Computer Warning 3 Days After Alaska Airlines Crash

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Washington -- An Alaska Airlines computer
alerted the carrier to check the jackscrews of its
MD-80 planes for problems three days after Flight
261 slammed into the Pacific Ocean, killing all 88
people aboard, an airline official testified today.

SF Gate

-- Anonymous, December 16, 2000

Answers

3 other worn jackscrews found before jet crash

WASHINGTON -- Alaska Airlines replaced worn jackscrews in three of its planes only months before the crash of Flight 261.

Three days after Alaska Flight 261 plunged into the Pacific, an automated computer program alerted the airline to potential wear problems with the part that failed and caused the crash, an airline official testified yesterday.

The three jackscrews were replaced within a five-month span in 1999. This was the first time since Alaska began operating the McDonnell Douglas MD-80 series jets in 1985 that it had had to replace even one of the jackscrews, a key control mechanism in the tail.

The jackscrew problem surfaced after the airline switched lubricating grease and after it stretched the time between wear checks on the jackscrew as well as the interval for lubricating it.

"Unfortunately, it (the computer) did not react in time to tip us off there may be a problem with the jackscrews," Wright McCartney, reliability and maintenance program manager for Alaska, said of the computer-generated maintenance alert.

Testifying before the National Transportation Safety Board, McCartney said the alert did not suggest the kind of catastrophic jackscrew failure that occurred on Flight 261, so even if the alert had been issued earlier, it would not have predicted the crash.

"Never in the history of the industry . . . has there been a catastrophic failure of a jackscrew like occurred in this aircraft," he said. "I don't see how we could predict it, no."

Still, the revelations yesterday stunned family members attending the board's first public hearings into the crash.

"It was really disturbing . . . very upsetting," said Claire Barnett of Seattle, whose two daughters, Cori and Blake Barnett Clemetson, died in the crash Jan. 31, along with 86 others. More than half the victims were from the Seattle area.

Another family member, who asked not to be quoted by name, said she was "angry and dismayed" by what she has heard, not just yesterday, but since the hearings began Wednesday.

Alaska had 35 MD-80 jets in its fleet before the crash of Flight 261, so the three jets with the worn jackscrews represented nearly 10 percent of the carrier's total fleet.

Investigators believe the jackscrew mechanism in the plane that crashed failed because it was badly worn and may have lacked adequate lubrication.

A lead mechanic had ordered the jackscrew be replaced during a heavy maintenance check of the same plane at Alaska's Oakland, Calif., facility Sept. 27, 1997, but it was left in the plane after being retested by other mechanics and determined to be well within wear limits.

Questions have been raised by investigators about whether the $60,000 jackscrew assembly may have been left in the plane because replacing it would have delayed the jet's return to service, an allegation that Alaska officials have strongly denied. A federal grand jury in Oakland is looking into the matter as part of a criminal investigation that is separate from the crash inquiry by the safety board, which will not issue its final report on the crash, including the probable cause, until later next year.

Two witnesses were asked questions yesterday about the mechanics' decision not to replace the jackscrew of the jet that later crashed. One of them, Robert Hinman, received immunity from prosecution from the Justice Department before he would agree to testify.

Hinman was formerly director of base maintenance at Alaska's Oakland facility. He retired Oct. 1.

Jackscrews on MD-80s must be replaced if a so-called "end-play" check shows more than 0.040 of an inch of wear. The first test on the ill-fated jetliner found exactly forty-thousandths of an inch wear, and lead mechanic, John Liotine, ordered that it be replaced.

Hinman said he was not familiar with that order in September 1997. He also said he did not know if a replacement jackscrew was in Alaska's inventory at the time, or if the part would have to have been ordered. That would have kept the jet out of service for an even longer time.

But a couple days after the original inspection, another mechanics rechecked the jackscrew and got measurements that fell well within the wear limits. So the jackscrew was not replaced. The jet was returned to service.

Richard Rodriguez, the NTSB investigator in charge of the Flight 261 crash, pressed Hinman about those subsequent tests.

