Grabbed from the headlines "
Emergency Inspections Recommended For Dreamliner Engines
NTSB Urges Action After Engine Failures in New Boeing 787, 747 Airliners (National Transportation Safety Board)
Any time I see articles about aircraft and problems, I have a special curiosity from the standpoint of a metalcaster. Quality is so paramount in the production of aircraft and airframe castings that I look to see if a casting was involved in the problem. Bad castings have caused airplanes to fall from the sky. SEE:
United Airlines Flight 232
..which 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 that was manufactured by General Electric Aircraft Engines."
"Examination of the fan disk did indeed solve the mystery. Investigators discovered an impurity and fatigue crack in the disk, and traced this defect all the way back to the initial ingot formation in 1971. Titanium when melted reacts with air which creates impurities; to prevent this, the ingot which would become the fan disk was formed using a "double vacuum" process: the raw materials were melted together in a vacuum, allowed to cool and solidify, then melted in a vacuum once more. Afterwards, the ingot was shaped into a billet, a sausage-like form about 16 inches in diameter, and tested using ultrasound to look for defects. Defects were located and the ingot was further processed to remove them. Unfortunately, some contamination remained.[1]
From what I've read regarding this current issue with the brand new Dreamliner engine is that the root cause of the failure maybe related to the coating of the engine part and not the casting itself. However, whatever metalcaster made this part had to wince when they heard about problems.
The contamination caused what is known as a hard alpha inclusion, a brittle part of the metal, which cracked during forging and then fell out during final machining. This formed a cavity with microscopic cracks at the edges. For the next 18 years, the crack grew slightly each time the engine was powered up and brought to operating temperature. Eventually the crack grew large enough to cause structural failure of the disk.[1]
Synchro ERP can help the metalcaster track the entire casting from the molding process all the way to the shipping dock with unique identifier / serial number tracking. Additionally, Synchro provides the ability to track CAR's - Corrective Action Reporting as well as a full fledged chemical and physical properties quality system.
Until next time, happy flying and see you on down the road in Nashville for the ICI!
Shane Allen
Head of Synchro ERP North American Operations
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