SAN FRANCISCO - As wildfire season begins in Western landscapes that were covered in smoky haze for weeks at a time last summer, the federal government's professional firefighters are exploring the idea of replacing manned surveillance aircraft.
Infrared cameras on remote-controlled drones - with a maximum wingspan of about 52 inches - could map a fire's size, movement and speed, and identify hot spots, a particular danger to firefighters.
Federal agencies are looking at how much value drones would bring to firefighting methods.
"We're trying to get them in the mix and put them out in the field to see the potential," said John Gould, the Bureau of Land Management aviation chief at the National Interagency Fire Center in Boise.
But the use of drones in open airspace is regulated by the Federal Aviation Administration, and its safety requirements effectively preclude unmanned aerial systems, or UAS's, from operating out of sight of a ground-based pilot. If distance or the smoke of a wildfire obscures a drone from observers on the ground, a manned aircraft must be sent aloft to keep an eye on it.
"In terms of federal regulations right now, we can't use UAS's out there except on a very limited basis," said Ron Hanks, the aviation safety and training officer at the federal Forest Service.
Rusty Warbis, flight operations manager at the Bureau of Land Management, said the approval process is "cumbersome," though improving.
The evaluations by wildfire experts are part of larger questions on how to incorporate these aircraft, originally used for military purposes, into civilian missions. In the case of wild-land fires, their observational abilities could eliminate the risk to pilots and improve the safety of firefighters.
But their presence also could complicate the government's ability to ensure the safety of the country's airspace, which is the FAA's main concern. And observers in Congress believe that inherent distrust of government and privacy concerns are also slowing the introduction of firefighting drones.
Their potential usefulness, particularly their ability to pinpoint hot spots and fly in thick smoke that would ground other aircraft, was shown in an Alaskan fire nearly four years ago.
The fire, which burned more than 447,000 acres northeast of Fairbanks, was generating so much smoke that no planes were permitted to fly. But a drone belonging to the University of Alaska, Fairbanks, was launched and easily identified the extent of the blaze and its varying levels of heat.
"The smoke was so thick ... that's why they came to us," said Rosanne Bailey, a retired Air Force brigadier general who is the deputy director of the Alaska Center for Unmanned Aircraft Systems Integration at the university. "We could fly and see the borders of the fire using infrared."
Other uses, she said, could include using an aircraft "as a communications node, to enable firefighters in remote areas to give and get information" in remote terrain where cellphone and radio connections are nonexistent.
Kent Slaughter, the acting manager of the Bureau of Land Management's Alaska Fire Service, said it took four days to get the FAA's approval for that flight in 2009; the process is now about 24 hours.
But privacy concerns are slowing the integration of unmanned vehicles into the firefighters' tool kit, said Sen. Mark Begich, a freshman Democrat from Alaska.
"Firefighting is a great example of how unmanned aircraft" are able "to determine the range of a fire, the intensity of a fire, without jeopardizing lives," he said. "That's a unique application, especially in my state, in Colorado, in California."
He called the delays in getting approvals for testing the craft "frustrating." The reason cited most often by firefighting experts is the requirement that the aircraft be followed and monitored by a chase plane if ground observers cannot see them through smoke, or because they are flying into canyons in steep and rugged terrain.
The Interior Department's discussions with the FAA are continuing. Les Dorr, an FAA spokesman, said that safety in the air and on the ground is paramount and that the issue of line-of-sight requirements for drone use is being carefully studied.
The Army has lent the Interior Department 41 small drones that have been used for environmental monitoring, including tracking migratory wildfowl.
The Forest Service, part of the Department of Agriculture, has also been studying drone use for years.
"We are still developing policies internally, what the cost-benefit would be," Hanks said. The drones, he said, "would be competing against what we could do aerially against a helicopter or a light fixed-wing airplane."