DC-10 | |
---|---|
|
|
A FedEx Express MD-10-10, a modernized DC-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 |
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 turbofan 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 flight deck 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 five main variants with two other variants proposed.
The DC-10-10 was the original passenger version, produced from 1970. The DC-10-10 was equipped with GE CF6-6 engines, which was the first civil engine from the successful CF6-family. 122 were built.
The DC-10-10CF is a convertible passenger/cargo transport version of the -10. Nine were built for Continental Airlines (8) and United Airlines (1).
The DC-10-15 variant was designed for use at hot high-altitude airports. The series 15 was basically a -10 fitted with higher-thrust GE CF6-50C2F (derated DC-10-30 engines) powerplants. Built for only Mexican carriers Aeroméxico and Mexicana.[13] 7 were built between 1979 and 1982.
The DC-10-20 was a proposed version of the 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 DC-10-40 (see -40 entry below).
The DC-10-30 was the most common model produced. It was 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. 163 built from 1972 to 1988 and delivered to 38 different customers.
The DC-10-30CF is the convertible cargo/passenger transport version of the -30. 26 were built with deliveries 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.
The DC-10-30ER is the extended range version of the -30. 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 580,000 lb (263,160 kg), 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 mi (6,600 mi/5,730 nmi/10,620 km) of range. 6 were built and 5 -30s were later converted to -30ERs.
The DC-10-30AF was the all freight version of the -30. Production could have started in 1979 if Alitalia had confirmed its order for two aircraft then. But production began in May 1984 after the first order for five aircraft from FedEx. 11 were built.
The DC-10-40 is 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 (on par with the Series 30) and more powerful engines, the airline's president wanted to advertise he had the latest version. Northwest Orient Airlines and Japan Airlines were the only airlines to order the series 40 with 22 and 20 aircraft respectively. The DC-10-40s delivered to Northwest were first equipped with three Pratt & Whitney JT9D-15 producing 45,700 lbf (203.3 kN) of take off thrust, before the introduction of the JT9D-25W, generating 50,000 lbf (222.4 kN) of thrust through water injection),[14] and had a MTOW of 555,000 lb (251,815 kg), while those produced for Japan Airlines were equipped with P&W JT9D-49A that produced a maximum thrust of 53,000 lbf (235.8 kN) and had a MTOW of 565,000 lb (256,350 kg). 42 were built from 1973 to 1983.[15]
The DC-10-50 was a proposed version with Rolls-Royce RB211-524 engines for British Airways. Such an order never came and the plans for the DC-10-50 were abandoned.[16]
The KC-10 Extender is a military version of the DC-10-30 for aerial refueling. The aircraft was ordered by the U.S. Air Force. Produced from 1981. 60 were built.
The KDC-10 is an aerial refueling tanker for the Royal Netherlands Air Force. These were converted from civil airliners (DC-10-30CF) to a similar standard as the KC-10. Also, commercial refueling companies Omega Air and Global Airtanker Service operate two KDC-10 tanker for lease. Four have been built.[17][18]
The 10 Tanker Air Carrier is a DC-10-10 converted into a firefighting tanker aircraft, using modified water tanks from Erickson Air-Crane.
The MD-10 is 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.[19] 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 FedEx Express, which operate both the MD-10 and MD-11, to have a common pilot pool for both aircraft. The MD-10 conversion now falls under the Boeing Converted Freighter program where Boeing's international affiliate companies perform the conversions.[20]
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,[21] 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."[22] "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.[22] 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.[23]
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.[24]
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, and the 10 Tanker Air Carrier with its modified DC-10-10 used for fighting wildfires.[25] Orbis International 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.[26] Orbis has chosen to replace their aging DC-10 with a MD-10.[27] The project began in 2008, finally materialized when FedEx and United Airlines jointly donated a DC-10 for conversion.[28] The MD-10 eye hospital is expected to be flying in 2010.[28][29]
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) and others with fewer aircraft.[30]
As of August 2009, the DC-10 was involved in 55 incidents,[31] including 30 hull-loss accidents,[32] with 1,261 fatalities.[33]
Despite its troubled beginnings in the 1970s, which gave it an unfavorable reputation,[34] the DC-10 has proved a reliable aircraft.[35] 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.[36]
The DC-10 was designed with cargo doors that opened outward instead of conventional inward-opening "plug-type" doors which, due to their being larger than the door frame, make opening the door impossible once the plane is pressurized. Using outward-opening doors allowed the DC-10's cargo area to be completely filled since the door was not occupying usable space. However, to secure the door against the outward force caused by the pressurization of the fuselage at high altitudes, outward-opening doors must rely on heavy locking mechanisms. And in the event of a door lock malfunction, there is great potential for explosive decompression.[37]
