McDonnell Douglas DC-10


The McDonnell Douglas DC-10 is an American wide-body airliner manufactured by McDonnell Douglas.
The DC-10 was intended to succeed the DC-8 for long range flights. It first flew on August 29, 1970; and was introduced on August 5, 1971 by American Airlines.
The trijet has two turbofans on underwing pylons and a third one at the base of the vertical stabilizer.
The twin aisle layout has a typical seating for 270 in two classes.
The initial DC-10-10 had a range for transcontinental flights, and the -15 had more powerful engines for hot and high airports.
The -30 and -40 models had higher weights supported by a third main landing gear leg for an intercontinental range of up to.
Based on the -30, The KC-10 Extender is a U.S. Air Force tanker.
A design flaw in the cargo doors caused a poor safety record in early operations.
Following the American Airlines Flight 191 crash, the US Federal Aviation Administration grounded all U.S. DC-10s in June 1979.
In August 1983, McDonnell Douglas announced that production would end due to a lack of orders, as it had a widespread public apprehension after the 1979 crash and a poor fuel economy reputation.
Design flaws were rectified and fleet hours increased, for a safety record later comparable to similar era passenger jets.
Production ended in 1989, with 386 delivered to airlines along with 60 KC-10 tanker aircraft.
The DC-10 outsold the similar Lockheed L-1011 TriStar.
It was succeeded by the lengthened, heavier McDonnell Douglas MD-11.
After merging with McDonnell Douglas in 1997, Boeing upgraded many in-service DC-10s as the MD-10 with a glass cockpit to eliminate the flight engineer position.
In February 2014, the DC-10 made its last commercial passenger flight.
Cargo airlines continue to operate it as a freighter, its largest operator is FedEx Express.
The Orbis Flying Eye Hospital is a DC-10 adapted for eye surgery.
Some DC-10s are on display, while other retired aircraft are in storage.

Development

Following an unsuccessful proposal for the U.S. Air Force's CX-HLS 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. An early DC-10 design proposal was for a four-engine double-deck wide-body jet airliner with a maximum seating capacity of 550 passengers similar in length of a DC-8. The proposal was shelved in favor of a trijet single-deck wide-body airliner with a maximum seating capacity of 399 passengers, and similar in length to the DC-8 Super 60.
On February 19, 1968, in what was supposed to be a knockout blow to the competing Lockheed L-1011, George A. Spater, President of American Airlines, and James S. McDonnell of McDonnell Douglas announced American Airlines' intention to acquire the DC-10. This was a shock to Lockheed and there was general agreement within the U.S. aviation industry that American Airlines had left its competitors at the starting gate. Together with American Airlines' decision to announce the DC-10 order, it was also reported that American Airlines had declared its intention to have the British Rolls-Royce RB211 turbofan engine on its DC-10 aircraft.
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. The first DC-10, a series 10, made its maiden flight on August 29, 1970. Following a test program with 929 flights covering 1,551 hours, the DC-10 received its type certificate from the FAA on July 29, 1971. It entered commercial service with American Airlines on August 5, 1971 on a round trip flight between Los Angeles and Chicago, followed by United Airlines in mid-August. American's DC-10s had 206 seats and United's had 222; both had six-across seating in first-class and eight-across in coach. The DC-10's similarity to the Lockheed L-1011 in design, passenger capacity, and launch date resulted in a sales competition that affected profitability of the aircraft.
The first DC-10 version was the "domestic" series 10 with a range of 3,800 miles with a typical passenger load and a range of 2,710 miles with maximum payload. The series 15 had a typical load range of 4,350 miles. 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.
The series 30 and 40 were the longer-range "international" versions. The main visible difference between the models is that the series 10 has three sets of landing gear while the series 30 and 40 have an additional centerline main gear. The center main two-wheel landing gear was added to distribute the extra weight and for additional braking. The series 30 had a typical load range of 6,220 mi and a maximum payload range of 4,604 mi. The series 40 had a typical load range of 5,750 miles and a maximum payload range of 4,030 miles.
The DC-10 had two engine options and introduced longer-range variants a few years after entering service; these allowed it to distinguish itself from its main competitor, the L-1011. The 446th and final DC-10 rolled off the Long Beach, California Products Division production line in December 1988 and was delivered to Nigeria Airways in July 1989. The production run exceeded the 1971 estimate of 438 deliveries needed to break even on the project. As the final DC-10s were delivered McDonnell Douglas had started production of its successor, the MD-11.
In the late 1980s, as international travel was growing due to lower oil prices and more economic freedom, widebody demand could not be met by the delayed Boeing 747-400, MD-11 and the Airbus A330/A340 while the B747-200/300 and DC-10 production ended, and the used DC10-30s value nearly doubled from less than $20 million to nearly $40 million.

