National Transportation Safety Board
Office of Public Affairs
National Transportation Safety Board Chairman Jim Hall today issued the following update on the Board's investigation of the crash of Alaska Airlines flight 261.
The National Transportation Safety Board's investigation of the January 31 crash of Alaska Airlines flight 261 is continuing. The Board's Maintenance Records Group has reported to the investigating team the following information. On September 29, 1997, the accident airplane (N963AS) underwent a scheduled "C-5" heavy maintenance check at the airline's facility in Oakland, California. This check was the most recent maintenance activity involving a wear tolerance check of the jackscrew and gimbal nut assembly of the plane's horizontal stabilizer.
During that check, the stabilizer jackscrew and gimbal nut underwent what is known as an "end-play check" in order to determine if the amount of wear on the assembly was within tolerances specified on Alaska Airlines' task card.
According to the maintenance record, the initial end-play measurement "has maximum allowable end play limit," and that the initial planned action was to replace the nut during the C-5 check. The record further indicates that this initial planned action was re-evaluated and the assembly was re-inspected on September 30. The maintenance record entry also indicates that the results of the re-check fell within the specified tolerances. The record further reflected that it was re-checked five times with the same result. The entry also indicates that these results were signed off by an Alaska Airlines maintenance inspector.
The Safety Board will continue its meticulous examination of the many volumes of maintenance records associated with the accident airplane, and will further investigate all maintenance activity associated with the stabilizer trim system, from date of manufacture to the date of the accident.
The significance of this information is continuing to be evaluated by the National Transportation Safety Board; no determination has been made as to whether this information has any bearing on the accident.
The accident aircraft's jackscrew/nut assembly is in our laboratory undergoing metallurgical analysis. Assemblies from two other Alaska Airlines aircraft are also being shipped to the laboratory. Assemblies from other airlines are also expected to be sent to the Board's laboratory.
On another matter, the Ventura County Medical Examiner's Office has reported to us that the remains of 46 of the 88 persons aboard flight 261 have been identified and families are being notified.
We will continue to update you with information as it becomes available.
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NTSB Office of Public Affairs: (202) 314-6100
The National Transportation Safety Board (NTSB) is an independent federal agency charged with determining the probable cause
of transportation accidents, promoting transportation safety, and assisting victims of transportation accidents and their families.