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>US Flight 232

K. Calvert

Everyday we take the materials around us for granted and often never second-guess their ability. When materials fail, catastrophe is often the end result. On July 19, 1989 while United Airlines Flight 232 was in cruise at 37,000 ft en route from Denver to Chicago when it experienced a catastrophic fan rotor failure in the #2 engine. The McDonnell-Douglas Series 10 had three engines, and the #2 engine was located in the rear of the plane at the base of the vertical stabilizer. Unfortunately, all of the triple redundant hydraulic flight control systems were located in close proximity to the #2 engine. When the individual fan blade was ejected from the fan hub, it severed all three hydraulic systems seriously crippling the plane leaving it without any type of steering capability. The DC-10-10 was deprived of its rudder, horizontal stabilizer, ailerons, flaps, speed breaks, and wing slats. The flight crew were pioneers of PCA, propulsion controlled aircraft and guided the plane five miles down only using engine thrust, but lacked the capability to the slow the plane down without stalling it which resulted in the crash landing. Shocking findings stunned the world as news of the after-findings were released. The undetected metallurgical defect in the General Electric fan hub assembly sealed the planes fate ever before it even rolled off of the assembly line on March 14, 1973. Besides the metallurgical failure, there was human failure to detect the crack in the engine overhaul facility.