Design

The DC-10 is a low-wing cantilever monoplane, powered by three turbofan engines. Two engines are mounted on pylons that attach to the bottom of the wings, while the third engine is encased in a protective banjo-shaped structure that is mounted on the top of the rear fuselage. The vertical stabilizer with its two-segment rudder, is mounted on top of the tail engine banjo. The horizontal stabilizer with its four-segment elevator is attached to the sides of the rear fuselage in the conventional manner. The airliner has a retractable tricycle landing gear. To enable higher gross weights, the later -30 and -40 series have an additional two-wheel main landing gear, which retracts into the center of the fuselage.
It was designed for medium to long-range flights that can accommodate 250 to 380 passengers, and is operated by a cockpit flight crew of three. The fuselage has underfloor storage for cargo and baggage.

Variants

Original variants

;DC-10-10
;DC-10-10CF
;DC-10-15

Long-range variants

;DC-10-30
;DC-10-30CF
;DC-10-30ER
;DC-10-30AF
;DC-10-40

Proposed variants

;DC-10-20
;DC-10-50
;DC-10 Twin

Tanker versions

The KC-10 Extender is a military version of the DC-10-30CF for aerial refueling. The aircraft was ordered by the U.S. Air Force and delivered from 1981 to 1988. A total of 60 were built.
The KDC-10 is an aerial refueling tanker for the Royal Netherlands Air Force. These were converted from civil airliners to a similar standard as the KC-10. Also, commercial refueling companies Omega Aerial Refueling Services and Global Airtanker Service operate two KDC-10 tankers for lease. Four have been built.
The DC-10 Air Tanker is a DC-10-based firefighting tanker aircraft, using modified water tanks from Erickson Air-Crane.

MD-10 upgrade

The MD-10 is an upgrade to add a glass cockpit to the DC-10 with the re-designation to MD-10. The upgrade included an Advanced Common Flightdeck used on the MD-11 and was launched in 1996. 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.

Operators

In July 2019, there were 31 DC-10s and MD-10s in airline service with operators FedEx Express, and TAB Airlines. On January 8, 2007, Northwest Airlines retired its last remaining DC-10 from scheduled passenger service, thus ending the aircraft's operations with 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." Biman Bangladesh Airlines was the last commercial carrier to operate the DC-10 in passenger service. The airline flew the DC-10 on a regular passenger flight for the last time on February 20, 2014, from Dhaka, Bangladesh to Birmingham, UK. Local charter flights were flown in the UK until February 24, 2014.
Non-airline operators include the Royal Netherlands Air Force with two DC-10-30CF-based KDC-10 tanker aircraft, the USAF with its 59 KC-10s, and the 10 Tanker Air Carrier with its modified DC-10-10 used for fighting wildfires. Orbis International has used a DC-10 as a flying eye hospital. Surgery is performed on the ground and the operating room is located between the wings for maximum stability. In 2008, Orbis chose to replace its aging DC-10-10 with a DC-10-30 jointly donated by FedEx and United Airlines. The newer DC-10 converted into MD-10 configuration, and began flying as an eye hospital in 2010. One former American Airlines DC-10-10 is operated by the Missile Defense Agency as the Widebody Airborne Sensor Platform.

