A U.S. Air Force B-1B bomber returned to flight in late May of 2009 after a team led by The Boeing Company replaced its catastrophically damaged upper-center boron longeron – the aircraft's "backbone." The B-1, Swift Justice, was damaged during a routine training mission in December 2007. An engine-bleed air duct rupture triggered a temperature warning light, forcing the crew to land the aircraft at Ellsworth Air Force Base, South Dakota. Replacing the upper-center boron longeron, which is essential for stability in flight, is not a simple task because the part is unique to each aircraft, with no spares available. Boeing Integrated Defense Systems and Boeing Commercial Airplanes employees from sites across the company worked together with the Air Force and material vendors to re-create the damaged part. Specialty Materials Inc. in Lowell, Massachusetts., the original boron/epoxy supplier, provided 14,000 feet of 4-inch-wide unidirectional tape to fabricate the longeron. Cytec Engineered Materials Inc., in Tempe, Arizona, supplied the adhesive film and adhesive primer. Due to the part's complexity and 47.5-foot length, the Boeing Composite Fabrication & Assembly Center in Seattle was selected to perform the layup and cure the part in its 90-foot-deep autoclave.