The National Transportation Safety Board is en route to investigate the cause of a Friday crash of a Sikorsky-61 firefighting helicopter owned by Croman Corp. based in White City, according to the U.S. Forest Service.

The National Transportation Safety Board is en route to investigate the cause of a Friday crash of a Sikorsky-61 firefighting helicopter owned by Croman Corp. based in White City, according to the U.S. Forest Service.

However, the investigative team had not arrived by Monday afternoon, said a spokesman at the 6,324-acre Backbone fire on the Klamath National Forest.

The accident, in which both the pilot and copilot were able to walk away, occurred on a forest road in Siskiyou County, Calif., about six miles north of the community of Forks of the Salmon and about 12 miles northeast of Willow Creek. The aircraft was loading a tank of water to dump on the fire when the accident occurred, officials said.

The agency reported the co-pilot was treated and released with very minor injuries, but Croman owner Bud Kaufman said Monday that no one was injured. He declined to give out the names of either occupant.

The aircraft, built about 1970, was substantially damaged but repairable, he said.

The last accident involving a Croman helicopter occurred about seven years ago, he said. That crash didn't involve a Sikorsky.

However, a Sikorsky-61 helicopter owned by Carson Helicopters of Grants Pass crashed last year in Northern California, killing nine firefighters, including six from Jackson and Josephine counties. That 30-year-old aircraft was made in Connecticut and upgraded in 2003 and had been used in firefighting for 10 years.

In August 2006, a pilot and co-pilot died when their Sikorsky CH-54 helicopter crashed into the Klamath River near Happy Camp, Calif.