Alaska Airlines announced yesterday that it will take new steps to assure the proper lubrication of jackscrews on its MD-80 jets, a week...
Alaska Airlines announced yesterday that it will take new steps to assure the proper lubrication of jackscrews on its MD-80 jets, a week after the airline discovered a jackscrew with inadequate lubrication.
Lubrication of jackscrews had been a critical maintenance item since the crash of Alaska Flight 261 in January 2000, which killed all 88 passengers and crew. The National Transportation Safety Board found that the plane’s jackscrew had not been adequately lubricated, causing the part to fail and send the plane into a dive into the Pacific Ocean off Southern California.
The company, in a posting on its Web site yesterday, said it will update its training video to show a comprehensive lubrication of a jackscrew; require digital photography each time the jackscrew is checked, to show its condition before and after the maintenance; and purchase newly developed equipment to test jackscrews for wear.
Alaska said it also will standardize the way it bolts jackscrews to aircraft to assure uniform inspections of the mechanisms, beginning with checks of all its MD-80 series planes this week.
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The jackscrew is a key component of the planes’ tail section, with no backup system. It is a 2-foot-long, 1 ½-inch-diameter threaded shaft that moves up and down through a stationary gimbal nut, raising and lowering the leading edge of the stabilizer, the winglike structure on the tail that helps the plane climb and descend.
The airline’s procedures for inspecting its jackscrews came under scrutiny when The Seattle Times reported Sept. 29 that three Alaska mechanics reported they had found a jackscrew with inadequate lubrication during an overnight inspection in Seattle on Jan. 10.
Alaska disputed the mechanics’ reports, saying it had no evidence to support their claims. But the airline ordered inspections of all 26 of its MD-80s, finding one last week with no grease in the middle but some lubrication at the ends. The inspections were completed over the weekend, with no additional problems.
The last prior inspections of the jackscrews found Wednesday and in January were certified at AAR Aircraft Services in Oklahoma City, one of three contract repair stations that perform major repair work for Alaska.
Alaska is legally required to oversee the work at the repair stations under federal regulations, and has its own inspectors at the facilities.
Other jackscrew inspections are conducted by Alaska mechanics between flights.
The Federal Aviation Administration, responding to questions about the January incident, opened an investigation into that incident, as well as a second report of a problem jackscrew three weeks ago.
In both of those cases, no excessive wear of the jackscrews was found and no planes were flown in an unsafe condition, Alaska said.
In its Web posting, Alaska said Boeing (which merged in 1997 with McDonnell Douglas, the maker of MD-80s) and Smiths Aerospace, the jackscrews’ manufacturer, reviewed Alaska’s lubrication procedures for jackscrews. That review found that Alaska is following FAA requirements for maintaining jackscrews.
But Fred Mohr, Alaska’s vice president of maintenance and engineering, said in the Web posting that the new steps are being added “to provide an even higher level of precision and scrutiny.”
Steve Miletich: 206-464-3302