| DC-10 | |
|---|---|
![]() |
|
| A FedEx Express MD-10-10 | |
| Role | Wide-body jet airliner |
| National origin | United States |
| Manufacturer | McDonnell Douglas |
| First flight | August 29, 1970 |
| Introduction | August 5, 1971 with American Airlines |
| Status | In service |
| Primary users | FedEx
Express Omni Air International World Airways Arrow Air |
| Produced | 1968-1988 |
| Number built | DC-10: 386 KC-10: 60 |
| Variants | KC-10 Extender |
| Developed into | McDonnell Douglas MD-11 |
The McDonnell Douglas DC-10 is a three-engine widebody airliner, with two engines mounted on underwing pylons and a third engine at the base of the vertical stabilizer. The DC-10 has range for medium to long haul flights. The model was a successor to the company's DC-8 for long-range operations, and competed in the same markets as the Lockheed L-1011 Tristar, which has a similar layout to the DC-10.
Production of the DC-10 ended in 1989 with 386 delivered to airlines and 60 to the U.S. Air Force as air-to-air refueling tankers, designated the KC-10 Extender.[1] The DC-10 was succeeded by the related McDonnell Douglas MD-11 which entered service in 1990.
Contents |
Following an unsuccessful proposal for the US Air Force's CX-HLS (Heavy Logistics System) in 1965, Douglas Aircraft began design studies based on its CX-HLS design. In 1966, American Airlines offered a specification to manufacturers for a widebody aircraft smaller than the Boeing 747 but capable of flying similar long-range routes from airports with shorter runways. The DC-10 became McDonnell Douglas's first commercial airliner after the merger between McDonnell Aircraft Corporation and Douglas Aircraft Company in 1967.[2]
The DC-10 was first ordered by launch customers American Airlines with 25 orders, and United Airlines with 30 orders and 30 options in 1968.[3] The DC-10, a series 10 model, made its first flight on August 29, 1970.[4] Following a flight test program with 929 flights covering 1,551 hours, the DC-10 was awarded a type certificate from the FAA on July 29, 1971.[5] It entered commercial service with American Airlines on August 5, 1971 on a round trip flight between Los Angeles and Chicago. United Airlines began DC-10 service on August 16, 1971.[6] The DC-10's similarity to the L-1011 in terms of passenger capacity and launch in the same timeframe resulted in a head to head sales competition which affected profitability of the aircraft.
The first DC-10 version was the "domestic" series 10 with a range of 3,800 miles (3,300 nmi, 6,110 km) with a typical passenger load and a range of 2,710 miles (2,350 nmi, 4,360 km) with maximum payload. The series 15 had a typical load range of 4,350 miles (3,780 nmi, 7,000 km).[7][8] 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 the aircraft was much improved over the original design. The FAA issued the Series 40 certificate on October 27, 1972.[9]
The series 30 and 40 were the longer range "international" versions. 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 two-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 series 30 had a typical load range of 6,220 mi (10,010 km) and a maximum payload range of 4,604 mi (7,410 km). The series 40 had a typical load range of 5,750 miles (9,265 km) and a maximum payload range of 4,030 miles (3,500 nmi, 6,490 km).[7][10]
Eventually, the DC-10 was able to distinguish itself from its competitors with two engine options, as well as earlier introduction of longer range variants than the L-1011. The 446th and final DC-10 rolled off the production line in December 1988 and was delivered to Nigeria Airways in July 1989.[11] The DC-10 was assembled at McDonnell Douglas's Douglas Products Division in Long Beach, California.[1] As the final few DC-10 deliveries were occurring, McDonnell Douglas had already started production of the DC-10's successor, the MD-11.[12]
The DC-10 is a low-wing cantilever monoplane with a conventional tail unit with a single fin and rudder. It is powered by two turbofan engines mounted on underwing pylons and a third engine at the base of the vertical stabilizer. It has a retractable tricycle landing gear. The later series 30 and 40 have an additional two-wheel main landing gear on the centerline of the fuselage. It was designed to be a medium to long-range airliner with a widebody fuselage to seat over 250 passengers. It is operated by a flight-crew of three located on the flightdeck in the nose on the same level as the passenger cabin. The fuselage has underfloor stowage for cargo and baggage.
