McDonnell Douglas MD-11

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 40 feet (12 m) and a DC-10-30 stretched by 30 feet (9.1 m). 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 5,300 nautical miles (9,800 km). 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.[4]

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 26 feet 8 inches (8.13 m) 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.[4]

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 40 feet (12 m) 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 26 ft 7 in (8.10 m), along with an increased wingspan and fuel capacity. It would be capable of carrying up to 350 passengers (mixed class) or 440 passengers (all-economy), 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.[4]

Nine-abreast economy class

In 1981, a Continental Airlines DC-10-10 (registration number N68048) was leased to conduct more research, particularly the effects the newly designed winglets would have on aircraft performance. Different types of winglets were tested during that time in conjunction with NASA. McDonnell Douglas was again planning new DC-10 versions that could incorporate winglets and more efficient engines developed at the time by Pratt & Whitney (PW2037) and Rolls-Royce (RB.211-535F4). The manufacturer finally rationalized all these studies under the MD-EEE (Ecology-Economy-Efficiency) designation, that 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 6 ft 6 in (1.98 m) 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 20 ft 6 in (6.25 m) 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 among the 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.[4]

The following year no new orders for the DC-10 were received. The production line was kept active thanks to earlier orders from the U.S. 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 6,500 nautical miles (12,000 km) with passengers. That first version would have had a maximum takeoff weight (MTOW) of 580,000 pounds (260,000 kg) 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 6,000 nautical miles (11,000 km).[4]

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 22 ft 3 in (6.78 m) over the DC-10 airframe, as well as the same engine choice as the MD-11X. One version would have a range of 4,780 nautical miles (8,850 km) with a gross weight of 500,000 pounds (230,000 kg) and transport up to 337 passengers, while the second would carry 331 passengers over 6,900 nautical miles (12,800 km). 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 18 ft 7 in (5.66 m) stretch over the DC-10-30 powered by the new advanced turbofans offered by the major engine manufacturers and giving it a range of 6,800 nautical miles (12,600 km). Other versions, such as a shortened ER with a range of 7,500 nautical miles (13,900 km), an all-cargo offering a maximum payload of 200,970 pounds (91,160 kg) 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.[4]

The MD-11 has a center engine at the base of the vertical stabilizer, like the DC-10. Additionally, the nacelle has a bulge at the front, similar to the DC-10-40 variant.

The lack of innovation from McDonnell Douglas during the MD-11's design had been attributed to the company's declining cash flow, as it struggled with problems with its military contracts and declining orders for its commercial jets.[5] Limited company resources resulting in the MD-11 being developed as a refinement of the existing DC-10, in contrast to rivals Airbus and Boeing who during this time period developed all-new aircraft designs that would become the Airbus A330/A340 and Boeing 777. As a trijet the MD-11 was less fuel-efficient but had a greater range than its mid-size widebody contemporaries which were twinjets (the existing Boeing 767 and upcoming Airbus A330).[6] Aerospace consultant Scott Hamilton, in a 2014 article, said that the MD-11 was "classically ill-timed" as "it came at the end of the three- or four-engine era, just ahead of the real move to ETOPS with the 777".[7] McDonnell Douglas's initiative to "outsource everything but design, final assembly, and flight testing and sales of the MD-11" was also seen as contributing to the end of their commercial airline business.[8]

On December 30, 1986, McDonnell Douglas launched the MD-11 with commitments for 52 firm orders and 40 options[9] in three different versions (passenger, combi and freighter) from ten airlines (Alitalia, British Caledonian, Dragonair, Federal Express, Finnair, Korean Air, Scandinavian Airlines, Swissair, Thai Airways International, and VARIG)[9] and two leasing companies (Guinness Peat Aviation and Mitsui).[9] Orders from Dragonair, Scandinavian and UTA,[9] 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 totalled $5 billion, or $95 million each, while the A340 sold for $67 million.[10] 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.[11]

In 1992, the $1.7 billion development cost was to be spread over the first 301 aircraft produced for $100 million each.[12] In 1995, because costs and revenues could not be reasonably estimated over the program life, MDC took a pre-tax charge of $1.838 billion (~$3.03 billion in 2021) for deferred production costs and for reduced support and tooling value.[13] In 1999, unit cost was $132-$147.5 million[13] (equivalent to $205-$228.8 million in 2021 dollars)[14].

The first MD-11 was delivered to Finnair on December 7, 1990 and made its first revenue on December 20, 1990.

