|
| |
McDonnell Douglas DC-10
JMC Air
|
McDonnell Douglas DC-10
Biman Bangladesh
|
McDonnell Douglas DC-10
Biman Bangladesh
| |
McDonnell Douglas DC-10
The McDonnell Douglas DC-10 is a three-engine, 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.
Many were built for the United States Air Force as air-to-air refueling tankers,
designated the KC-10 Extender.
History
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 comparable to that of other heavy
passenger jet aircraft, the DC-10 suffered a trying time during the 1970s when
a string of highly publicized crashes resulted in a brief grounding by the
United States Federal Aviation Administration.
Unlike many 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. In the
event that the door lock malfunctioned there was potential for catastrophic
blow-out of the whole door.
This problem was first identified in 1972, when American Airlines Flight 96
lost its aft cargo door after takeoff from Detroit. Fortunately the crew was
able to perform an emergency landing with no further incident. On Flight 96, an
airport employee had violently forced the door shut, weakening the locking pin
and causing the door to subsequently blow-out as it reached altitude. McDonnell
Douglas attempted to place the blame on the employee, who they described as
illiterate and deflected criticism of the aircraft design itself.
Although many carriers voluntarily modified the cargo doors and re-trained
their ground crews, there was no mandatory redesign of the system. Severe design
problems persisted with the aircraft's cargo doors. Indeed, two years after the
American Airlines incident an almost identical cargo door blow-out befell
Turkish Airlines Flight 981 which crashed into a forest shortly after leaving
Orly Airport in Paris. 346 people were killed in one of the worst aviation
disasters of the twentieth century. The circumstances surrounding this crash
were similar to those surrounding the previous crash, however a modified
seating configuration on the Turkish aircraft exacerbated the effects of
decompression and caused the aircraft control cables to be severed, rendering
the aircraft uncontrollable. In the aftermath of this crash all DC-10s
underwent a mandatory door redesign. The DC-10 was starting to get a reputation
as a dangerous aircraft.
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 International Airport in Chicago, USA, and the engine loss damaged the
aircraft's hydraulic systems causing it to lose control. The United States
National Transportation Safety Board officials discovered that a maintenance
procedure was the culprit. American Airlines 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.)
Also in 1979, an Air New Zealand DC-10 flew into Mount Erebus in Antarctica
during a sight-seeing trip. The Mount Erebus disaster killed all 257 on board.
This DC-10 accident was caused by complex factors not relating to the
airworthiness of the aircraft. Perhaps the most infamous instance of a DC-10
crash was the Flight 232 disaster at Sioux City, USA, 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.
Although many died, 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.
Despite its troubled beginning the DC-10 ultimately proved, and continues
to be a reliable aircraft, much loved by engineers and pilots. The aircraft's
safety record continually improved as design flaws were ironed out and fleet
hours increased. In fact, the DC-10's lifetime safety record as of 2003, is
comparable to similar second generation passenger jets.
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 Aerom?co 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 Extender: 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. Modification include having all lower cargo bays replaced with fuel
tanks. Produced from 1981. It is the longest-ranged production aircraft in
the world.
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.
This article is licensed under the GNU Free Documentation License.
It uses material from the Wikipedia article "McDonnell Douglas DC-10".
|
|
|
|
|
