McDonnell Douglas MD-11
The McDonnell Douglas MD-11 is an American trijet wide-body airliner which was manufactured by McDonnell Douglas and later by Boeing. The MD-11 is the largest trijet ever built.
Following DC-10 development studies, the MD-11 program was launched on December 30, 1986. Assembly of the first prototype began on March 9, 1988. Its maiden flight occurred on January 10, 1990, and it achieved Federal Aviation Administration certification on November 8. The first delivery was to Finnair on December 7 and it entered service on December 20, 1990.
It retains the basic trijet configuration of the DC-10 with updated General Electric CF6-80C2 or Pratt & Whitney PW4000 turbofan engines. Its wingspan is slightly larger than the DC-10 and it has winglets. Its maximum takeoff weight is increased by % to. Its fuselage is stretched by % to to accommodate 298 passengers in three classes over a range of up to. It features a glass cockpit that eliminates the need for a flight engineer.
Originally positioned as a longer-range alternative to rival twinjets, the existing Boeing 767 and the upcoming Boeing 777 and Airbus A330, the MD-11 initially failed to meet its range and fuel burn targets, which impacted its sales despite a performance improvement program. McDonnell Douglas's financial struggles prevented further development of the MD-11 before it was acquired by Boeing in 1997; the unified company decided to terminate the MD-11 program after filling outstanding orders due to internal competition from Boeing's own 767 and 777. Only 200 units were built, of which roughly a quarter were freight aircraft, and production concluded in October 2000. In November 2014, it was officially retired from passenger service, last flown by KLM. Many of the MD-11 passenger fleet were converted to freighter specification, with many remaining in service as of 2025.
On November 8, 2025, days after a deadly crash in Louisville, Kentucky, the FAA issued an Emergency Airworthiness Directive grounding all MD-11 aircraft. The planes cannot fly again until they are inspected and any necessary repairs are completed. The FAA said the directive was issued because the same safety issue could affect other aircraft of the same design. As of November 2025, the National Transportation Safety Board was investigating the crash.
Development
Origins
Although the MD-11 program was launched in 1986, McDonnell Douglas had started to search for a DC-10 derivative as early as 1976. Two versions were considered then: a DC-10-10 with a fuselage stretch of and a DC-10-30 stretched by. The latter version would have been capable of transporting up to 340 passengers in a multi-class configuration, or 277 passengers and their luggage over. At the same time, the manufacturer was seeking to reduce wing and engine drag on the trijet. Another version of the aircraft was also envisaged, the "DC-10 global", aimed to counter the risks of loss of orders for the DC-10-30 that the Boeing 747SP and its range were causing. The DC-10 global would have incorporated more fuel tanks.While continuing their research for a new aircraft, McDonnell Douglas designated the program DC-10 Super 60, previously known for a short time as DC-10 Super 50. The Super 60 was to be an intercontinental aircraft incorporating many aerodynamic improvements in the wings, and a fuselage lengthened by to allow for up to 350 passengers to be seated in a mixed-class layout, compared to 275 in the same configuration of the DC-10.
Following more refinements, in 1979 the DC-10 Super 60 was proposed in three distinct versions like the DC-8. The DC-10-61 was designed to be a high-capacity medium-range aircraft. It would have a fuselage stretch of over the earlier DC-10 models, enabling it to carry 390 passengers in a mixed class or 550 passengers in an all-economy layout, similar to Boeing's later 777-300 and Airbus A340-600. Like the DC-8, the series 62 was proposed for long-range routes. It would feature a more modest fuselage stretch of, along with an increased wingspan and fuel capacity. It would be capable of carrying up to 350 passengers or 440 passengers, similar to the later Boeing 777-200 or the Airbus A330-300/A340-300/500. Finally, the series 63 would have incorporated the same fuselage as the DC-10-61 as well as the larger wing of the -62. After high-profile accidents in the 1970s, such as Turkish Airlines Flight 981 and American Airlines Flight 191, the trijet's reputation was seriously damaged by doubts regarding its structural integrity. For these reasons, and due to a downturn in the airline industry, all work on the Super 60 was stopped.
