Pilotless planes could be the "next great step forward" in aviation, or a new safety hazard in already crowded skies, a House panel was told Wednesday.
Since 1997, unmanned aircraft have been used in U.S. airspace primarily by the military. But now the government wants to fly more of them to patrol the nation's borders, catch criminals, monitor the environment and assist in disaster relief.
Some companies think pilotless planes have a vast commercial potential for uses that range from crop dusting to weather prediction.
"The development and use of unmanned aircraft is the next great step forward in the evolution of aviation," Nick Sabatini, the Federal Aviation Administration's associate administrator for aviation safety, told the House aviation subcommittee.
But Sabatini didn't disagree with private pilots who say there's no proof that they can operate safely.
The FAA has two basic safety concerns, he said: What happens if the operator on the ground loses contact with the aircraft, and the need for technology to enable aircraft to detect and avoid other aircraft.
Last year, the FAA allowed two unmanned aircraft to be tested for commercial use. Sabatini said 50 other kinds of unmanned aircraft will be approved for flight tests this year.
Robert Owen, a professor at Embry-Riddle Aeronautical University, said the military and private industry want the FAA to fly pilotless planes in U.S. airspace.
"Congress needs to encourage the FAA to streamline and energize its process for granting certificates of authorization for military and commercial operations under appropriate restrictions," Owen said.
The FAA's reluctance to approve unmanned aircraft for commercial reasons "is probably the industry's No. 1 grievance," Owen said.
The military is also chafing under the FAA's restrictions.
Now, when the military or the government wants to fly a pilotless plane in civilian airspace, the FAA allows it to operate over unpopulated areas and be observed by someone on the ground or in a "chase" aircraft.
"We want the Department of Defense to have the same access to the national airspace as commercial aviation," said Dyke Weatherington, deputy of the Unmanned Aircraft Systems Planning Task Force for the Office of the Undersecretary of Defense.
Andrew Cebula, spokesman for the Aircraft Owners and Pilots Association, told lawmakers there hasn't been any testing or demonstration that unmanned aircraft can operate safely in the same airspace as manned aircraft. They can't see and avoid other aircraft, and they can't respond to air traffic controllers' instructions, Cebula said.
One difficulty in regulating pilotless planes is their variety, Sabatini said.
There are drones, which are programmed to fly by themselves, and there are remotely piloted vehicles, which are actively flown by a ground control operator. Some weigh less than a pound, and others have a longer wingspan than a Boeing 737.
Cebula said the FAA must issue new regulations about unmanned aircraft because of already existing confusion over what's allowed.
The sheriff's department in Gaston County, N.C., for example, recently announced it would fly unmanned aerial vehicles for law enforcement purposes. Alarmed pilots told the FAA, which told the sheriff's department it couldn't fly unmanned aircraft over a congested area because it wasn't safe, Sabatini said.
The agency restricts the airspace along the U.S.-Mexico border so that pilotless planes operated by Customs and Border Protection agents can look for people entering the country illegally.
But Cebula said that causes problems for pilots. The flight restrictions begin at 12,000 feet, and pilots sometimes have to fly that high to make radio contact with air traffic controllers.
Lawmakers were reviewing the government's authority to oversee the safety of unmanned aircraft in civilian airspace.