A problem with the outward-opening cargo door was first publicly exposed on June 12, 1972, when American Airlines Flight 96 lost its aft cargo door shortly after takeoff from Detroit, Michigan. Before Flight 96 took off, an airport employee had forced the door shut, which, due to the cargo door's design, gave an outward appearance of being securely locked despite the internal locking mechanism not being fully engaged. Subsequently, when the plane reached approximately 11,750 feet (3,580 m) in altitude, the cargo door blew out, causing an explosive decompression which partially collapsed the cabin floor at the rear of the plane. This collapsed section of the floor cut or impeded many of the control cables to the empennage control systems necessary to fly the plane.[38][39] The crew was able to accomplish an emergency landing by using the ailerons, right elevator, some limited rudder trim and asymmetrical thrust of the wing engines.[40]
During the investigation of the near-crash of Flight 96, NTSB investigators found that the DC-10's cargo door design was dangerously flawed. The door relied on a set of heavy steel hooks to secure it against the door frame. When the hooks were fully engaged, an outside lever on the cargo door could be depressed, which drives a set of locking pins through the hooks, holding them in place. However, the NTSB investigation found that it was possible to close the outside lever without the hooks being fully engaged. Additionally, there would be no outward signs that the locking mechanism was not engaged, and even though the hooks and locking pins were not in the closed position, the cargo door indicator in the cockpit would still register the door as being secured. This combination of factors caused Flight 96 to take off without its aft cabin door being fully locked. And when the door blew out at altitude, the sudden decompression of the airplane caused a large pressure difference to build up between the cabin above and the cargo bay below. This depressurization loading is what caused the cabin floor to collapse.[41] And because the DC-10 was designed with its hydraulics and control wires routed through the floor beams, the collapse of the cabin floor caused a loss of vital flight controls.[38]
Following the Windsor incident investigation, the NTSB made several recommendations, including fixing the faulty cabin door design to make it impossible for baggage handlers to close the cargo door lever without the locking pins being fully engaged. It was also recommended that vents be installed in the cabin floor so that, in case of an explosive decompression, the pressure difference between the cabin and cargo bay could quickly be equalized without collapsing the cabin floor and damaging critical control systems.[41] Although many carriers voluntarily modified the cargo doors, there was not yet a mandatory rework of the system due to a gentlemen's agreement between the head of the FAA and McDonnell Douglas, which prevented an airworthiness directive from being issued, which would have grounded all DC-10s until the problem had been fixed. McDonnell Douglas did make some modifications to the cargo door, but the basic design remained unchanged and severe problems still persisted.[41]
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.[41] 346 people were killed[42] in one of the deadliest air crashes of all time. Circumstances of this crash were near identical to the previous incident. Again, the cargo door had not been fully locked, though it appeared so to both cockpit crew and ground personnel. The Turkish aircraft had a modified seating configuration that exacerbated the effects of decompression, which caused the aircraft's floor to collapse into the cargo bay. Control cables running through the floor of the plane were severed when the floor collapsed and this rendered the aircraft uncontrollable.[41] Crash investigators found that the DC-10's relief vents were not large enough to equalize the pressure between the passenger and cargo compartments during explosive decompression.[42] Following this crash, a congressional hearing was called to investigate why another DC-10 incident occurred involving its aft cargo door after the problems had been identified. Subsequently, several lawsuits were filed when it was discovered that McDonnell Douglas had been warned about the design of the cargo door by its subcontractor. McDonnell Douglas knew about the problem 4 years earlier during development when the cabin door failed during a pressurization test yet failed to take appropriate actions. As a consequence, the airplane manufacturer was forced to pay over $80 million in damages. An airworthiness directive was issued, and all DC-10s underwent mandatory door modifications.[43] The DC-10 experienced no more major incidents related to its cargo door after FAA-approved changes were made.[41]
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, left wing engine after taking off from O'Hare International Airport in Chicago, USA, May 25, 1979.[44] As the engine separated upwards, it ripped through the leading edge of the wing, rupturing hydraulic lines. Without hydraulic pressure, the left wing leading edge slats retracted due to the force of the air moving over the wings. That, in turn, increased the stall speed of the left wing above the engine-failure climb out speed, being used by the pilots. When the left wing stalled, the plane rapidly rolled to the left and crashed before the flight crew could recover. All 271 people on board, plus two on the ground, were killed; 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.[45] 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.[45][46]
The Chicago accident 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.[45] 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. 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, spoilers, horizontal stabilizer, rudder, flaps and slats.[47]
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.[48]
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.
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
|
|