McDonnell Douglas DC-9-40/50


Country of Origin
United States of America
Short to medium range airliners
The DC-9-40 and DC-9-50 are stretched developments of the DC-9-30 and predecessors to the later further lengthened MD-80 and MD-90 series. The DC-9-40 was developed in response to a Scandinavian Airlines System (SAS) requirement for a larger capacity development of the DC-9. Compared with the DC-9-30, the DC-9-40 is 1.88m (6ft 2in) longer, raising seating capacity in a single class configuration to 125. Apart from the fuselage stretch and more powerful engine options, the -40 was the much the same as the -30. First flight occurred on November 28 1967, and the -40 entered service with SAS on March 12 the following year. The DC-9-50 is the largest member of the DC-9/MD-80/MD-90/717 family to bear the DC-9 designation. Launched in mid 1973, the DC-9-50 is a further 2.44m (8ft 0in) longer than the DC-9-40, or 4.34m (14ft 3in) longer than the DC-9-30, and has maximum seating for 139 passengers. Delivered from August 1975, the DC-9-50 introduced a new look cabin interior designed to make more efficient use of the space available and give the impression of a more spacious interior, plus other improved features such as an improved anti skid braking system and quieter engines compared with the DC-9-40. The DC-9-40 and -50 sold only in fairly modest numbers before the arrival of the further stretched MD-80 series. The largest DC-9-40 customer was SAS, while Northwest continues to operate a large fleet of DC-9-40s and -50s (it is currently the largest DC-9 operator in the world).
40 - Two 64.5kN (14,500lb) Pratt & Whitney JT8D-9 turbofans, or two 66.7kN (15,000lb) JT8D-11, or two 69.0kN (15,500lb) JT8D-15s, or two 71.2kN (16,000lb) JT8D-17s. 50 - Two 69.0kN (15,500lb) JT8D-15s, or two 71.2kN (16,000lb) JT8D-17s.
40 - Max cruising speed 898km/h (485kt), long range cruising speed 820km/h (443kt). Range at high speed cruise with 70 passengers and reserves 1725km (930nm), range with 87 passengers and reserves at long range cruising speed 2880km (1555nm). 50 - Speeds same except for max speed 926km/h (500kt). Range at long range cruising speed with 97 passengers and reserves 3325km (1795nm).
40 - Empty 26,612kg (58,670lb), max takeoff 54,885kg (121,000lb). 50 - Empty 28,068kg (61,880lb), max takeoff 54,885kg (121,000lb).
40 - Wing span 28.47m (93ft 5in), length 38.28m (125ft 7in), height 8.53m (28ft 0in). Wing area 93.0m2 (1000.7sq ft). 50 - Same except for length 40.72m (133ft 7in).
Flightcrew of two. 40 - Seating for up to 125 passengers at five abreast. 50 - Seating up to 139 passengers at five abreast and 79cm (31in) pitch.
Total DC-9 production of 976, including 71 Series 40s and 96 Series 50s. Approximately 53 -40s and 46 -50s remained in service in late 2002.
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McDonnell Douglas DC-9-40/50
The backbone of this section is from the The International Directory of Civil Aircraft by Gerard Frawley and used with permission. To get your own copy of the book click here.