McDonnell Douglas DC-10 Totally Explained

Everything about Mcdonnell Douglas Dc-10 totally explained

The McDonnell Douglas DC-10 is an American three-engine medium- to long-range widebody 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 company's DC-8 for long-range operations, and competed in the same markets as the Airbus A300, Boeing 747, and Lockheed L-1011 Tristar, which has a similar layout to the DC-10.
Production of the DC-10 ended in December 1988 with 386 delivered to airlines and 60 to the U.S. Air Force as air-to-air refueling tankers, designated the KC-10 Extender. The DC-10 was succeeded by the related McDonnell Douglas MD-11 which entered service in 1990.

Development

The design of the DC-10 began in 1967. It became McDonnell Douglas's first commercial airliner after the merger between McDonnell Aircraft Corporation and Douglas Aircraft Company in 1967. It was built to a specification from American Airlines for a widebody aircraft smaller than the Boeing 747 but capable of flying similar long-range routes from airports with shorter runways. Although the Boeing 747 had commercial advantages due to its size, smaller airports couldn't accommodate it because of gate restrictions and runway length. McDonnell Douglas was able to capitalize on this with the DC-10.
   The DC-10 first flew on August 29 1970 and entered commercial service with launch customer American Airlines on August 5 1971 on a round trip flight between Los Angeles and Chicago, nearly a year before the Lockheed L-1011 Tristar (which was built to a similar specification). The similarity to the L-1011 in terms of passenger capacity and launch in the same time frame resulted in a head to head sales competition which affected profitability of the aircraft. The launch customers for the DC-10 were American Airlines and United Airlines with orders for 25 and 60 respectively of the Series 10 model. Eventually, the DC-10 was able to distinguish itself from its competitors with a second engine supplier, which has the possible effect of controlling costs due to competition, as well as earlier introduction of longer range variants than the L-1011.
   The first DC-10 version was the "domestic" series 10 with a range of 3,800 miles (6,112 km). The series 20 (only ordered by Northwest Orient and Japan Airlines) had a typical load range of 5,750 mi (9,265 km) or a maximum payload range of 7,520 km. The series 30 had a typical load range of 6,220 mi (10,010 km) or a maximum payload range of 7,410 km. The series 20 was powered by Pratt & Whitney JT9D engines, whereas the series 10 and 30 engines were General Electric CF6.
   Before delivery of its aircraft, Northwest's president asked that the "series 20" aircraft be redesignated "series 40" because he argued that the aircraft was much improved over the original design. The FAA issued the Series 40 certificate on 27 October 1972.
   One of the main visible differences between the models is that the series 10 has three sets of landing gear (one front and two main) while the series 30 and 40 have four gear (one front, three main). The center main 2-wheel landing gear (which extends from the center of the fuselage) was added to accommodate the extra weight by distributing the weight and providing additional braking.
   The 446th and final DC-10 rolled off the production line in December 1988 and was delivered to Nigeria Airways in July 1989. The DC-10 was assembled at McDonnell Douglas's Douglas Products Division in Long Beach, California. the DC-10 ultimately proved a reliable aircraft, much loved by engineers and pilots. The original DC-10-10's notorious safety record continuously 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. Increased inspections and modifications made the DC-10 among the safest aircraft for passenger travel.

Cargo doors

The DC-10 was designed with cargo doors that opened outward instead of inward as inward-opening "plug-type" doors used on smaller pressurized aircraft. Outward-opening doors allowed larger openings required by baggage for a wide-body jet. Outward-opening doors rely on a heavy locking mechanism to secure the door against the outward force caused by the pressurization of the fuselage. In the event that the door lock malfunctioned, there was potential for explosive decompression. This was discovered in 1972 following an incident aboard American Airlines Flight 96, but no mandatory repair order was issued until the Turkish Airlines Flight 981 crash in 1974. The cargo door on all DC-10s then underwent a redesign that added an additional lock safety device to the system.

Hydraulic system

Other initial design problems included its lack of locking flap mechanisms designed to maintain their position in the event of a hydraulic failure. The lines from all three independent and redundant hydraulic systems were located in close proximity, directly beneath the tail engine. The MD-11, and later DC-10s incorporated hydraulic fuses to prevent such catastrophic loss of control in event of a hydraulic rupture.

Engine pylons

Although the design of the engine pylons was adequate, it wasn't designed to facilitate easy maintenance; the original procedure for an engine change was to detach the engine from the pylon first, which was tedious and time-consuming due to tight tolerances. To save time and costs, American and Continental Airlines both started to use a faster procedure, instructing their mechanics to remove the engine with pylon as one unit using forklift trucks. McDonnell-Douglas advised against this procedure. This procedure was very difficult to execute successfully and led to damage that was the principal cause of the crash of American Airlines Flight 191. In November 1979, the FAA fined American Airlines $500,000 for using this faulty maintenance procedure. Continental Airlines was fined $100,000 on a similar charge. in the investigation of the crash of Swissair flight 111, was used on some DC-10s. In November 2000, the FAA ordered this insulation to be removed by June 2005. The high cost of complying with the Airworthiness Directive (FAA estimates a cost of $991,010 per airplane This material has been removed from all commercial aircraft since 2005.

