcelos said in a phone interview.

Pilots undergo extensive training on collision detection and avoidance. Planes that fly at night are required to have certain types of lights, for instance. Operating an aircraft near busy airports (in government parlance, "Class B" airports) requires a transponder that broadcasts its altitude. And during all flights that take place in poor weather or higher than 18,000 feet above sea level, the pilot must be in radio contact with controllers.

Last summer, AOPA reported the Gaston County, N.C. police department to federal authorities when it discovered that the officials were flying a small UAV for surveillance purposes without a certificate, which prompted the FAA to prohibit its use.

Privacy advocates have also raised alarms about the idea of new digital eyes patrolling the skies. The Electronic Privacy Information Center's Melissa Ngo, who has written about the privacy implications of increased government use of UAVs, said it's important to sort out a number of questions about the potential for their misuse and abuse.

For instance, authorities tout UAVs as being far quieter than their manned counterparts, which some authorities view as the answer to residents' complaints about helicopter noise levels. But the presence of virtually silent and increasingly smaller machines raises obvious privacy concerns.

"Have state and local police departments spoken to city councils or the public at large about the use of UAVs to watch the general public in everyday activities?" she said in an e-mail interview. "Civilian use of UAVs by state and local police would create a world of constant, unseen surveillance."

Local officials aren't necessarily looking for unfettered UAV-driving rights, Shinnamon said. Ideally, the FAA will be able to work with state and local government officials to come up with UAV-specific regulations, which address things like how high the drones can fly, how far they can travel from their operator, and whether they need to be in the driver's line of sight.

"Once we overcome this regulatory issue, I honestly think the use of this technology will explode at the local government level because it offers just so many benefits to us and the ability to serve our citizens," Shinnamon said.

Heal, whose office tested a drone last year but has not yet secured formal permission to use it, said he doesn't "detect any sense of urgency" on the FAA's part to make its regulations simpler for local officials to follow.

"We're going to do this; this is coming," he said. "And (the FAA) can jump on this train or they can run along behind it, but it is going to leave without them."

CNET News.com's Declan McCullagh contributed to this story.