In August 1981, a Continental Airlines DC-10-10 was leased to conduct more research, particularly on the effects the newly designed winglets would have on aircraft performance. Different types of winglets were tested during that time in conjunction with NASA at the McDonnell Douglas flight test facility in Yuma, Arizona and Edwards Air Force Base. McDonnell Douglas was again planning new DC-10 versions that could incorporate winglets and more efficient engines developed at the time by Pratt & Whitney and Rolls-Royce. The manufacturer finally rationalized all these studies under the MD-EEE designation, which was later modified to the MD-100 following some more changes. The MD-100 was proposed in two versions: the Series 10, having an airframe shorter by compared to the DC-10 and seating up to 270 passengers in a mixed-class configuration; and the Series 20, incorporating a fuselage stretch of over the DC-10 and able to seat up to 333 passengers in the same kind of configuration as the Series 10. Both versions could be powered by the same engine families as the actual MD-11 plus the RB.211-600. However, the situation for the manufacturer, and the airline industry in general, did not look bright. No new DC-10 orders were received, and many observers and customers doubted that the manufacturer would stay in business much longer. Thus, the board of directors decided in November 1983 to once again cease all work on the projected new trijet.
The following year no new orders for the DC-10 were received. The production line was kept active thanks to earlier orders from the United States Air Force for 60 KC-10A tankers. McDonnell Douglas was still convinced that a new derivative for the DC-10 was needed, as shown by the second-hand market for their Series 30 and the heavier DC-10-30ER version. Thus, in 1984 a new derivative aircraft version of the DC-10 was designated MD-11. From the very beginning, the MD-11X was conceived in two different versions. The MD-11X-10, based on a DC-10-30 airframe, offered a range of with passengers. That first version would have had a maximum takeoff weight of and would have used CF6-80C2 or PW4000 engines. The MD-11X-20 was to have a longer fuselage, accommodating up to 331 passengers in a mixed-class layout, and a range of.
As more orders for the DC-10 were received, McDonnell Douglas used the time gained before the end of DC-10 production to consult with potential customers and to refine the proposed new trijet. In July 1985, the board of directors authorized the Long Beach plant to offer the MD-11 to potential customers. At the time, the aircraft was still proposed in two versions, both with the same fuselage length, a stretch of over the DC-10 airframe, as well as the same engine choice as the MD-11X. One version would have a range of with a gross weight of and transport up to 337 passengers, while the second would carry 331 passengers over. A year later, as several airlines had committed to the MD-11, the situation was looking optimistic. The aircraft was now a 320-seater baseline and defined as an stretch over the DC-10-30 powered by the new advanced turbofans offered by the major engine manufacturers giving it a range of. Other versions, such as a shortened ER with a range of, an all-cargo offering a maximum payload of, and a Combi with a provision for ten freight pallets on the main deck, were proposed. Further growth of the aircraft was also foreseen, such as the MD-11 Advanced.
The limited innovation in the MD-11's design has been attributed to McDonnell Douglas's declining cash flow, as the company faced problems with military contracts and reduced demand for its commercial aircraft. With constrained financial resources, the MD-11 was developed as an updated version of the DC-10 rather than an all-new design. During the same period, competitors Airbus and Boeing launched clean-sheet aircraft that became the Airbus A330/A340 and Boeing 777. As a trijet, the MD-11 was less fuel-efficient, but McDonnell Douglas promoted it as offering greater range than contemporary twinjet widebodies such as the Boeing 767 and the forthcoming Airbus A330 and Boeing 777. Aerospace consultant Scott Hamilton described the MD-11 in 2014 as "classically ill-timed", noting that it entered service "at the end of the three- or four-engine era, just ahead of the real move to ETOPS with the 777", and that it was produced by "a dying company that no longer could meet promises." At the time of its introduction, sales were hampered by doubts about McDonnell Douglas's long-term viability." The company's strategy to "outsource everything but design, final assembly, and flight testing and sales of the MD-11" was also cited as a factor contributing to the decline of its commercial aircraft business.
Launch and costs
On December 30, 1986, McDonnell Douglas launched the MD-11 with commitments for 52 firm orders and 40 options in three different versions from ten airlines and two leasing companies. Orders from Dragonair, Scandinavian, and UTA, an undisclosed customer, were canceled by 1988.In 1987, the program was to cost $1.5 billion with $500 million for development and almost $1 billion for tooling and inventory. The first 52 firm orders totaled $5 billion, or $95 million each, while the A340 sold for $67 million. At certification in 1990, $2.5 billion were invested in initial production inventory, and $700 million for engineering, tools, and flight testing. While it was selling for $100 million, the initial MD-11 jets cost $120 to $150 million to produce but this was to reduce to $90 million with manufacturing experience over the program life for an 11% gross profit margin, less than the 15% to 20% Boeing obtains.
In 1992, the $1.7 billion development cost was to be spread over the first 301 aircraft produced for $100 million each. In 1995, because costs and revenues could not be reasonably estimated over the program life, McDonnell Douglas took a pre-tax charge of $1.838 billion for deferred production costs and for reduced support and tooling value. In 1999, the unit cost was $132-$147.5 million.