The company refutes the suggestion that the incidents reflect unsafe maintenance practices but has nevertheless announced new policies designed to ensure the assemblies receive the lubrication needed to protect them from premature wear.

The components receiving all of the attention are jackscrew assemblies built into the tail section of MD-80 series jets manufactured by Boeing and the former McDonnell Douglas. The mechanisms help control the vertical pitch of the planes in flight, by rotating the two-foot jackscrew through a stationary gimbal nut to raise and lower the leading edge of the rear wing stabilizer.

The jackscrew is supposed to be lubricated with grease to help it withstand the stress encountered during flight. Federal investigators found that insufficient lubrication caused excessive wear and eventually the failure of a jackscrew on Flight 261, an MD-83 that dove into the Pacific off Los Angeles in January 2000. That crash killed all passengers and crew members and led regulators to declare jackscrew lubrication a critical maintenance item.

Alaska Airlines, which is based in Seattle, claimed to have strengthened its procedures for maintaining jackscrew assemblies, which have no backup safeguards.But mechanics performing maintenance on an MD-83 at a company facility on Jan. 10 saidthe screw and the gimbal nut showed no sign of the grease that should have been present. The Seattle Times, which first reported the incident in its Sept. 29 issue, quoted the mechanics reports as saying they found black residue on the screw instead.

Based on their findings they speculated that the assembly was not greased during its previous maintenance interval, performed Nov. 3 by a subcontractor, AAR Aircraft Services, of Oklahoma City. According to news reports, Alaska Airlines and AAR insisted the Nov. 3 procedures were properly executed.

In response to the Times Sept.29 report, the FAA opened an inquiry that is still ongoing. Alaska Air then announced Sept. 30 that it would inspect the jackscrew assemblies on all 26 of its MD-80 series jets. On Oct. 9, the company reported the results. Assemblies on 25 of the planes were found to have adequate lubrication. The 26^th was not, as the jackscrew had grease at either end but was dry in its middle section.

Two days later, the airline announced new measures to ensure the assemblies get adequately lubricated. Weve conducted discussions with Boeing and Smiths Aerospace [manufacturer of the jackscrews] and confirmed that our existing jackscrew maintenance processes meet the requirements in the FAAs airworthiness directive, Vice President of Maintenance and Engineering Fred Mohr said. Because we are committed to having the best possible maintenance processes relating to jackscrews, additional elements are being incorporated to provide an even higher level of precision and scrutiny.

The company said it will update a video showing mechanics how to grease the assembly and require photos before and after each occasion on which the assembly is greased. It said it will also buy new equipment to gauge jackscrews for wear.

In public statements, management for Alaska Airlines has focused on the fact that the inadequately greased assemblies were discovered and addressed,rather than the idea of them being airborne with insufficient lubrication.

In each case, the precautions taken underscore the effectiveness of our maintenance program andinspection procedures in ensuring the safety of our aircraft, Mohr said.Officials noted that the jackscrews in both cases were checked and found to be within prescribed wear limits. The screw from the January inspection was left in service while the one discovered this month was replaced.

The Seattle Times reported that Alaska Airlines disputed the findings of the mechanics who conducted the Jan. 10 inspection, but the carrier declined comment when questioned by Lube Report.

Neither did the airlinecomment directly about its credibility on such issues. Twice this year the company has been fined byadministrative law judges withthe U.S. Department of Labor, whofound it violated whistleblower protections in its treatment of maintenance personnel.

According to the Times, in one case, the company fired a maintenance facility supervisor after he complained that management was pressuring staff to return planes with maintenance needs to service too quickly. In the other case, the Times said, a senior mechanic was suspended after raising concerns with the FAA about a proposed reorganization of Alaska Airlines maintenance operations. The airline confirmed therulings against it but said it is appealing both decisions.

Also this year, the Times reported, the company reached an out-of-court settlement with a maintenance supervisor who filed a lawsuit alleging the company wrongfully fired him for complaining it had failed to complete a tool-inspection program ordered by the FAA after the crash of Flight 261. Before settlement the company contended the employee was fired for not being a good supervisor.

Alaska Airlines argued that it has a comprehensive program encouraging employees to report safety concerns without fear of reprisal. Part of the program allows employees to make anonymous reports, while another guarantees immunity to those who are identified. Reports are investigated by a board with representatives from the company, the union representing its mechanics and a pilots association.