During the 1980s, McDonnell Douglas was the only Western manufacturer to continue development of the trijet design with an update to the DC-10, the MD-11, which initially held a range and payload advantage over its closest medium wide-body competitors which were twinjets, the in-production Boeing 767 and upcoming Airbus A330. McDonnell Douglas had planned a new trijet called the MD-XX, which were lengthened versions of the MD-11. The MD-XX Long Range aircraft would have been capable of traveling distances up to and had a wingspan of . The project was canceled in 1996, one year before McDonnell Douglas was acquired by Boeing. Boeing ended production of the MD-11 after filling remaining customer orders since the MD-11 would have competed with the 767 and 777. A study to remove the MD-11's tail-mounted engine (which would have made it a twinjet) never came to fruition as it would have been very expensive, and the MD-11 had very little in common in terms of design or type rating with other Boeing airliners. In contrast to McDonnell Douglas sticking with their existing trijet configuration, Airbus (which never produced a trijet aircraft) and Boeing worked on new widebody twinjet designs that would become the A330 and 777, respectively. The MD-11's long-range advantage was brief as it soon was threatened by the A330's four-engine derivative, the A340, and the 777. The only other notable trijet development during the 1980s was in the Soviet Union, where the Tupolev Tu-154 was re-engined with the Soloviev D-30 engine as well as a new wing design and entered serial production from 1984 as the Tu-154M.