Loss of Control and Impact with Pacific Ocean Alaska ...

1 Aircraft Accident ReportLoss of Control and Impact with PacificOcean Alaska Airlines Flight 261 McDonnell Douglas MD-83, N963 ASAbout Miles North ofAnacapa Island, CaliforniaJanuary 31, 2000 national transportation safety BoardWashington, PLURIBUS UNUM NTSB/AAR-02/01PB2002-910402 Aircraft Accident ReportLoss of Control and Impact with Pacific Ocean Alaska Airlines Flight 261 McDonnell Douglas MD-83, N963 ASAbout Miles North ofAnacapa Island, CaliforniaJanuary 31, 2000 NTSB/AAR-02/01PB2002-910402 national transportation safety BoardNotation 7263E490 L Enfant Plaza, December 30, 2002 Washington, 20594E PLURIBUS UNUM national TRASPORTATION BOARDSAFETYNN ational transportation safety board . 2003. Loss of Control and Impact with Pacific Ocean , AlaskaAirlines Flight 261, McDonnell Douglas MD-83, N963AS, About Miles North of Anacapa Island,California, January 31, 2000.

2 Aircraft Accident Report NTSB/AAR-02/01. Washington, : This report explains the accident involving Alaska Airlines flight 261, a McDonnell DouglasMD-83, which crashed into the Pacific Ocean about miles north of Anacapa Island, issues discussed in this report include lubrication and inspection of the jackscrewassembly, extension of lubrication and end play check intervals, jackscrew assembly overhaulprocedures, the design and certification of the MD-80 horizontal stabilizer trim Control system, Alaska Airlines maintenance program, and Federal Aviation Administration (FAA) oversight ofAlaska Airlines. safety recommendations are addressed to the national transportation safety board is an independent Federal agency dedicated to promoting aviation, railroad, highway, marine, pipeline , and hazardous materials safety .

3 Established in 1967, the agency is mandated by Congress through the Independent safety BoardAct of 1974 to investigate transportation accidents, determine the probable causes of the accidents, issue safety recommendations, studytransportation safety issues, and evaluate the safety effectiveness of government agencies involved in transportation . The safety Boardmakes public its actions and decisions through accident reports, safety studies, special investigation reports, safety recommendations, andstatistical publications are available in their entirety on the Web at < >. Other information about available publications alsomay be obtained from the Web site or by contacting: national transportation safety BoardPublic Inquiries Section, RE-51490 L Enfant Plaza, , 20594(800) 877-6799 or (202) 314-6551 safety board publications may be purchased, by individual copy or by subscription, from the national Technical Information Service.

4 Topurchase this publication, order report number PB2002-910402 from: national Technical Information Service5285 Port Royal RoadSpringfield, Virginia 22161(800) 553-6847 or (703) 605-6000 The Independent safety board Act, as codified at 49 Section 1154(b), precludes the admission into evidence or use of board reportsrelated to an incident or accident in a civil action for damages resulting from a matter mentioned in the report. iiiAircraft Accident ReportContentsAbbreviations .. ixExecutive Summary .. xii1. Factual Information .. History of Flight .. Injuries to Persons.. Damage to Airplane .. Other Damage .. Personnel Information.. Captain .. First Officer.. Airplane Information .. Longitudinal Trim Control System Information .. Trim Control System .. Trim Control System .. Pitch Control .

5 And Certification of MD-80 Series Airplanes .. Trim Control System Certification.. Information .. Airlines MD-80 Maintenance Program .. Program Development Guidance.. Airlines Continuous Airworthiness Maintenance Program .. Airlines Reliability Analysis Program .. Assembly Lubrication Procedures .. Assembly Lubrication Intervals .. Lubrication Intervals.. Airlines Lubrication Intervals .. of Grease Type Changes .. 19, 2002, Alaska Airlines Maintenance Information Letter .. for Monitoring Acme Nut Thread Wear .. and Calculating Wear Rate.. of End Play Check Procedures .. Airlines End Play Check Procedure .. Stabilizer Restraining Fixture .. Airlines-Manufactured Restraining Fixtures .. Play Check Intervals .. End Play Check Intervals .. Airlines End Play Check Intervals.

