For highly engineered performance products, product design along with sourcing and procurement teams are always attuned to component quality and performance trending or abnormal incidents.
Late last week, General Electric Aircraft and the National Transportation Safety Board (NTSB) issued a joint investigative update regarding an uncontrolled fiery and explosive failure of a GE CF6-80 engine that occurred on October 28 involving an American Airlines 767-300 aircraft at O’Hare International Airport in Chicago. According to an NTSB release, the aircraft right-hand engine’s stage 2 high pressure engine disk fractured into at least four pieces with the metal fractures being consistent with an “internal inclusion.” The subject disk fractured into at least four pieces, two which landed upwards of a half-mile from the aircraft.
Published reports over the weekend point to the possibility of foreign debris somehow being embedded within the special alloy that made up the specific engine disk. It is now being described as a manufacturing flaw. According to a published Bloomberg report, GE believes it has identified a “limited number” of disks manufactured at the same time that may have had the same flaw and further indicates its determination that only one other remains in operation. A letter obtained by Bloomberg notes: “We are currently working with the operator to accomplish removal of the remaining part in service.” GE indicated in a statement that the company and an unnamed supplier of the Inconel 718 alloy are now reviewing production records for NTSB investigators. GE further indicated that the engine manufacturer has not experienced such a failure for parts made with this same alloy in more than 30 years. More than 4000 of various CF6 engines are in current operating service.
While this remains an ongoing investigation, some observations clearly come to mind. First, the speed in which GE could trace the production lot origins of the alleged defective disk is a testament to the maturity of existing quality management and control processes. That will surely help in ongoing investigation and determination if other operating engine disks need to be further examined or remediated. Second, the notion that a component alloy has not demonstrated a tendency for failure in over 30 years is a reminder that for highly engineered or high performance components, manufacturers should likely continue to assume that never is never a given.
Detailed component records are mandated among aerospace and commercial aircraft supply chains because of the possibility of incidents that occurred with the Chicago incident. It serves a reminder to all other precision manufacturing supply chains that process control and traceability are necessary investments.