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Metal fatigue cited in air tanker crashes

/ Source: The Associated Press

Federal safety officials on Friday recommended stricter maintenance and inspection programs for firefighting aircraft after concluding that aging metal caused three fatal air tanker accidents in the past 10 years.

The National Transportation Safety Board said procedures for detecting the problem, known as fatigue cracking, didn’t adequately account for the increased safety risk posed by older firefighting aircraft or the severe stresses those planes encounter.

“We hope the release of these reports will raise operator awareness of the unique problems that affect these specialized aircraft, and the importance of a thorough maintenance program to detect safety issues and prevent accidents,” NTSB Chairman Ellen Engleman Conners said.

In 2002, three members of the crew were killed when a 46-year-old Lockheed C-130A crashed after it lost both wings. Similar problems were found in an aging PB4Y-2 that broke up and crashed fighting a Colorado fire that year, killing both crew members.

Similarity of crashes sparks investigation
The similarities of those crashes prompted the NTSB to reopen its investigation into the 1994 crash of a C-130A, which, like the others, had been converted to a firefighting air tanker. The right wing of that plane came off in flight, killing three people. Witnesses said they saw a flash and then a fireball near where the wing connects to the fuselage.

The NTSB had originally concluded that the explosion was probably caused by fuel that leaked from a pressurized fuel line system and ignited. Since then, the safety board determined the blast was caused by fuel that ignited after the wing separated.

Because the firefighting flights were conducted for the government, they were not required to comply with federal aviation regulations. The safety board sent its recommendations to the agencies responsible for the flights, the Interior Department and the Forest Service.

The Forest Service grounded its fleet after the two crashes in 2002 but developed a new inspection program with Sandia National Laboratories at Albuquerque, N.M., that allowed the agency to reactivate the aircraft.

Current programs called inadequate
The safety board, though, said “currently applicable” maintenance and inspection programs are inadequate.

Telephone calls seeking comment from the Forest Service were not immediately returned.

Interior Department spokesman John Wright said, “We will do what it takes to make these aircraft safe and to improve the safety of our firefighters.”

The safety board also recommended that the Federal Aviation Administration require that firefighting aircraft comply with the stricter maintenance program, although it was unclear whether the agency has the authority to do so.

FAA spokeswoman Laura Brown said the agency would respond to the NTSB within several months. The agency has 90 days to reply.