Accident Board Findings

The NTSB determined that the probable cause of this accident was the inadequate consideration of the human factors limitations in the inspection and quality control procedures used by the UAL engine overhaul facility. These limitations resulted in the failure to detect a fatigue crack originating from a previously undetected metallurgical defect located in a critical area of the stage 1 fan disk of the engine.

The NTSB also determined that the catastrophic disintegration of the fan disk resulted in the liberation of engine debris in a pattern of distribution and with energy levels that exceeded the level of protection provided by design features of the hydraulic systems that operate the flight controls of the DC-10.

The NTSB identified 21 findings for this accident. The findings are excerpted from the report, and available at the following link: NTSB Findings

The entire NTSB report (NTSB/AAR-90-06) can be viewed at the following link: NTSB Report

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