Alaska Airlines Flight 261 was a scheduled international passenger flight on January 31, 2000 from Lic. Gustavo Díaz Ordaz International Airport in Puerto Vallarta, Jalisco, Mexico, to Seattle-Tacoma International Airport in Seattle, Washington, United States, with an intermediate stop at San Francisco International Airport in San Francisco, California.[1]:xii The aircraft, a McDonnell Douglas MD-83, crashed into the Pacific Ocean about 2.7 miles (4.3 km) north of Anacapa Island, California, after suffering a catastrophic loss of pitch control. The crash killed everyone aboard: two pilots, three cabin crewmembers, and 83 passengers.
The subsequent investigation by the National Transportation Safety Board determined that inadequate maintenance led to excessive wear and eventual failure of a critical flight control system during flight. The probable cause was stated to be "a loss of airplane pitch control resulting from the in-flight failure of the horizontal stabilizer trim system jackscrew assembly's acme nut threads. The thread failure was caused by excessive wear resulting from Alaska Airlines' insufficient lubrication of the jackscrew assembly".[1]:xii
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Extension of maintenance intervals
Between 1985 and 1996, Alaska Airlines progressively increased the period in between both jackscrew lubrication and end play checks with the approval of the Federal Aviation Administration (FAA).[1] Since each lubrication or end play check subsequently not conducted had represented an opportunity to adequately lubricate the jackscrew or detect excessive wear, the NTSB examined the justification of these extensions. In the case of extended lubrication intervals, the investigation could not determine what information, if any, was presented by Alaska Airlines to the FAA prior to 1996.[1] Testimony from an FAA inspector regarding an extension granted in 1996 was that Alaska Airlines submitted documentation from McDonnell Douglas as justification for their extension.[1]
End play checks were conducted during a periodic comprehensive airframe overhaul process called a C‑check. Testimony from the director of reliability and maintenance programs of Alaska Airlines was that a data analysis package based on the maintenance history of five sample aircraft was submitted to the FAA to justify the extended period between C-checks. Individual maintenance tasks (such as the end play check) were not separately considered in this extension.[1] The NTSB found that "Alaska Airlines' end play check interval extension should have been, but was not, supported by adequate technical data to demonstrate that the extension would not present a potential hazard".[1]
FAA oversight
A special inspection conducted by the NTSB in April 2000 of Alaska Airlines uncovered widespread significant deficiencies that "the FAA should have uncovered earlier".[1] The investigation concluded that "FAA surveillance of Alaska Airlines had been deficient for at least several years".[1] The NTSB noted that in July 2001, an FAA panel determined that Alaska Airlines had corrected the previously identified deficiencies. However several factors led the Board to question "the depth and effectiveness of Alaska Airlines corrective actions" and "the overall adequacy of Alaska Airlines' maintenance program".[1]
Systemic problems were identified by the investigation in the FAA's oversight of maintenance programs, including inadequate staffing, its approval process of maintenance interval extensions, and the aircraft certification requirements.[1]
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John Liotine
In 1998, an Alaska Airlines mechanic named John Liotine, who worked in the Alaska Airlines maintenance center in Oakland, California, told the Federal Aviation Administration that supervisors were approving records of maintenance that they were not allowed to approve or that indicated work had been completed when the work had not been completed. Liotine began working with federal investigators by secretly audio recording his supervisors. On December 22, 1998, federal authorities raided an Alaska Airlines property and seized its records. In August 1999 Alaska Airlines put Liotine on paid leave,[13] and in 2000 Liotine filed a libel suit against the airline. The crash of AS261 became a part of the federal investigation against Alaska Airlines because in 1997 Liotine had recommended that the jackscrew and gimbal nut of the aircraft involved in the accident be replaced.[14] In December 2001 federal prosecutors stated that they were not going to file criminal charges against Alaska Airlines. Around that time Alaska Airlines agreed to settle the libel suit by paying about $500,000; as part of the settlement, Liotine resigned.[13]
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https://en.wikipedia.org/wiki/Alaska_Airlines_Flight_261#Extension_of_maintenance_intervals
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