Aircraft Factfile and Recognition Guide - McDonnell Douglas MD-11

 

Background

The McDonnell Douglas MD-11 is a three-engined medium to long-range widebody airliner, with two engines mounted on underwing pylons and a third engine at the base of the vertical stabilizer. It is based on the DC-10, but featuring a stretched fuselage, increased wingspan with winglets, refined aerofoils on the wing and tailplane, new engines and increased use of composite materials. It features an all-digital glass cockpit that decreases the crew to two from the three required on the DC-10.

The MD-11 program was launched on December 30, 1986, with orders and commitments for 92 aircraft from 12 airlines and leasing companies. Assembly of the MD-11 began on March 9, 1988, with the first flight of an MD-11F (freighter version) on January 10, 1990. FAA certification was achieved by November 8, 1990.

The first MD-11 was delivered to Finnair on December 7, 1990. Finnair's revenue service with the MD-11 took place on December 20, 1990, when the aircraft carried passengers from Helsinki to Tenerife in the Canary Islands. First MD-11 service in the U.S. was inaugurated by Delta Air Lines, also in 1990. It was during this period that flaws in the MD-11's performance began to become apparent. It failed to meet its targets for range and fuel burn. American Airlines in particular was unimpressed, as was Singapore Airlines, who cancelled its order for 20 aircraft. The airline cited problems with the performance of the airframe and the Pratt & Whitney PW4000 engines selected for its use as reasons of the cancellation. The figures revealed exclusively to Flight International show that, based on pre-flight estimates, the P&W-powered MD-11 should have been capable of a 12,950km (7,000nm) range with a 27,680kg (61,000lb) payload. Even with the Phase 1 drag reduction in place then, the aircraft could only have achieved its full range with a 22,000kg payload, or a reduced range of 12,025km with a full payload. Although improvements were made and the aircraft did eventually perform as designed, the damage was done.

The MD-11 was one of the first commercial designs to employ a computer-assisted pitch stability augmentation system that featured a fuel ballast tank in the tailplane, and a partly computer-driven horizontal stabilizer. Updates to the software package have achieved a situation where the plane's handling characteristics in manual flight are comparable to the DC-10, despite a much greater fuel efficiency achieved by the lessened drag of the smaller tailplane.

After McDonnell Douglas merged with Boeing in 1997, the new company announced that MD-11 production would continue, as a freighter. However, in 1998 Boeing announced it would end MD-11 production after filling current orders. The last MD-11 was delivered to Lufthansa Cargo on February 22, 2001. Production ended because of lack of sales, due to internal competition from comparable aircraft, such as the Boeing 777 and external competition from the Airbus A330/A340. Also, two engines are generally less expensive to operate and maintain than three. Since there was a large demand for cargo aircraft and because there was no 777 cargo version available at the time, many airlines using the MD-11 were anxious to switch to the 777 as they had no problems selling their used MD-11s to cargo operators.  McDonnell Douglas and later Boeing performed studies on the feasibility of removing the tail engine and making it a two engine plane, but nothing came of it.

McDonnell Douglas originally projected that it would sell more than 300 MD-11 aircraft, but only a total of 200 planes were built. The MD-11 was assembled at McDonnell Douglas's Douglas Products Division in Long Beach, California (later Boeing's). In August 2006 a total of 191 MD-11 aircraft remain in airline service.

The MD-11 is a medium to long-range widebody airliner, with two engines mounted on underwing pylons and a third engine at the base of the vertical stabilizer. It is based on the DC-10, but featuring a stretched fuselage, increased wingspan with winglets, refined aerofoils on the wing and tailplane, new engines and increased use of composites.

The MD-11 features a two-crew cockpit that incorporates six interchangeable liquid-crystal-display units and advanced Honeywell VIA 2000 computers. The cockpit design is called Advanced Common Flightdeck (ACF) and is shared with the Boeing 717. Flight deck features include an Electronic Instrument System, a dual Flight Management System, a Central Fault Display System, and Global Positioning System. Category IIIb automatic landing capability for bad-weather operations and Future Air Navigation Systems are available.  The MD-11 incorporated hydraulic fuses not included in the DC-10 design, to prevent such catastrophic loss of control in event of a hydraulic failure.

A total of 200 MD-11s were manufactured in five versions: passenger (131), extended range (5), freighter (53), convertible freighter (6) and combi (5), where passengers and freight are carried on the main deck with additional freight carried below the deck.

Recognizing the MD-11

The MD-11 is a VERY easy aircraft to identify on the ground and in the air. Here's some tips to help you identify the MD-11:

Wings: Low-mounted and swept-back, with one engine hanging off each wing.  Winglets found on the tips of the wings.
Engines: Two turbofans mounted on pylons under the wings and one engine mounted on the tail.
Fuselage: Widebody fuselage based off the DC-10 but much longer.
Tail: Large tail with one engine mounted near the base of the tail. Horizontal stabilizers are swept-back, tapered, and mid-mounted on the fuselage.  Tail appears too small for the size of the aircraft.

Specifications

Sources: Wikipedia MD-11

© 2007 Steven Holzinger