Design engineers are probably smiling this morning at the Alcoa Technical Center outside of Pittsburgh, Pa. Mitsubishi Aircraft Corp., part of Mitsubishi Heavy Industries, announced last night that it is dropping plans to use a composite carbon fiber wing box for its new regional jet, and will go instead with aluminum. The first flight of the 92-seat MRJ90 will be delayed by as much as six months because of major design changes to the cabin and the wing box.
The announcement follows the stunning news that a Mitsubishi-built composite wing for the Dreamliner 787 broke in a stress test. Mitsubishi is one of the major sub contractors chosen by Boeing to design and manufacture major sections fo the Dreamliner. For Mitsubishi it was an opportunity to learn more about leading-edge aircraft design and manufacturing as it broke into the regional jet market, competing against Embraer and Bombardier.
Its regional jet had been the most ambitious new design to use composites in smaller aircraft. Mitsubishi now says only about 15 percent of the structure will be made from composites. In other words, Mitsubishi designers will be using composites in areas, such as the tail, where they have been used for more than 25 years.
Wing failure wasn’t the only major design problem that Mitsubishi encountered with composites. The design for the Dreamlimer was also significantly above projected weight.
Scott Carson, Boeing’s ahead of commercial airlines, did not disclose the wing test problems for a month, and he recently was replaced by Boeing in the face of growing schedule problems for the troubled aircraft.