Cause
The investigation, while praising the actions of the flight crew for saving lives, would later attribute the cause of the accident to a failure of United Airlines maintenance processes and personnel to detect an existing fatigue crack. Post-crash analysis of the crack surfaces showed the presence of a penetrating fluorescent dye used to detect cracks during maintenance. The presence of the dye indicated that the crack was present and should have been detected at a prior inspection. The detection failure arose from poor attention to human factors in United Airlines' specification of maintenance processes.
Read more about this topic: United Airlines Flight 232