The McDonnell Douglas DC-9 (initially known as the Douglas DC-9) is a twin-engine, single-aisle jet airliner. It was first manufactured in 1965 with its first flight later that year. The DC-9 was designed for frequent, short flights. The final DC-9 was delivered in October 1982.

The DC-9 was followed in subsequent modified forms by the MD-80, MD-90 and Boeing 717. With the final two deliveries of the 717 on May 23, 2006, production of the DC-9 aircraft family ceased after 41 years.

Design and development

The first DC-9, a production ship, flew in February 1965. The second DC-9 flew a few weeks later and entered service with Delta Air Lines in late 1965. The initial Series 10 would be followed by subsequent growth variants. The final DC-9 series was the -50, which first flew in 1974. The DC-9 was a commercial success with 976 built when the production ended in 1982.

The DC-9 is one of the longest lasting aircraft in operation. Its reputation for reliability and efficiency drove strong sales of its successors well into the 2000s. The DC-9 family is one of the most successful jet airliners with a total of over 2,400 units produced; it ranks third behind the second place Airbus A320 family with over 3,000 produced, and the first place Boeing 737 with over 5,000 produced.

The DC-9 was followed by the introduction of the MD-80 series in 1980. The MD-80 series was originally called DC-9-80 series. It was a lengthened DC-9-50 with a higher maximum take-off weight (MTOW), a larger wing, new main landing gear, and higher fuel capacity. The MD-80 series features Pratt & Whitney JT8D engines with higher thrust ratings than those on the DC-9.

The MD-80 series was further developed into the McDonnell Douglas MD-90 in the early 1990s. It has yet another fuselage stretch, a glass cockpit (first introduced on the MD-88) and completely new high-bypass International Aero V2500 engines. In comparison to the very successful MD-80, relatively few MD-90 examples were built.

The final variant of the DC-9 family was the MD-95, which was renamed the Boeing 717-200 after McDonnell Douglas's merger with Boeing in 1997 and before aircraft deliveries began. The fuselage length and wing are highly similar to those found on DC-9-30 aircraft, but much use was made of lighter, modern materials. Power is supplied by two BMW/Rolls-Royce BR715 high bypass turbofan engines.

In 2008, DC-9s and derivative models (except MD-90 and 717) are considered gas guzzlers. Studies aimed at improving DC-9 fuel efficiency, by means of retrofitted wingtip extensions of various types, have not succeeded in demonstrating significant benefits. With the existing fleets shrinking, modifications do not appear to be likely to occur, especially since the wing design makes retrofitting difficult. Thus, DC-9s are likely to be further replaced in service by new Boeing 737, Airbus A320, Embraer E-Jets aircraft, or the new, emerging Bombardier C-series airliner. However, it is probable that a modest number of DC-9s will continue to productively fly for many years to come.

Variants

DC-9-10: The earliest and smallest DC-9 series was 104.4 feet (31.8 m) long and had a maximum weight of 41 tonnes. Power was a pair of 12,500 lbf (62.3 kN) Pratt & Whitney JT8D-5 or 14,000 lb_f (62.3 kN) JT8D-7 engines. A total of 137 were built. Models -11, -12, -13, -14, -15, -15F and -15RC were produced. Delta Air Lines was the initial operator.

DC-9-20: This was designed to satisfy a Scandinavian Airlines request for improved short field performance by using the more powerful engines and improved wings of the -30 combined with the shorter fuselage used in the -10. Ten Series 20 aircraft were produced, all of them Model -21. As of April 2008, one DC-9-21 operated as a skydiving jump platform at Perris Valley Airport in Perris, CA (USA). With the steps on the ventral stairs removed, it is the only airline transport class jet certified by the FAA for skydiving operations.

