SEATTLE (AP) - The aircraft part suspected of causing January's deadly Alaska Airlines crash was discovered to be worn down in a 1997 inspection but fell one-thousandth of an inch short of requiring regular tests, The Seattle Times reported Sunday.
If it were not for that microscopic margin, Alaska would have been required to closely monitor the jackscrew assembly on the MD-83, the Times reported.
Alaska Airlines mechanics had recommended replacing the worn jackscrew assembly, which is the focus of the crash investigation by the National Transportation Safety Board. But the mechanics were then told to re-evaluate the part, and that produced the measurement indicating it was barely within safety limits, the Times said.
The 1997 test has become the focus of a criminal investigation of the airline's maintenance practices by the FBI and the Department of Transportation. They are trying to determine whether the test result was legitimate or was manipulated by company workers to get the plane back into service without further inspections, the newspaper said.
Flight 261 was en route to San Francisco and Seattle from Puerto Vallarta, Mexico, when it crashed Jan. 31 into the Pacific Ocean just off Los Angeles, killing all 88 people aboard.
The pilots had reported problems with the plane's horizontal stabilizer, a flap on the tail that is tilted by the jackscrew assembly to determine the pitch of the aircraft.
Mechanics had tested the jackscrew assembly seven times within a few days in 1997.
The first test - during a major check at the company's Oakland, Calif., maintenance facility - found the part to be close to its maximum wear limit, with .040 inches of deterioration on the threads. Had that measurement been any higher, the airline would have been required by its own FAA-approved rules to replace the part.
Following that test, mechanics recommended replacing the part, the Times said, citing federal officials and an Alaska employee who have seen the maintenance records. But a written order to replace the part was scratched out and replaced with a directive to re-evaluate the finding.
Subsequent tests apparently showed less wear on the part - a finding of .033 inches of deterioration. At .034 inches of wear - just .001 inch more - the part is to be rechecked after every 1,000 flight hours, according to an Alaska maintenance manual, the Times said. That would have meant the part would have been inspected repeatedly in the 28 months between the tests and the crash.
But at .033 inches of wear, the jackscrew was not due for inspection until June 2000. The plane did undergo a major maintenance check in January 1999, but the jackscrew assembly, which is inspected only in alternate major checks, was not part of that.
Alaska officials have said the part was well within standards.
''We stand by what we said before,'' Alaska spokesman Jack Evans said Sunday. He said company lawyers have advised employees not to comment because of the criminal investigation.
The FAA had no comment Sunday because the accident remains under investigation, spokesman Eliot Brenner said.