6 Airplane s Maintenance Information .. Airplane s Last C Check Requiring an End Play Check .. 50 ContentsivAircraft Accident Personnel Statements Regarding the AccidentAirplane s Last End Play Check .. Meteorological Information .. Aids to Navigation .. Communications .. Airport Information .. Flight Recorders.. Cockpit Voice Recorder .. CVR Sound Spectrum Study .. Flight Data Recorder .. Wreckage and Impact Information .. General .. Horizontal Stabilizer Jackscrew Assembly Components.. Medical and Pathological Information .. Fire .. Survival Aspects .. Tests and Research.. Airplane Performance .. Airplane Performance Simulation Studies.. Metallurgical Examinations .. Horizontal Stabilizer Forward Spar .. Acme Screw .. Acme Screw Torque Tube.

7 Lower Mechanical Stop and Corresponding Spline Area on the Acme Screw .. Acme Nut .. Acme Nut Thread Remnant Examination .. Shear Load Capability of the Acme Nut Threads .. Studies of Thread Stress and Deformation .. Torque Tube Testing .. Additional safety board Jackscrew Assembly Examinations .. February 2000 Post-AD 2000-03-51 Jackscrew Assembly Examinations .. Examinations of Hawaiian Airlines Jackscrew Assemblies.. Examinations of Alaska Airlines Reports of Acme Screw Wobble .. Chemical and Microscopic Analyses of Grease Residues from the AccidentJackscrew Assembly .. Additional Grease Testing, Experiments, and Analysis .. Standardized Grease Testing .. Experiments and Analysis on the Surface Chemistry of AcmeNut material When Exposed to Various Greases or Grease Mixtures.

8 Wear Testing Under Various Grease Conditions.. Organizational and Management Information .. Alaska Airlines, .. Alaska Airlines Flight Crew Training .. Stabilizer Trim Check Procedures .. Runaway Stabilizer Checklist Procedures .. Stabilizer Inoperative Checklist Procedures .. Postaccident Boeing Flight Operations Bulletin on StabilizerTrim Inoperative/Malfunction Procedures .. FAA Oversight of Alaska Airlines.. General .. 93 ContentsvAircraft Accident Preaccident FAA national Aviation safety Inspection Program Inspection.. FAA Air transportation Oversight System .. Seattle CMO Memorandum on Staff Shortages for Surveillanceof Alaska Airlines .. FAA Postaccident Special Inspection of Alaska Airlines .. FAA Proposed Suspension of Alaska Airlines Heavy MaintenanceAuthority.

9 Alaska Airlines Airworthiness and Operations Action Plan .. FAA Followup Evaluation .. DOT Office of the Inspector General Report on FAA Oversightof Continuing Analysis and Surveillance Programs .. Other safety Evaluations of Alaska Airlines .. DoD Capability Survey of Alaska Airlines .. Criminal Investigation of Alaska Airlines .. Postaccident Independent safety Assessment of Alaska Airlines .. Additional Information .. Postaccident Airworthiness Directives .. safety board and FAA Correspondence Regarding the 2,000-Flight-HourEnd Play Check Interval Specified in ADs 2000-03-51 and 2000-15-15 .. safety board Statistical End Play Data Study .. Previous safety Recommendations Resulting from the Alaska AirlinesFlight 261 Investigation .. Alaska Airlines Fleetwide MD-80 Jackscrew Assembly Data and TrackingHistory.

10 MD-11 Jackscrew Assembly Acme Nut Wear History .. safety board Observations of Jackscrew Assembly Lubrications.. End Play Check Anomalies .. safety board End Play Check Observations .. Postaccident Alaska Airlines-Reported Near-Zero End Play Measurements .. Jackscrew Assembly Overhaul Information .. Jackscrew Overhaul Specifications and Authority .. Review of the Boeing DC-9 Overhaul Maintenance Manual .. safety board Maintenance Facility Observations .. Overhauled Jackscrew Assembly Data From 1996 to 1999 .. Industrywide Jackscrew Assembly Maintenance Procedures .. FAA Commercial Airplane Certification Process Study .. Fail-Safe Jackscrew Assembly Designs .. 1252. Analysis .. General .. Accident Sequence .. and Climbout .. of the Horizontal Stabilizer .. of the Jam.