McDonnell Douglas DC-10

Biman Bangladesh Airlines McDonnell Douglas DC-10

The McDonnell Douglas DC-10 is a three-engined long-range airliner, with two engines mounted on underwing pylons and a third engine at the base of the vertical stabilizer. The model was a successor to the Douglas DC-8 for long-range operations, and competed in the same markets as the Airbus A300, Boeing 747 "jumbo jet", and the physically similar Lockheed L-1011 TriStar. Some were built for the United States Air Force as air-to-air refueling tankers, designated the KC-10 Extender.

History

Ghana Airways McDonnell Douglas DC-10

The DC-10 was McDonnell Douglas's first wide-bodied commercial airliner, built to a specification from American Airlines for a widebody aircraft smaller than the Boeing 747 but capable of flying similar long-range routes. It first flew on August 29, 1970 and entered commercial service in 1971, nearly a year before the Lockheed Tristar (which was built to the same specification).

Although the DC-10's lifetime safety record is superior to that of the 747, the DC-10 suffered a trying time during the 1970s when a string of highly publicized crashes resulted in a brief grounding by the FAA.

The first problem was revealed in 1972, when American Airlines Flight 96 lost its aft cargo door after takeoff from Detroit. Unlike most other aircraft, the DC-10 was designed with cargo doors that opened outward instead of inward. This required a heavy locking mechanism to secure the door against the outward force caused by pressurization of the fuselage. On Flight 96, airport employees had forced the door shut, weakening the locking pin and causing the door to blow out as it reached altitude.

Although most carriers promptly repaired their aircraft and re-trained their ground crews, the next crash was much bloodier. Turkish Airlines Flight 981, which crashed into a forest shortly after leaving Paris' Orly Airport in 1974, killed 346 and is ranked as the fifth worst aviation disaster in history. The circumstances surrounding this crash were similar to those surrounding the previous crash: however, a modified seating configuration on the Turkish aircraft caused its control cables to be severed when the cargo door was lost, rendering the aircraft uncontrollable. Following the crash, it became common for passengers to ask not to be booked on a DC-10.

Northwest Airlines DC-10

In 1979, with the cargo door issues resolved, DC-10s around the world were grounded following the crash of American Airlines Flight 191, which killed 273 people. Flight 191 lost one of its underwing engines after taking off from O'Hare, and the engine loss damaged the aircraft's hydraulic systems, causing it to lose control. NTSB officials discovered that a maintenance procedure was culprit: American's mechanics had removed the engine and its pylon at the same time using a forklift, and the forklift operator had inadvertently cracked the pylon in the process. The procedure was not approved by Douglas, but most major airlines used it. Although Douglas was not at fault for the pylon separation, it redesigned the DC-10 to allow more redundancies in the hydraulic systems. (It is rumored, although not confirmed, that the crash was a factor in a deal several years later where AA purchased a large order of McDonnell Douglas MD-80's at a discount.)

Air New Zealand Flight 901 also went down that year near Mount Erebus in Antarctica.

Despite this troubled beginning, the DC-10 ultimately proved a reliable aircraft, much loved by engineers and pilots, and the safety record improved as the fleet hours increased. In fact, the DC-10's lifetime safety record as of 2003 surpassed that of the venerable Boeing 747.

Perhaps the most infamous instance of a DC-10 crash was the Flight 232 disaster at Sioux City in 1989. After an emergency landing with no hydraulic controls available to the crew, the aircraft was completely destroyed. The crash ironically pointed out one of the DC-10's unique safety features: it is one of the only aircraft in the world that can be flown solely by throttle, without using rudder, elevators, or ailerons. After the hydraulics failed on Flight 232, the pilots were able to crash-land the plane; over half of the passengers walked away without major injury.

The 446th and final DC-10 rolled off the production line in December 1988 and was delivered to Nigeria Airways in early 1989.

KC-10 Extender, based on the DC-10-30 airframe

Variants

The DC-10 was manufactured in five different variants:

• DC-10-10: Original version, produced from 1970. The main costumers for this domestic version were American Airlines and United Airlines. The DC-10-10 was equipped with General Electric CF6-6 engines, which was the first civil engine from the successful CF6-family.
• DC-10-15: Also known as the "DC-10 Sport," designed for use at hot high-altitude airports. The series 15 was fitted with higher-thrust General Electric CF6-50 powerplants. Only 7 were built for mexican carriers Aeroméxico and Mexicana. Produced from 1979.
• DC-10-30: The most common model, built with General Electric CF6-50 turbofan engines and larger fuel tanks to increase range and fuel efficiency. It was the second long-range model after the DC-10-40 and very popular with european flag carriers. Offered in passenger, freighter, and convertible versions. Produced from 1972.
• DC-10-40: First long-range version, fitted with Pratt & Whitney JT9D engines. It was first named DC-10-20 but renamed DC-10-40 after a request from Northwest Orient Airlines. This US-carrier and JAL were the only airlines to order the series 40. Produced from 1972.
• KC-10: Military version of the DC-10 used for aerial refueling. The aircraft was ordered by the United States Air Force and is based on the DC-10-30. Produced from 1981.

McDonnell Douglas later produced a larger variant called the MD-11. The MD-11 used newer engines, plus a glass cockpit, which eliminated the need for the flight engineer position. The MD-11 entered service in 1991. In addition, some DC-10s have been upgraded by Boeing to the so-called MD-10. The MD-10 has an upgraded cockpit giving it certain benefits of the more modern MD-11 cockpit, and more importantly, a common type rating. This allows companies such as Federal Express, which operate both the MD-10 and MD-11, to have a common pilot pool for both aircraft.

Operators

The aging model is now finding a new lease on life as a dedicated freight aircraft: many mainline carriers have sold their obsolete DC-10 fleets to cargo carriers such as FedEx. Some passenger airlines, most notably Northwest Airlines and Japan Airlines, continue to operate the DC-10 on trunk routes (although both NWA and JAL have plans to phase out their DC-10s in the near future). Almost all DC-10s remaining in passenger service are series 30 aircraft.

External Links

• Aircraft-Info.net - McDonnell Douglas DC-10 (http://www.aircraft-info.net/aircraft/jet_aircraft/mcdonnell_douglas/DC-10_MD10/)
• Airliners.net - McDonnell Douglas DC-10 & Boeing MD-10 (http://www.airliners.net/info/stats.main?id=279)
• Description at Boeing Site (http://www.boeing.com/commercial/dc-10/)

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