"Why would someone remeasure that? Isn't that a waste of manpower?" Rodriguez asked.

Hinman said he had no knowledge about the decision.

Art Fitzpatrick, director of base maintenance for Alaska and formerly line maintenance director in Oakland, also said he had no knowledge about the decision not to replace the jackscrew. Like Hinman, he said he did not know if there was a replacement jackscrew in Alaska's inventory.

When asked why the jackscrew had to be retested several times, Fitzpatrick said it was his understanding that the initial test had been performed by an "inexperienced" mechanic.

In testimony earlier, McCartney said maintenance workers first noticed unusual wear on the jackscrew of a MD-80 that was undergoing heavy maintenance in June 1999. That jackscrew failed the end-play test.

In November 1999, the jackscrew of a second Alaska plane was replaced after it failed the end-play test during a heavy maintenance.

A third jackscrew was removed in November during a heavy maintenance check by a third party in Phoenix. But the replacement part was not installed until January of this year.

After all those planes were returned to service -- the last in January -- a computer-generated statistical analysis of maintenance triggered an alert Feb. 3, just three days after the Flight 261 crash.

That formal alert meant mechanics were to pay particular attention to the condition -- and lubrication -- of jackscrews.

McCartney's testimony came on the third day of the NTSB's hearing into the crash and on a day when the pace quickened considerably. In addition to McCartney, the NTSB heard from witnesses about Alaska Airlines' decision to use a different kind of grease to lubricate the jackscrew.

Later in the day, the panel examined the airline's maintenance procedures.

As on previous days, however, the NTSB's gaze remained fixed on the jackscrew assembly and the stabilizer at the rear of the plane it controls. While investigators believe a failed jackscrew caused the crash, they are unsure about the conditions that caused the part to fail. A prime goal of the hearing, which is expected to end today, is to collect evidence to determine the conditions and practices that lead up to the failure.

The stabilizer, which resembles a small wing on the plane's tail, controls the up and down pitch of a plane and allows pilots to maintain level flight.

Wreckage from Flight 261 showed that the threads on the jackscrew were stripped and that large sections of the rodlike assembly were not lubricated.

Since the crash, Alaska has shortened the time that the jackscrew can be used without new lubrication. That directive to Alaska and other carriers was issued by the Federal Aviation Administration.

At the time of the Flight 261 crash, The Boeing Co. was recommending end-play checks on MD-80 jackscrews every 30 months or 7,200 flight hours, whichever comes first.

In 1996, Alaska had received approval from the FAA to drop the hourly requirement. About the same time, Alaska began operating its jets more hours per day as traffic demands grew.

The jet that crashed had flown for 8,884 hours since its last jackscrew wear test.

Seattle P-I

-- Anonymous, December 16, 2000


From the GICC archives

UPDATE - FAA Working to Improve Inspection
System Flaws

Criticism after the ValuJet crash in 1996 in
the Florida Everglades was so sharp that the
FAA completely revamped its maintenance
inspection program.

But while that new program, called the Air
Transport Oversight System, has gotten good
marks for its intent, it has stumbled in
practice, congressional investigators found
last year.

The new inspection program was designed to
give federal aviation regulators a better
overall picture of an airline's operations.
Instead of inspecting individual aircraft,
government inspectors are now expected to
monitor how an airline maintains its fleet
by using sophisticated computer systems.

. . .

Nick Lacey, the FAA's director of flight
safety, said Thursday that he was ''disturbed''
that the new program had failed to adequately
keep track of issues at Alaska.

. . .

Alaska officials, who have taken numerous
steps to improve maintenance in the wake
of the FAA's actions, insist that none of the
problems has compromised safety on a flight.

GICC

-- Anonymous, December 17, 2000


But the airline's computer programming that
tracks mechanical trends did not warn the
airline until three days after the crash that
three of the MD-80 series two-engine jets
needed jackscrews replaced in 1999.

SacBee

-- Anonymous, December 17, 2000


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