The DC-10 was manufactured in a number of different variants:
As of August 2009, the DC-10 was involved in 55 incidents,[20] including 30 hull-loss accidents,[21] with 1,261 fatalities.[22]
Despite its troubled beginnings in the 1970s, which gave it an unfavorable reputation,[23] the DC-10 has proved a reliable aircraft.[24] The original DC-10-10's bad safety record continuously improved as design flaws were rectified and fleet hours increased. The DC-10's lifetime safety record is comparable to similar second-generation passenger jets as of 2008.[25]
A problem with the outward-opening cargo door was first identified on June 12, 1972, when American Airlines Flight 96 lost its aft cargo door after takeoff from Detroit, Michigan. Fortunately, the crew was able to perform an emergency landing with some of the aircraft's control surfaces disabled. Aileron controls and differential thrust of the wing engines were used to control the DC-10.[26] 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 airliner reached altitude.[27]
The DC-10 was designed with cargo doors that opened outward instead of inward-opening "plug-type" doors. Using outward-opening doors allowed the cargo area to be completely filled since the door was not occupying usable space. To secure the door against the outward force caused by the pressurization of the fuselage, outward-opening doors rely on a heavy locking mechanism. In the event of a complete door lock malfunction, there was potential for explosive decompression.[28]
Although many carriers voluntarily modified the cargo doors and re-trained their ground crews, there was not yet a mandatory rework of the system. Severe 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 Paris on March 3, 1974. 346 people were killed in one of the deadliest air crashes of the twentieth century. Circumstances of this crash were similar to 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. As part of the DC-10 design, vents were not adequate 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.[29] Following this crash, all DC-10s underwent mandatory door modifications.[30]
In 1979, with the cargo door issues resolved, the DC-10s experienced another major accident with 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.[31] 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.[32] 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.[32][33]
The Chicago incident also highlighted a major deficiency in the DC-10 design—its lack of a locking mechanism to maintain the position of the leading-edge slats in the event of a hydraulic or pneumatic failure.[32] Other wide-body aircraft of the day carried such a feature. Another deficiency highlighted in the NTSB report was the vulnerable placement of wiring at the leading edge (front) of the wing. When the engine pulled up and over the wing, it tore out these lines, thus rendering vital warning instruments in the cockpit inoperable. Other aircraft of this era typically placed this kind of wiring in the center of the wing, in a less vulnerable position. Following the Chicago crash, the type certificate of the DC-10 was withdrawn by the FAA, grounding the aircraft, on June 6, 1979. The aircraft resumed service after modifications which prevented the slats retracting in the event of a hydraulic leak.
Another instance of a DC-10 crash was the Flight 232 disaster at Sioux City, Iowa, USA, on July 19, 1989. After the #2 engine (tail engine) suffered an uncontained fan disk failure in flight which ruptured critical hydraulic lines, the crew, led by Captain Al Haynes and assisted by a senior pilot flying as a passenger (Dennis E. "Denny" Fitch), performed an emergency landing by varying remaining engine power to control the plane. The crew managed to fly the aircraft onto the runway in a partially controlled manner and 185 of the 296 people on board survived. The aircraft was destroyed in the landing attempt.
The Sioux City crash concerned investigators because the total loss of hydraulic pressure aboard the DC-10 was considered nearly impossible. The design had lines from all three independent and redundant hydraulic systems in close proximity, directly beneath the #2 (tail) engine. Debris from the #2 fan disk separation failure penetrated all three lines resulting in total loss of control to the elevators, ailerons and rudder.[34]
The locking flap mechanisms were designed to maintain their position in the event of a hydraulic failure. Later DC-10s and the MD-11 incorporated hydraulic fuses to prevent such catastrophic loss of control in event of a hydraulic rupture.[35]
Other notable incidents and accidents involving the DC-10 are listed below.
