Originally Posted by
Pkcola
Yes, the inspection process - from Wikipedia :
The investigation, while praising the actions of the flight crew for saving lives, would later identify the cause of the accident as a failure by United Airlines maintenance processes and personnel to detect an existing fatigue crack.[1] 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.[1]
Again, stuff that never made it into the report. Yes the crack was detected by dye penetrant at GE upon initial manufacturer. The finish machining process called for shot peening of the surface, basically blasted by small BB's to compress the surface of the finished part. This would have covered over the cracked surface now rendering the imperfection invisible until the X-ray technology was implemented several years later.
So, impossible to prove, not possible to detect by the then current technology, but blamed by the NTSB.