WASHINGTON – A firefighting helicopter crash that killed nine people two years ago was caused by deceptions on the part of the company that leased the aircraft to the U.S. Forest Service and a lack of federal safety oversight, the National Transportation Safety Board determined Tuesday.
Carson Helicopters of Grants Pass, Ore., intentionally altered documents to exaggerate the helicopter's performance capabilities in order to win a Forest Service contract, the board said.
But the Federal Aviation Administration and the Forest Service missed several opportunities to uncover those problems, the board said.
"This accident had more to do with Carson's actions than the oversight entities' inactions," NTSB chairman Deborah Hersman said. "But the FAA and the Forest Service didn't hold up their end of the deal to oversee Carson's actions."
The accident points to a larger problem of a lack of safety oversight of nonmilitary aircraft operations by federal, state and local government agencies, board members said. FAA has said it doesn't have the authority to oversee the aircraft operations of other agencies.
Government aircraft operations "have no parent and no one wants to be responsible for them," Hersman said.
NTSB has alerted the Department of Transportation's Inspector General that Carson's actions may merit a criminal investigation, Hersman said.
The board's investigation showed the Sikorsky S-61N helicopter weighed 19,008 pounds when pilots tried to take off from a rugged mountaintop clearing near Weaverville, Calif., on Aug. 5, 2008. But the maximum weight to lift off at full power with no margin to spare was 18,445 pounds, they said. If Forest Service guidelines — which include a safety margin — had been followed, the weight shouldn't have exceeded 15,840 pounds, investigators said.
Carson also provided its pilots with procedures for estimating liftoff weight that eroded safety margins, the board said.
Two months after the accident, the FAA office in charge of overseeing Carson received letters from two pilots with knowledge of Carson's operations who expressed concern that the company was miscalculating helicopter weights, investigators said.
Investigators said that if FAA had provided NTSB with that information at the time, it would have helped them figure out sooner that the weight calculations were faulty. FAA was a party to the accident investigation and its inspectors were aware of the investigation, they said.
However, FAA dismissed the allegations and didn't provide the letters to NTSB until about a year later after the investigators made a general request for documents related to the agency's oversight of Carson after the crash, investigators said.
Carson has surrendered its FAA certificate, the agency said in a statement released after the board meeting. The certificate is the equivalent of an operating license. FAA is also working on clarifying its policy on oversight of government aircraft, the statement said.
The Forest Service said in a statement that it is committed to learn from such tragedies and has "aggressively pursued opportunities to improve its operations from the onset of this accident."
Carson Helicopters issued a statement saying it believes the cause of the crash was a loss of power to the No. 2 engine due to the failure of a fuel control unit while the helicopter was taking off. The company added that their own inquiry uncovered a history of problems with the fuel control unit on the Sikorsky S-61N helicopter.
However, NTSB said it didn't find that problem in this accident.
The helicopter was airborne less than a minute when the rotor began to slow, it clipped a tree and fell into the forest. It was carrying firefighters from the front lines of a stubborn wildfire in the Trinity Alps Wilderness.
Seven firefighters, the pilot and a Forest Service safety inspector were killed. The co-pilot and three firefighters were injured. Survivors told the board that they were unable to unbuckle their seatbelts and had to wiggle out of them to escape the downed helicopter before it was consumed in a post-crash fire. They also told the board that they believe some of those who died were still alive after the crash but were unable to escape.
FAA officials have said they don't have the authority to regulate safety of aircraft leased or owned by other federal agencies or state and local government agencies if the aircraft are dedicated exclusively to government operations.
Twenty-three federal agencies, including the Forest Service, operate 1,632 nonmilitary planes and helicopters, according to the General Services Administration. Some are owned and maintained by the government, while others are leased from private companies such as Carson. Hundreds more are operated by state and local governments.
Federal agencies have policies that leased aircraft should come from companies that have been certified by the FAA, according to the GSA. But FAA limits its inspections and oversight to the portions of the leasing companies' operations that don't involve government leases, investigators said.
Part of the reason for that is that FAA has no expertise in many of the kinds of operations that government aircraft are involved in, such as firefighting, investigators said.
Fatal accidents involving government aircraft are commonplace. A 2001 study by the board said there were 341 accidents involving nonmilitary government aircraft between 1993 and 2000.
Among accidents in the last two years:
— A Forest Service plane conducting an aerial survey of tree defoliation in southwestern Pennsylvania in June struck a light post while trying to land near Lock Haven, Pa. The pilot and two Forest Service employees were killed.
— A California Fish and Game Department helicopter surveying deer collided with power lines near Fresno, Calif., in January. The pilot and three passengers were killed.
— Also in January, a U.S. Fish and Wildlife Service helicopter on a repositioning flight crashed northwest of Corvallis, Ore., killing the pilot and a passenger.
— A New Mexico State Police search and rescue helicopter that had just retrieved a lost hiker crashed into a hillside near Santa Fe in June 2009. The pilot and the hiker were killed; a patrolman acting as a spotter was seriously injured.
National Transportation Safety Board www.ntsb.gov