DC-9-30: The -30 was the definitive series with 662 produced, accounting for about 60% of production. The -30 entered service with Eastern Airlines in February 1967 with a 14 ft 9 in (4.50 m) fuselage stretch, wingspan increased by just over 3 feet (0.9 m) and full-span leading edge slats, improving takeoff and landing performance. Gross take-off weight was typically 110,000 lb (50,000 kg). Engine options for Models -31, -32, -33 and -34 included the P&W JT8D-7, JT8D-9 rated at 14,500 lbf (65 kN) of thrust, or JT8D-11 rated at 15,000 lbf (69 kN) of thrust.

DC-9-40: This further lengthened version entered service with SAS in March 1968. With a 6 ft 6 in (2 m) longer fuselage, accommodation was up to 125 passengers. The -40 was fitted with Pratt & Whitney engines of between (64.5 and 71 kN). A total of 71 were produced.

DC-9-50: The -50 was the largest DC-9 to fly. It features an 8 ft 2 in (2.5 m) fuselage stretch and seats up to 139 passengers. It started revenue service in August 1975 with Eastern Airlines and included a number of detail improvements, a new cabin interior, and more powerful JT8D-15 or -17 engines in the (71-73 kN) class. McDonnell Douglas delivered 96, all as Model -51. Some visual cues to distinguish this version from other DC-9 variants include side strakes (fins) below the side cockpit windows and thrust reversers rotated about 22 degrees.

Military and government

C-9: Several -30 (with side cargo door) series were purchased by the US armed forces. The C-9A Nightingale medevac configuration was for the U.S Air Force. The C-9B Skytrain II was for the U.S Navy and Marines, used for fleet logistics support moving both personnel and light cargo. The VC-9C is a VIP transport version for the US Air Force.

Versions of the DC-9 are also used by the Kuwait Air Force and Italian Air Force.

Operators

Northwest Airlines operates a fleet of DC-9 aircraft, most of which are over 30 years old. With severe increases in fuel prices in the summer of 2008, Northwest Airlines finally began retiring its DC-9s, switching to Airbus A319s that are 27% more fuel efficient.

Incidents and accidents

Notable accidents

• On October 1, 1966 West Coast Airlines Flight 956 crashed with eighteen fatalities and no survivors. This accident marks the first loss of a DC-9.
• On February 15, 1970, a Dominicana de Aviacion DC-9 crashed after taking off from Santo Domingo. The crash, caused by contaminated fuel, killed all 101 passengers and crew.
• On May 2, 1970, an Overseas National Airways DC-9, wet-leased to ALM Dutch Antilles Airlines and operating as ALM Flight 980, ditched in the Caribbean Sea on a flight from New York's John F. Kennedy International Airport to Princess Juliana International Airport on Sint Maarten. After three landing attempts in poor weather at Sint Maarten, the pilots began to divert to their alternate of Saint Croix, U.S. Virgin Islands but ran out of fuel 30 miles short of the island. After about 10 minutes, the aircraft sank in 5,000 feet of water and was never recovered. 40 people survived the ditching, 23 perished.

• On November 14, 1970, a Southern Airways Flight 932 DC-9 crashed into a hill near Tri-State Airport in Huntington, West Virginia. All 75 on board were killed (including 37 members of the Marshall University Thundering Herd football team, eight members of the coaching staff, 25 boosters, and others).
• On January 26, 1972, Jugoslovenski Aero Transport Flight JU364 DC-9-32 (registration: YU-AHT) was destroyed in flight by a bomb placed on the aircraft. The sole survivor was a flight attendant, Vesna Vulović, who holds the record for the world's longest fall without a parachute when she fell from 33,000 ft (10,160 m) inside the tail section of the airplane and survived.
• On September 11, 1974, Eastern Air Lines Flight 212 DC-9-30 crashed just short of the runway at Charlotte, North Carolina, killing 71 of the occupants.
• On September 10, 1976, an Inex-Adria Aviopromet DC-9 collided with a British Airways Trident over the Croatian town of Vrbovec, killing all 176 people aboard both aircraft.
• On April 4, 1977, a Southern Airways Flight 242 DC-9-31 crash landed onto then a highway in New Hope, Georgia, US. The flight crew and 60 passengers were killed during the forced landing due to impact forces and fire, but 19 of the passengers survived, as well as both flight attendants. Eight people on the ground were also killed.
• On June 26, 1978, Air Canada Flight 189 DC-9 overran the runway in Toronto after a blown tire aborted the takeoff. 2 of 107 passengers and crew were killed.
• On September 14, 1979, ATI Flight BM12 DC-9-32 crashed in the mountains of Conca D'Oru near Cagliari while approaching to Cagliari Elmas airport. All 27 passengers and 4 crew members died in the crash and in the following fire.
• On June 27, 1980, a DC-9-15 carrying Aerolinee Itavia Flight 870 suffered an in-flight explosion and crashed into the sea near the Italian island of Ustica. All 81 people on board were killed. The causes of this accident are still unclear.