Accidents and incidents

As of September 2015, the DC-10 had been involved in 55 accidents and incidents, including 32 hull-loss accidents, with 1,261 occupant fatalities. Of these accidents and incidents, it has been involved in nine hijackings resulting in one death and a bombing resulting in 170 occupant fatalities. Despite its poor safety record in the 1970s, which gave it an unfavorable reputation, the DC-10 has proved to be a reliable aircraft with a low overall accident rate as of 1998. The DC-10's initially poor safety record has 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.

Cargo door problem and other major accidents

Instead of conventional inward-opening plug doors, the DC-10 has cargo doors that open outward; this allows the cargo area to be completely filled, as the doors do not occupy otherwise usable interior space when open. To overcome the outward force from pressurization of the fuselage at high altitudes, outward-opening doors must use heavy locking mechanisms. In the event of a door lock malfunction, there is great potential for explosive decompression.

American Airlines Flight 96

On June 12, 1972, American Airlines Flight 96 lost its aft cargo door above Windsor, Ontario. Before takeoff, an airport employee had forced the door shut, and although the door appeared secure, the internal locking mechanism was not fully engaged. When the aircraft reached approximately in altitude, the door blew out, and the resulting explosive decompression collapsed the cabin floor. Many control cables to the empennage were cut, leaving the pilots with very limited control of the aircraft. The crew performed an emergency landing by using the ailerons, right elevator, some limited rudder trim, and asymmetrical thrust of the wing engines. All 67 passengers evacuated safely.
U.S. National Transportation Safety Board investigators found the cargo door design to be dangerously flawed, as the door could be closed without the locking mechanism fully engaged, and this condition was not apparent from visual inspection of the door nor from the cargo-door indicator in the cockpit. The NTSB recommended modifications to make it readily apparent to baggage handlers when the door was not secured, and also recommended adding vents to the cabin floor, so that in an explosive decompression, the pressure difference between the cabin and cargo bay could quickly equalize without damaging other aircraft systems. Although many carriers voluntarily modified the cargo doors, no airworthiness directive was issued, due to a gentlemen's agreement between the head of the FAA, John H. Shaffer, and the head of McDonnell Douglas's aircraft division, Jackson McGowen. McDonnell Douglas made some modifications to the cargo door, but the basic design remained unchanged, and problems persisted.

Turkish Airlines Flight 981

On March 3, 1974, in an accident circumstantially similar to American Airlines Flight 96, a cargo-door blowout caused Turkish Airlines Flight 981 to crash near Ermenonville, France. All 346 people on board died in one of the deadliest air crashes of all time. The cargo door of Flight 981 had not been fully locked, though it appeared so to both cockpit crew and ground personnel. The Turkish aircraft had a seating configuration that exacerbated the effects of decompression, and as the cabin floor collapsed into the cargo bay, control cables were severed and the aircraft became uncontrollable. 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. Following this crash, a special subcommittee of the United States House of Representatives investigated the cargo-door issue and the certification by the Federal Aviation Administration of the original design. An airworthiness directive was issued, and all DC-10s underwent mandatory door modifications. The DC-10 experienced no more major incidents related to its cargo door after FAA-approved changes were made.

