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| + | “Ongoing metallurgical examinations of the disk will focus on detailed characterization of the inclusion and the fracture surfaces,” the NTSB said. Such a flaw could have originated in tiny impurities in the bar of metal from which the parts were made almost two decades ago, or it may have been introduced during the forging or machining processes. Metals supplied for critical aerospace use are typically melted and resolidified twice to get rid of impurities. The process is meticulously recorded so that, for every part in the engine, GE knows exactly where the metal came from and when it was produced. Likewise,cheap air jordans, every person with the smallest role in the manufacturing of any piece of the engine records and signs off on their work. “The investigators will look at all aspects of making and machining the disks,cheap jordan shoes,” said Kennedy. “There’s a whole paper trail.” Kennedy said last week that the company is “chasing down a very finite number of disks” made from the same billet of metal as the one that failed and has told airlines in a letter that only one such disk remains in an engine currently in operation. Company investigators will inspect the disk in that engine for microscopic cracks and will likely widen their inspections to more engines as the hunt for a cause continues. If any such cracks are found,cheap jordans online, the FAA will demand replacement of the disks and also review routine engine-maintenance practices to ensure such cracks are detected in future. ——— So how closely scrutinized are these engine blowouts, and how challenging will it be to find and fix the cause? In 2010, GE redesigned and retrofitted a different part inside older CF6-50 series engines, after an NTSB urgent safety recommendation that followed four serious incidents overseas involving failure of that part. For the CF6-80 engine models like the one in the Oct. 28 explosion,cheap jordan shoes, the FAA in 2009 ordered additional inspections of all critical rotating parts, including the two high-pressure turbine disks. Until the Chicago incident, there had been no uncontained failures of the CF6-80 for a decade. During that time, the NTSB reports, there were seven other uncontained engine failures in the U.S.,air jordans for cheap, mostly less serious ruptures,retro new jordans, in a variety of different engines. But one was similar in its outcome to the Chicago incident: The explosion of a GE-90 engine on a British Airways 777 jet taking off in Las Vegas in September 2015 also ignited a fearsome fire after an aborted takeoff. An engine on a London-bound British Airways jet caught fire on Sept. 8, 2015, while the plane was preparing to take off from Las Vegas, forcing passengers to escape on emergency slides. That was the first-ever uncontained failure of a GE-90 engine, and so likewise spurred a deep investigation. Yet GE’s Kennedy said that despite intense scrutiny of a widening circle of similar GE-90 engines, investigators have not been able to find a related issue in any other engine. More than a year later, the root cause of the Las Vegas blowup remains a mystery. Before the NTSB and GE investigators drilling into the Chicago incident can recommend measures to prevent a recurrence, they need to find the origin of the hidden flaw in the metal. The Las Vegas investigation shows that’s not easy. Seattle Times | Tribune News Service<ul> | ||
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