• On December 1, 1981, Inex-Adria Aviopromet Flight 1308 crashed in the mountains while approaching Campo dell'Oro Airport in Ajaccio, Corsica killing 173 passengers and 7 crew members.
• On June 2, 1983, Air Canada Flight 797 DC-9 experienced an electrical fire in the aft lavatory during flight, resulting in an emergency landing at Cincinnati/Northern Kentucky International Airport. During evacuation, the sudden influx of oxygen caused a flash fire throughout the cabin, resulting in the deaths of 23 of the 41 passengers, including Canadian folk singer Stan Rogers. All five crew members survived.
• On August 31, 1986, Aeromexico Flight 498 collided in mid-air with a Piper Cherokee over the city of Cerritos, California, then crashed into the city, killing all 67 aboard the aircraft, 15 people on the ground, and all 3 in the small plane.
• On 3 December 1990, Northwest Airlines Flight 1482 went on the wrong taxiway in dense fog at Detroit-Metropolitan Wayne County Airport, MI (DTW). It entered the active runway instead of taxiway instructed by ATC. It collided with a Northwest B727 on take off. Nine people were killed.
• On July 2, 1994, USAir Flight 1016 crashed in Charlotte, North Carolina while performing a go-around because of heavy storms and wind shear at the approach of runway 18R. There were 37 fatalities and 15 injured among the passengers and crew. Although the airplane came to rest in a residential area with the tail section striking a house, there were no fatalities or injuries on the ground.
• On May 11, 1996 ValuJet Flight 592 crashed in the Florida Everglades due to a fire caused by the activation of chemical oxygen generators illegally stored in the hold. The fire damaged the plane's electrical system and eventually overcame the crew, resulting in the deaths of 110 people.
• In October 1997 Austral Flight 2553, DC-9-32, registration LV-WEG, en route from Posadas to Buenos Aires, crashed near Fray Bentos, Uruguay.
• On February 2, 1998 Cebu Pacific Flight 387 crashed on the slopes of Mount Sumagaya in Misamis Oriental, Philippines, killing all 104 people on board. Aviation investigators deemed the incident to be caused by pilot error when the plane made a non-regular stopover to Tacloban. Flight 387 was supposed to be a direct flight but due to the stopover, the pilots were not familiar with the route.
• On April 15 2008, a Hewa Bora Airways DC-9 crashed into a residential neighborhood, in the Goma, Democratic Republic of the Congo, resulting in death of at least 44 people.

Specifications

• Cabin cross section:
• External width: 10 ft 11.6 in (3.34 m)
• Internal width: 10 ft 3.7 in (3.14 m)
• External height: 11 ft 8 in (3.6 m)
• Internal height: 6 ft 9 in (2.06 m)

Official McDonnell Douglas DC-9 data.

See also

References

• Becher, Thomas. Douglas Twinjets, DC-9, MD-80, MD-90 and Boeing 717. The Crowood Press, 2002. ISBN 1-86126-446-1.

External links

• DC-9 page on Boeing.com
• DC-9 history page on Boeing.com
• DC-9-10/20/30 on Airliners.net and DC-9-40/50 on Airliners.net
• DC-9 History on AviationHistoryOnline.com
• Airliners Historical Overviews/Aircraft Specifications/Crash Statistics