Assembly of the first MD-11 began on March 9, 1988, and the mating of the fuselage with wings occurred in October that year. The first flight was originally planned to occur in March 1989, but numerous problems with the manufacturing, delays with suppliers producing essential components and labor industrial actions delayed the ceremonial roll out of the prototype until September of that year. The following months were used to prepare the prototype for its maiden flight, which finally happened on January 10, 1990. The first two aircraft manufactured were intended for FedEx and thus, were already fitted with the forward side cargo door. They remained with the manufacturer as test aircraft until 1991 before being completely converted to freighters and delivered to their customer. FAA certification was achieved on November 8, 1990 while the European Joint Aviation Authorities (JAA) certified the MD-11 on October 17, 1991 after approximately 200 separate issues were resolved.[4] Fuselage sections for the DC-10, KC-10, and MD-11 were built by General Dynamics' Convair Division.[15] Yugoslav Airlines, already flying several DC-10s, became the first customer of the MD-11. Three aircraft were manufactured but were never delivered due to the Yugoslav Wars. The first MD-11 was delivered to Finnair on December 7, 1990 and it accomplished the first revenue service by an MD-11 on December 20, 1990, carrying passengers from Helsinki to Tenerife in the Canary Islands. MD-11 service in the U.S. was inaugurated by Delta Air Lines the following year.

It was during this period that flaws in the MD-11's performance became apparent. It failed to meet its targets for range and fuel burn.[16] American Airlines in particular was unimpressed with the 19 MD-11s that it received, as was Singapore Airlines who canceled their order for 20 MD-11s and instead ordered 20 Airbus A340-300s. American Airlines cited problems with the performance of the engines and airframe, while Singapore Airlines stated that the MD-11 could not operate on the airline's long haul routes.[17] Pre-flight estimates indicated that the P&W-powered MD-11 was to have a 7,000 nautical miles (13,000 km) range with 61,000 pounds (28,000 kg) of payload. With the Phase 1 drag reduction in place then, the aircraft could only achieve its full range with 48,500 pounds (22,000 kg) of payload, or a reduced range of 6,493 nautical miles (12,025 km) with a full payload.[18]

In 1990, McDonnell Douglas, along with Pratt & Whitney and General Electric began a modification program known as the Performance Improvement Program (PIP) to improve the aircraft's weight, fuel capacity, engine performance and aerodynamics. McDonnell Douglas worked with NASA's Langley Research Center to study aerodynamic improvements.[19] The PIP lasted until 1995 and recovered the range for the aircraft. However, by this point sales of the MD-11 had already been significantly impacted.[16] In 1995, American Airlines sold their 19 MD-11s to FedEx, as the PIP program was not sufficient for the aircraft to fly the DFW-Hong Kong route.[7]

After McDonnell Douglas merged with Boeing in 1997, the unified company decided that MD-11 production would continue exclusively with the freighter variant. In 1998, Boeing announced it would end MD-11 production after filling orders on hand.[20] The last passenger MD-11 built was delivered to Sabena in April 1998.[21] Assembly of the last two MD-11s were completed in August and October 2000; they were delivered to Lufthansa Cargo on February 22 and January 25, 2001 respectively.[3] Production ended because of lack of sales, resulting from internal competition from the Boeing 767-400 and Boeing 777, as well as external competition from the Airbus A330/A340.

The MD-11 was assembled at McDonnell Douglas's Douglas Products Division in Long Beach, California (later Boeing's facility). McDonnell Douglas originally projected that it would sell more than 300 MD-11 aircraft, but only 200 were built.

After McDonnell Douglas did the KDC-10 conversion for the Royal Netherlands Air Force in 1992, they proposed a tanker/transport version of the MD-11CF which had the in-house designation KMD-11. McDD offered either conversion of second hand aircraft (KMD-11) or new build aircraft (KC-10B), the proposed KMD-11 offered 35,000 lbs more cargo capacity and 8,400 lbs more transferable fuel than the KC-10A. It was offered to the RNAF and RSAF in the 1990s and the RAAF in the early 2000s.[28]

In 1993, 1995 and again in 1996, McDonnell Douglas performed studies on the feasibility of a twin-engine jet using MD-11 components, but nothing came of any of them.[29][30][31] In August 1997, just after the merger with Boeing, a presentation was made pitching an MD-11 twin with a new Boeing wing to fill the gap between the 767 and the 777, but again the proposal came to nothing.[31]

After ending the MD-12 program, McDonnell Douglas focused on 300–400-seat MD-11 derivatives. At the 1996 Farnborough International Air Show, the company presented plans for a new tri-jet with high seating and long range named "MD-XX".[32] It was offered in the MD-XX Stretch and MD-XX LR versions. The MD-XX Stretch version was to have a longer fuselage than the MD-11 and seat 375 in a typical three-class arrangement. The MD-XX LR was to have a longer range and be the same length as the MD-11; it was to have typical three-class seating for 309. However, the MDC board of directors decided to end the MD-XX program in October 1996, because the financial investment was too large for the company.[33]

