The crash that killed former Sen. Ted Stevens served as another tragic reminder about the dangers of flying in Alaska, where general aviation accident rates are more than twice the national average.

For many Alaskans, flying hundreds of miles to larger cities for shopping and errands is as common as taxis and buses might be to urban dwellers, exposing residents to a litany of hazards including treacherous mountain passes and volatile weather.

A clear flight can quickly turn into a nightmare of clouds, rain and wind as pilots navigate tricky mountain ranges, glaciers and meandering rivers. Pilots often rely on sled dog trails, rivers, mountains or a familiar tree to keep them on track.

"A lot of the stuff is not what you'd find down in the Lower 48," said John Bouker, the owner of Bristol Bay Air Service who has logged 30,000 hours in his career. "It's not just a simple matter that you got your license, you went through all the classes. You got to know where you're going, man."

Stevens was so mindful of the risks that he once called plane crashes an occupational hazard for politicians in Alaska, and he spoke from experience. He survived a plane crash in 1978 that killed his wife.

Stevens and four others died Monday when their float plane slammed into a mountainside, and federal investigators are examining weather patterns and the wreckage from the accident to understand what caused the crash. Four passengers survived, including former NASA chief Sean O'Keefe and two teenagers.

The crash happened as the fishing party traveled from a lodge to a nearby salmon camp, and, as in most of Alaska, flying was really the only way to get there.

More than 80 percent of Alaska's communities, including the state capital of Juneau, are not connected to highways or road systems, making travel by air or water an essential.

Aviation data analyzed by the Aircraft Owners and Pilots Association's Air Safety Foundation found a rate of 13.59 accidents per 100,000 flight hours in Alaska between 2004 and 2008. The comparative national rate for smaller general aviation aircraft was 5.85 accidents per 100,000 flight hours.

That means Alaska's accident rate was more than two times higher than the national average, according to the figures.

Alaska had 515 small plane accidents from 2004 to 2008, making up 6 percent of the 8,010 crashes nationally in that period, the analyzed federal data shows. By comparison, Alaska makes up about 2 percent of the U.S. population.

Alaska has had several deadly plane crashes in the last couple months alone, inclduing accidents at Denali National Park, Elmendorf Air Force Base and in a busy business district near downtown Anchorage that killed eight people in all.

Laura Washington lives in the Inupiat Eskimo village of Buckland, 40 miles from the Arctic Circle. There are no roads leading to the community of 425 people.

Several times a year, Washington visits Anchorage more than 500 miles to the southeast for shopping, major medical appointments or to watch sporting events. But first, she has to catch a small plane north to the hub town of Kotzebue. From there, she catches a larger plane to Alaska's largest city.

During the winters, people use snowmobiles for some travel, but the need for planes never goes away.

"They're the only way to get around to places you need to get to you can't drive to," Sam Brannon said Wednesday while waiting for an air taxi in Dillingham, near the site of the Stevens crash.

Making matters more challenging is the fact that the state has relatively few weather stations that can provide crucial information about conditions in the air.

"Alaska's very challenging to fly in," said Valerie Jokela, a dog musher from Anchorage who flew for years and now also works with the Federal Aviation Administration. "There are mostly mountain ranges that generate their own weather, and mountain passes, and glaciers — and glaciers make their own weather, too."

In an unusual twist to this week's tragedy, Stevens had been a vocal advocate of a federal project to equip airplanes with new technology to provide pilots with better weather information.

The technology, hailed by FAA as "the future of air traffic control," is called Automatic Dependent Surveillance-Broadcast. It's meant to help replace the radar that pilots and controllers now rely on with GPS technology that allows them to see on cockpit displays concise weather information and location of other aircraft in the area.

Speaking about the Capstone program in 2002, Stevens said: "The Capstone program can prevent controlled flight into terrain as well as collisions and other accidents better than any other technology I've seen."

Plans currently call for all aircraft flying within certain controlled air space to be equipped with the technology by 2020, FAA spokeswoman Tammy Jones said.

Alaska was one of the first test sites for the program. It can cost from $7,600 to $10,900 to equip a general aviation aircraft with the technology, the FAA says.

Jim La Belle, regional director for the National Transportation Safety Board, told The Associated Press that the plane Stevens was on was not outfitted with that technology. It's still not known if the technology could have prevented the crash involving the 1957 float plane.

Without such technology, pilots frequently turn to visual elements to guide them through treacherous terrain.

"The No. 1 rule is you don't lose the ground," Bouker said. "And you better know where you're at or you're in trouble."


Associated Press Writer Mark Thiessen contributed to this report from Dillingham, Alaska. D'Oro contributed from Anchorage.