Variants

The DC-10 was manufactured in a number of different variants:

DC-10-10 (122 built): Original version, produced from 1970. The customers for this domestic version were American Airlines (35), Continental Airlines (8), Laker Airways (6), National Airlines (11), Turkish Airlines (3), United Airlines (46) and Western Airlines (13). The DC-10-10 was equipped with GE CF6-6 engines, which was the first civil engine from the successful CF6-family.
DC-10-10CF (9 built): Convertible passenger/cargo transport aircraft. Only built for Continental Airlines (8) and United Airlines (1).
DC-10-15 (7 built): Also known as the "DC-10 Sport", designed for use at hot high-altitude airports. The series 15 was fitted with higher-thrust GE CF6-50 powerplants. Only built for Mexican carriers Aeroméxico and Mexicana. Produced between 1979 and 1982.
DC-10-20 : Proposed but unbuilt DC-10-10 powered by Pratt & Whitney JT9D turbofans. With minimal airline interest for the original -20, the name was initially recycled to cover the Pratt-powered version of the intercontinental-range DC-10-30. Northwest, one of the launch customers for this longer-range JT9D-powered DC-10 requested the name change to -40 (see -40 entry below).

DC-10-30 (164 built): The most common model, built with General Electric CF6-50 turbofan engines and larger fuel tanks to increase range and fuel efficiency, as well as a set of rear center landing gear to support the increased weight. It was the second long-range model after the -40 and very popular with European flag carriers. Produced from 1972 to 1988, the DC-10-30 was delivered to 38 different customers, amongst which Lufthansa (11), Swissair (11), VARIG (11), KLM (10) and Iberia (9) were the largest.

DC-10-30CF (26 built): Convertible cargo/passenger transport version and delivered to Martinair Holland (4), Overseas National Airways (5), Sabena (5), Trans International Airlines (3) and World Airways (9). Sabena was the only commercial operator to fly both cargo and passengers at the same time with its DC-10-30CF.

DC-10-30ER (6 built): Extended range version. The first aircraft was delivered to Finnair in 1981, followed by Swissair with two aircraft in 1982 and finally Thai Airways International with two in 1987 and one in 1988. The -30ER aircraft have a higher Maximum Take Off Weight of 263,160 kg/580,000 lb, are powered by three GE CF6-50C2B engines each producing 54,000 lb of thrust and are equipped with an additional fuel tank in the rear cargo hold providing an additional 700 miles of range (10,620 km/6,600 mi/5,730 nm). In 1983, United Airlines leased three DC-10-30s from CP Air. These aircraft were modified to -30ER standards to allow the US carrier to fly non-stop on its Seattle-Hong Kong route. When returned to the Canadian operators these aircraft were kept in that version and two more DC-10-30s were converted by Canadian Airlines to extended range specifications.

DC-10-30AF (10 built): The all freight version production could have started in 1979 if Alitalia had confirmed its order for two aircraft then. Thus, that variant of the trijet was only launched into production in May 1984 with the first order for five aircraft from FedEx. The express carrier ordered more DC-10-30AF in July 1985 to bring its order to twelve freighters. The last two were later canceled as the carrier was building up a fleet of second hand aircraft, and reconfigured to passenger by the manufacturer and sold to Biman Bangladesh and Nigeria Airways respectively.

DC-10-40 (42 built): Produced from 1972 to 1982, this was the first long-range version, fitted with Pratt & Whitney JT9D engines. Originally designated DC-10-20, this model was renamed DC-10-40 after a special request from Northwest Orient Airlines as the aircraft was much improved compared to its original design, with a higher MTOW (in par with the Series 30) and more powerful engines, the airline's president wanted to advertise he'd the latest version.

MD-10: This was retrofit cockpit upgrade to the DC-10 and a re-designation to MD-10. The upgrade included an Advanced Common Flightdeck (ACF) used on the MD-11. The new cockpit eliminated the need for the flight engineer position and allowed common type rating with the MD-11. 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.

10 Tanker: A DC-10-10 converted into a firefighting tanker aircraft.

Incidents and accidents

"If there are in America or the world people who hesitate to fly by DC-10, those people are, like our airplane and our company, victims of a great mass of misinformation and baseless speculation. They have been misled, as we've been maligned, by so much falsehood that the truth, when it finally emerged, was scarcely recognized."
- Sanford McDonnell, 1980

The early DC-10s suffered a trying time during the 1970s when a string of notorious incidents and crashes led to a brief grounding by the United States Federal Aviation Administration.