• On April 6, 1993, China Eastern Airlines Flight 583, an MD-11 went into severe oscillations when a crew member accidentally deployed the slats during cruise flight over the Pacific Ocean near the Aleutian Islands. Two passengers were seriously injured and later died.[48][49]
• On July 31, 1997, FedEx Express Flight 14, MD-11 N611FE, crashed during a landing at Newark Liberty International Airport, New Jersey. The aircraft flipped onto its back and subsequently burned, following a landing attempt from an unstabilized flare. The five occupants survived with injuries.[50]
• On September 2, 1998, Swissair Flight 111, MD-11 HB-IWF, crashed into the Atlantic Ocean near Halifax, Nova Scotia while en route from New York City to Geneva, Switzerland. All 229 people on board perished. The cause of the crash was determined to have been a fire caused by improper wiring of passenger entertainment system units added by Swissair. The fire started at the front of the aircraft and quickly grew uncontrollable, attributed partly to the poor flame retardant properties of its metalized mylar insulation.[51]
• On April 15, 1999, Korean Air Cargo Flight 6316, MD-11 registration number HL7373, crashed shortly after takeoff while operating cargo flight KE6316 from Shanghai Hongqiao International Airport to Seoul. After takeoff, the flight was cleared to climb to 4,900 feet (1,500 meters). The aircraft climbed to 4,500 ft (1,400 m). Due to confusion on the flight deck, the captain thought the aircraft was too high and needed to descend. The captain pushed the control column abruptly forward, causing the MD-11 to enter a rapid descent from which it could not be recovered. All three occupants on board and five people on the ground were killed.[52]
• On August 22, 1999, China Airlines Flight 642, an MD-11 operated by subsidiary Mandarin Airlines, crashed while landing at Hong Kong International Airport during typhoon Sam that exceeded its crosswind specifications, also flipping onto its back and burning. Three passengers were killed.
• On October 17, 1999, FedEx Express Flight 87, MD-11 N581FE, was written off after landing at Subic Bay International Airport, Philippines. The aircraft was operating from Shanghai Hongqiao International Airport. Upon landing, the aircraft rolled down the whole length of the runway before plunging into the bay where it was completely submerged except for the cockpit. An excessive approach and landing speed was pointed out as probable cause of the accident.[53]
• On March 23, 2009, FedEx Express Flight 80, MD-11F N526FE, crashed at Narita International Airport, Japan while landing in windy conditions. Airport surveillance video showed the aircraft becoming airborne again after the first touchdown, then impacting nose-first the second time and turning onto its left side, erupting into flames; the impact flipped the aircraft upside-down. The aircraft finally came to rest some distance left of the runway. The two flight crew members were killed.[54][55]
• On November 28, 2009, Avient Aviation Flight 324, MD-11F Z-BAV (c/n 48408), crashed on takeoff from Shanghai Pudong International Airport on a flight to Bishkek-Manas International Airport, Kyrgyzstan with the loss of three lives.[56] The aircraft was written off.[57]
• On July 27, 2010, Lufthansa Cargo Flight 8460, a MD-11F, crash-landed at King Khalid International Airport in Riyadh, Saudi Arabia. The captain and first officer evacuated the aircraft with injuries. This incident is very similar to FedEx Flight 80 and FedEx Flight 14.[58]
• On February 13, 2016, Western Global Airlines Flight 4425 was involved in a stowaway incident that was discovered when the plane had stopped in Harare Airport, Zimbabwe for a fuel stop en-route to King Shaka International Airport, South Africa from Munich, Germany. The deceased stowaway was located in the plane’s cargo hold after ground staff at Harare noticed blood dripping from one of the MD-11’s cargo doors. The crew initially stated that they believed the blood to have come from a bird strike which had been noticed by ground staff at Munich Airport earlier in the plane's journey, but a body of a man who had stowed away on the flight was discovered shortly after the plane and its crew were seized by Zimbabwean authorities.[59][60][61]
• On June 6, 2016, UPS Airlines Flight 61, MD-11F N277UP suffered a runway excursion and nose gear collapse in a takeoff accident at Seoul-Incheon International Airport (ICN). Takeoff from runway 33L was aborted and the aircraft continued past the end of the runway. The nose gear collapsed and the nos. 1 and 3 engines contacted the grass. The flight was bound for Ted Stevens Anchorage International Airport. All 4 crew members survived without injury. The aircraft was written off.[62]

The MD-11 had problems with its flight control systems that have resulted in multiple accidents and incidents since the aircraft's introduction.[63] The initial design of the slat/flap lever in the cockpit left it prone to being accidentally dislodged by crew in flight. The defect has been corrected since 1992.[64] In the early 2000s, Boeing improved the flight control software at the urging of the FAA to reduce the possibility of violent unintentional pitch movements.[63]

In an effort to improve fuel efficiency, McDonnell Douglas designed the MD-11's center of gravity to be much farther aft than that of other commercial aircraft. There was also a fuel-ballast tank in the MD-11's horizontal stabilizer since its tailplane was smaller than the DC-10's to improve fuel efficiency, but this was found to inhibit the MD-11's crosswind performance.[6] These design features, coupled with standard landing speeds 20–30 knots (35–55 km/h) faster than those of comparable aircraft, significantly reduce the MD-11's margin for error during the takeoff and landing phases, making it more difficult to handle than the smaller DC-10.[7][65] A number of operators have introduced special training to assist crews in safely handling the MD-11's critical phases of flight.[58]