McDonnell Douglas MD-12

The McDonnell Douglas MD-12 was a large wide-body airliner concept planned by McDonnell Douglas in the 1990s. It was first conceived as a trijet larger than the MD-11, then stretched to a quadjet airliner. It was to be similar in size to the Boeing 747, but with greater passenger capacity through two full-length passenger decks. However, the MD-12 received no orders and was canceled. McDonnell Douglas then studied larger MD-11 derivatives named MD-XX without proceeding.

Design and development

Background

McDonnell Douglas studied improved, stretched versions of the MD-11 trijet, named MD-12X with a possible lower-front passenger deck with panoramic windows. The MDC board of directors agreed in October 1991 to offer the MD-12X design to airlines. The MD-12X had a length of and a wingspan of . In November 1991, McDonnell Douglas and Taiwan Aerospace Corporation signed a Memorandum of Understanding to form a company to produce the new design. The new company would have McDonnell Douglas as the majority shareholder (51%) with Taiwan Aerospace (40%) and other Asian companies (9%) having the remaining shares.

The design grew into the much larger MD-12 with four engines and two passenger decks extending the length of the fuselage. The length of the main MD-12 variants was with a wingspan of . The fuselage was wide by high. The design was similar in concept to the Airbus A3XX and Boeing New Large Airplane, and it would have been larger than the Boeing 747 with which it would have directly competed. Douglas Aircraft also studied a smaller double-decker design in the 1960s for the aircraft that would eventually become the DC-10.

The first flight of the MD-12 was to take place in late 1995, with delivery in 1997. A new double-deck widebody has proved to be extremely expensive and complex to develop, even for the remaining aerospace giants Boeing and Airbus. The massive Airbus A380, similar in concept to the MD-12, was eventually built, but did not achieve financial success.

MD-XX

With the MD-12 program over, McDonnell Douglas focused on 300 to 400–seat MD-11 derivatives. At the 1996 Farnborough International Air Show, the company presented plans for a new trijet with high-seating and long-range named "MD-XX". The MD-XX was offered in two variants; MD-XX Stretch with a longer fuselage and MD-XX LR for longer range. Both MD-XX variant designs had wingspan, the same as MD-12. The MD-XX Stretch was lengthened over the MD-11 and had seating for 375 in a typical 3-class arrangement and 515 in all-economy seating. Its range was to be . The MD-XX LR was the same length as the MD-11, had seating for 309 in a typical 3-class arrangement and featured a range of . However, the MDC board of directors decided to end the MD-XX program in October 1996, stating the financial investment for the program was too large for the company.