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. As of May 23, 2006, with the final two deliveries of the 717, production of the DC-9 aircraft family has ceased after 41 years.

Design and development
Douglas launched the DC-9 development project in April 1963, intending the DC-9 as a short-range companion to their larger four engined DC-8. Unlike the competing but slightly larger Boeing 727, which used as many 707 components as possible, the DC-9 was an all-new design. The DC-9 features two rear fuselage-mounted Pratt & Whitney JT8D turbofan engines, small, highly efficient wings, and a T-tail. In most configurations, DC-9 aircraft have distinctive 5-abreast seating in coach class. The airplane seats 80 to 135 passengers depending on version and seating arrangement.

The DC-9 prototype first 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 -10 variant would be followed by subsequent growth variants. The final DC-9 variant was the -50, which first flew in 1974. The DC-9 would be a commercial success with 976 built when the production ended in 1982.

The DC-9 would be followed by the introduction of the MD-80 series in 1980. The MD-80 series was originally called DC-9-80 series and was a lengthened DC-9-50 with a higher maximum take-off weight (MTOW) and higher fuel capacity. The MD-80 series was then developed into the MD-90 in the early 1990s. The last variant of the 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 DC-9 is one of the longest-lasting aircraft in operation. Northwest Airlines still operates a fleet of DC-9 aircraft, most of which are over 30 years old. The DC-9's reputation for reliability and efficiency drove strong sales 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.

Successors
The DC-9 was followed by the stretched and updated variants McDonnell Douglas MD-80 and MD-90. The MD-80 series features Pratt & Whitney JT8D engines with a higher thrust rating than those found on the DC-9, while the MD-90 features a glass cockpit, first featured on the MD-88 and new high-bypass International Aero V2500 engines. The MD-80 series was originally called the DC-9-80 and DC-9 Super 80 but the MD naming configuration was adopted in the early 1980s.

Variants

DC-9-10: The earliest and smallest DC-9 was 104.4 feet (31.8 m) long and had a maximum weight of 41 tonnes. Power was a pair of 14,000 lbf (54.5 kN) Pratt & Whitney JT8D-5s. A total of 137 were built. In August 2006 a total of 46 DC-9-10 aircraft remain in airline service. Major operators include USA Jet Airways (9). Some 12 other airlines operate smaller numbers of the type.

DC-9-15 and DC-9-20: These were variations on the -10 theme. The -15 added more fuel capacity and higher weights. The -20 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 delivered to Scandinavian Airlines, and only a small number of the -15 were made. As of October 2007, one DC-9-21 operates as a skydiving jump platform at Perris Valley Airport in Perris, CA (USA). With the steps on the rear airstair removed, it is the only airline transport class jet certified by the FAA for skydiving operations. 1Time in South Africa still operates a -15.

DC-9-30: The -30 was the definitive model with 662 produced, accounting for about 60% of production. The -30 entered service 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 a high-lift wing system of leading edge slats gives the Series 30 excellent short-field performance. Gross take-off weight was increased to 110,000 lb (50,000 kg), and P&W JT8D-9A engines rated at 14,500 lbf (65 kN) of thrust to JT8D-11 rated at 15,500 lbf (69 kN) of thrust. In December 2007, a total of 261 DC-9-30 aircraft are in airline service. Major operators include: ABX Air (43), Aero California (13), Aserca Airlines (20) and Northwest Airlines (57). Some 26 other airlines also still operate the type.

DC-9-40: This further stretched 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 a variety of Pratt & Whitney engines of between 64.5 and 71 kN. Seventy-one were produced. In December 2007, a total of 41 DC-9-40 aircraft are in airline service, with ABX Air (29) and Northwest Airlines (12).

DC-9-50: The -50 was the largest DC-9 to fly. It had an 8 ft 2 in (2.5) m fuselage stretch and seats up to 139 passengers. It started revenue service in August 1975 and, aside from the size increase, included a number of detail improvements, a new cabin interior, and quieter JT8D-15 or -17 engines in the 70 kN class. McDonnell Douglas delivered 96. In December 2007 a total of 40 DC-9-50 aircraft are in airline service, with Antrak Air (1), Hewa Bora Airways (1), Aeropostal Alas de Venezuela (2), Northwest Airlines (34) and Tikal Airlines (2).[citation needed] Some visual cues to distinguish this version with other DC-9 variants include side strakes (fins) below the side cockpit windows that are only found in the -50 and the engines are mounted differently so that the reverse thrusters appear higher than the center position found in the other models.

Military and government

C-9: Several -30 (with side cargo door) types were utilized by the US Military in C-9A Nightingale medevac configuration for the U.S Air Force and the C-9B Skytrain II version used by the U.S Navy and Marines for fleet logistics support moving both personnel and 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.

Incidents and accidents

"Airliners Historical Overviews/Aircraft Specifications/Crash Statistics" contains a list of DC-9 hull losses.

Notable incidents

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 due to mechanical failures. The crash killed all 101 passengers and crew.

On November 14, 1970, a Southern Airways Flight 932 DC-9 crashed into a hill near Tri-State Airport, Huntington, West Virginia. All 75 on board were killed (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 only survivor was a flight attendant, Vesna Vulovi?, 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 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 June 26, 1978, a DC-9 carrying Air Canada Flight 189 overran the runway in Toronto after a blown tire aborted the takeoff. 2 of 107 passengers and crew were killed.

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 June 2, 1983, a DC-9 carrying Air Canada Flight 797 had 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 country 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.

ValuJet Flight 592 crashed in the Florida Everglades on May 11, 1996 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.

Austral Flight 2553, DC-9-32, registration LV-WEG, en route from Posadas to Buenos Aires, in October 1997, crashed near Fray Bentos, Uruguay.

Cebu Pacific Flight 387 crashed on the slopes of Mount Sumagaya in Misamis Oriental, Philippines, on February 2, 1998 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.

A Northwest Airlines DC-9 went off the runway on January 21, 2007 at General Mitchell International Airport in Milwaukee. The accident was due to an explosion in one of the engines, forcing the pilot to abort takeoff. Of the 104 people aboard, only one back injury was reported.

On May 18, 2007, a Northwest Airlines DC-9, after departing from Syracuse Hancock International Airport at 12pm en route to Detroit Metropolitan Airport, had to make an emergency landing at Buffalo-Niagara International Airport after pilots reported pressure loss and smoke in the cabin around 1:15pm. Once the plane got to a gate, they found a 12-inch (300 mm) gash in the front of the fuselage, near rows 1 and 2. None of the 95 passengers or 4 crew members were injured.