American Airlines Flight 191

On May 25, 1979, American Airlines Flight 191 crashed immediately after takeoff from Chicago's O'Hare Airport. As the airliner was taking off, the left engine and pylon assembly swung upward over the top of the wing, severing critical hydraulic and electrical lines before falling away. The leading edge slat actuators lost hydraulic pressure and the slats retracted due to aerodynamic forces, causing the left wing to stall. This condition, combined with asymmetric thrust due to the missing engine, caused the aircraft to rapidly roll to the left, descend, and crash, killing all 271 people on board and two individuals on the ground. The loss of Flight 191 remains the deadliest single-aircraft aviation accident in U.S. history. The crash and its aftermath were widely covered by the media and dealt a severe blow to the DC-10's reputation and sales.
The crash highlighted major deficiencies in the DC-10 design: the lack of a mechanism to lock the leading-edge slats in the event of a hydraulic or pneumatic actuation failure; a lack of redundancy in the stall warning system; and the failure of McDonnell Douglas to adequately consider "multiple failures of other systems" that could result from an in-flight pylon separation. Critical warning system components were torn away with the engine, thus preventing the flight crew—who could not see the wings from the cockpit—from realizing the cause of their predicament and taking appropriate corrective action. Following the crash, the FAA withdrew the DC-10's type certificate on June 6, 1979, grounding all 138 U.S.-registered DC-10s along with those from other nations with bilateral agreements with the United States, and banning all other DC-10s from U.S. airspace. Even ferry flying within U.S. airspace was forbidden except to allow foreign air carriers to return their DC-10s to overseas maintenance bases. These measures were rescinded five weeks later on July 13, 1979, after modifications were made to the slat actuation and position systems, along with stall warning and power supply changes.
NTSB officials discovered that American Airlines mechanics had removed the engine and its pylon as a unit, rather than removing the engine from the pylon before removing the pylon from the wing, as recommended by McDonnell Douglas. The non-standard procedure caused structural damage that the NTSB deemed to have caused the engine separation and the subsequent crash. It was later discovered that this short-cut procedure, believed to save many man-hours, was being used by both American Airlines and Continental Airlines, although McDonnell Douglas had advised against it. In November 1979, the FAA fined American Airlines $500,000 and Continental Airlines $100,000 for using this incorrect maintenance procedure.
In the wake of the grounding, the FAA convened a safety panel under the auspices of the National Academy of Sciences to evaluate the design of the DC-10 and the U.S. regulatory system in general. The panel's report, published in June 1980, found "critical deficiencies in the way the Government certifies the safety of American-built airliners", focusing on a shortage of FAA expertise during the certification process and a corresponding overreliance on McDonnell Douglas to ensure that the design was safe. Writing for The Air Current, aviation journalist Jon Ostrower likens the panel's conclusions to those of a later commission convened after the 2019 grounding of the Boeing 737 MAX. Ostrower faults both manufacturers for focusing on the letter of the law regarding regulatory standards, taking a design approach that addresses how the pilots could address single system failures, without adequately considering scenarios in which multiple simultaneous malfunctions of different systems could occur.

United Airlines Flight 232

On July 19, 1989, United Airlines Flight 232 crashed at Sioux City, Iowa after the tail engine suffered an uncontained engine failure earlier in the flight, disabling all hydraulic systems and rendering most flight controls inoperable. The flight crew, led by Captain Al Haynes and assisted by DC-10 flight instructor flying as a passenger, managed to perform a partially controlled emergency landing by constantly adjusting the thrust of the remaining two engines; 185 people on board survived, but 111 others died, and the aircraft was destroyed.
The DC-10 lacks non-hydraulic backup flight controls because the control surfaces are too large to be operated easily without hydraulic assistance, and it was considered extremely improbable that all three hydraulic systems would fail. However, due to their close proximity under the tail engine, the engine failure ruptured all three, resulting in total loss of control to the elevators, ailerons, spoilers, horizontal stabilizer, rudder, flaps and slats. Following the accident, hydraulic fuses were installed in the #3 hydraulic system below the tail engine on all DC-10 aircraft to ensure that sufficient control remains if all three hydraulic systems are damaged in this area. It is still possible to lose all three hydraulic systems elsewhere. This nearly happened to a cargo airliner in 2002 when a main-gear tire exploded in the left wing wheel well, causing total loss of pressure in the #1 and the #2 hydraulic systems. The #3 system was dented but not penetrated.

Other notable accidents

Other notable accidents are:

Deliveries

1971197219731974197519761977197819791980198119821983198419851986198719881989Total
1352574842191418364025111210111710101446

Citations