The Air France Concorde crash of 2000 was attributed to a fragment of titanium that fell from the thrust reverser of a Continental Airlines DC-10 that had taken off some four minutes earlier. This fragment was traced to a third party parts replacement which had not been approved by the FAA.
On January 8, 2007, Northwest Airlines retired its last remaining DC-10 being used for scheduled passenger service, replacing it with an Airbus A330 for a route between Minneapolis-St. Paul and Honolulu,[38] 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."[39] "The DC-10 is going to be remembered as a better cargo plane than passenger plane," said Richard Aboulafia, an analyst with the Teal Group.[39] In November 2006, ATA Airlines announced it had purchased seven of Northwest's remaining DC-10s, to replace ATA's L-1011 airplanes. Omni Air International purchased six of Northwest's DC-10 aircraft.[40]
The aging models are now largely being used as dedicated freight aircraft. American Airlines and United Airlines have sold their large DC-10-10 fleets to cargo carrier FedEx. Many have been modernized to MD-10s by adding a glass cockpit, which eliminates the need for a flight engineer. Other DC-10 aircraft continue in charter and cargo services with their three-person flight deck configuration. Omni Air International and World Airways, continue to operate the DC-10 on charter passenger services as well as for the Air Mobility Command. Biman Bangladesh Airlines operates five DC-10-30s as one of their primary passenger aircraft as of 2009.[41]
Non-airline operators include the Royal Netherlands Air Force with three DC-10-30CFs converted to KDC-10 flying tankers, the USAF with its 59 KC-10, the 10 Tanker Air Carrier with its modified DC-10-10 used for fighting wildfires,[42] and Orbis International, which uses a single DC-10-10 converted into a flying eye hospital. Surgery is performed on the ground (not in flight) and the operating room is located between the wings for maximum stability.[43]
As of July 2009, there were 150 DC-10s in service with commercial operators, including FedEx Express (85), Omni Air International (12), World Airways (12), Arrow Cargo (7), Cielos Airlines (5), Avient Aviation (4), Biman Bangladesh Airlines (4), Garuda Indonesia Airways (4) and others with fewer aircraft.[44]
| DC-10-10 | DC-10-15 | DC-10-30 | DC-10-40 | |
|---|---|---|---|---|
| Cockpit crew | Three | |||
| Passengers | 380 (1 class), 250 (2 class) | |||
| Cargo (freighter variant) | 22 LD7 pallets | 23 LD7 pallets | ||
| Fuselage length | 170 ft 6 in (51.97 m) | |||
| Height | 58 ft 1 in (17.7 m) | |||
| Wingspan | 155 ft 4 in (47.34 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 | 430,000 lb (195,045 kg) |
455,000 lb (206,385 kg) |
572,000 lb (259,459 kg) |
555,000 lb (251,701 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 | 3,800 miles (6,114 km) | 4,350 mi (7,000 km) | 6,220 mi (10,010 km) | 5,750 mi (9,252 km) |
| Maximum fuel capacity | 21,700 US gal (82,134 L) |
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 | 8,612 ft (2,625 m) | 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 CF6-6D | GE CF6-50C2F | GE CF6-50C | PW JT9D-59A |
| Engine thrust (x 3) | 40,000 lbf (177.9 kN) | 46,500 lbf (206.8 kN) | 51,000 lbf (226.9 kN) | 53,000 lbf (235.8 kN) |
| 1971 | 1972 | 1973 | 1974 | 1975 | 1976 | 1977 | 1978 | 1979 | 1980 | 1981 | 1982 | 1983 | 1984 | 1985 | 1986 | 1987 | 1988 | 1989 | Total |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 13 | 52 | 57 | 48 | 42 | 19 | 14 | 18 | 36 | 40 | 25 | 11 | 12 | 10 | 11 | 17 | 10 | 10 | 1 | 446 |
Related development
Comparable aircraft
|
|||||||||||
|
||||||||||||||
|
|