Cargo door problem

The outward-opening cargo door design problem was first identified on June 12, 1972, when American Airlines Flight 96 lost its aft cargo door after takeoff from Detroit, Michigan, but the crew was able to perform an emergency landing with no further incident. Before Flight 96 took off, an airport employee had forced the door shut, weakening the locking pin and causing the door to blow out as the plane reached altitude. Although many carriers voluntarily modified the cargo doors and re-trained their ground crews, there wasn't yet a mandatory redesign of the system. Severe design problems still persisted with the aircraft's cargo doors, and two years after the American Airlines incident, an almost identical cargo door blow-out caused Turkish Airlines Flight 981 to crash into a forest near the town of Ermenonville shortly after leaving Orly Airport in Paris on March 3, 1974. 346 people were killed in one of the deadliest air crashes of the twentieth century, recorded in Aviation History books as the "Ermenonville air disaster". The circumstances surrounding this crash were similar to those surrounding the previous accident; however, a modified seating configuration on the Turkish aircraft exacerbated the effects of decompression which caused the floor of the aircraft to collapse into the cargo bay. Vents were not present to allow the pressure between the cargo and passenger compartments to equalize. Control cables running through the floor of the plane were severed when the floor collapsed and this rendered the aircraft uncontrollable. In the aftermath of this crash, all DC-10s underwent a mandatory door redesign.

American Airlines Flight 191

In 1979, with the cargo door issues resolved, DC-10s (all series) around the world were grounded following the crash of American Airlines Flight 191. Flight 191 lost its number one wing engine after taking off from O'Hare International Airport in Chicago, USA, May 25 1979.(External Link

) As the engine separated upwards, it ripped through the leading edge of the wing, rupturing hydraulic lines which caused a hydraulic cylinder that locked the port wing slats to fail. As airspeed was reduced per AA emergency climb-out procedures, the slats retracted, the left wing stalled, the plane rolled left and crashed before the flight crew could recover. All 271 people on board, plus two on the ground, were killed in this accident; the worst single plane crash in America.
The United States National Transportation Safety Board (NTSB) officials discovered that a maintenance procedure was the culprit: American Airlines mechanics had removed the engine and its pylon together, rather than removing the engine from the pylon then the pylon from the wing, as recommended by McDonnell Douglas. This was done using a forklift and the pylon was inadvertently cracked in the process. The short-cut procedure, thought to save several man hours on maintenance, was used by three major airlines, although McDonnell Douglas advised against it. thus ending the aircraft operations with all major airlines. Regarding the retirement of Northwest's DC-10 fleet, Wade Blaufuss, spokesman for the Northwest chapter of the Air Line Pilots Association said, "The DC-10 is a reliable airplane, fun to fly, roomy and quiet, kind of like flying an old Cadillac Fleetwood. We're sad to see an old friend go." "The DC-10 is going to be remembered as a better cargo plane than passenger plane," said Richard Aboulafia, an analyst at the Teal Group.

Specifications

	DC-10-10	DC-10-15	DC-10-30	DC-10-40
Cockpit Crew	Three
Passengers	380 (1 class), 250 (2 class)
Length		180 ft 8 in (55 m)	181 ft 7 in (55.4 m)	182 ft 3 in (55.5 m)
Height	58 ft 1 in (17.7 m)
Wingspan	155 ft 4 in (47.3 m)		165 ft 4 in (50.4 m)
Fuselage width	19 ft 9 in (6.02 m)
Fuselage height	19 ft 9 in (6.02 m)
Max interior width	18 ft 2 in (5.54 m)
Operating empty weight	240,171 lb (108,940 kg)		266,191 lb (120,742 kg)	270,213 lb (122,567 kg)
Maximum take-off weight		455,000 lb (206,385 kg)	572,000 lb (259,459 kg)	572,000 lb (259,459 kg)
Typical Cruise speed	Mach 0.82 (564 mph, 908 km/h, 490 kt)
Max Cruise speed	Mach 0.88 (610 mph, 982 km/h, 530 kt)
Max Range, loaded		4,350 mi (7,000 km)	6,220 mi (10,010 km)	5,750 mi (9,252 km)
Maximum fuel capacity		26,647 US gal (100,859 L)	36,650 US gal (138,720 L)	36,650 US gal (138,720 L)
Takeoff run on MTOW		7,257 ft (2,212 m)	9,341 ft (2,847 m)	9,242 ft (2,817 m)
Service ceiling	42,000 ft (12,802 m)
Engine model (x 3)		GE CF6-50C2F	GE CF6-50C	PW JT9D-59A
Engine thrust (x 3)		46,500 lbf (206.8 kN)	51,000 lbf (226.9 kN)	53,000 lbf (235.8 kN)

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