Douglas DC-9-40

The Douglas DC‑9‑40 is a stretched variant of the popular DC‑9 series produced by the Douglas Aircraft Company, later McDonnell Douglas, between 1969 and 1980. Building on the original 1965 DC‑9 design, the -40 incorporated a lengthened fuselage that added 10.5 feet, allowing seating for up to 115 passengers in a single‑aisle configuration. Powered by two rear‑mounted Pratt & Whitney JT8D low‑bypass turbofan engines, the aircraft delivered reliable thrust while maintaining a compact footprint suitable for short‑ and medium‑range routes. The -40 introduced upgraded avionics, a higher‑capacity fuel system, and improved cabin comfort, including wider seats and larger overhead bins. Over 500 units were delivered to airlines worldwide, from major carriers such as United, Delta, and Alitalia to regional operators in Asia and South America. The model’s operational efficiency, quick turnaround times, and ability to operate from relatively short runways helped airlines expand point‑to‑point services, shaping the hub‑and‑spoke network that dominates modern air travel. Though eventually superseded by the MD‑80 series, the DC‑9‑40 remains a pivotal step in the evolution of narrow‑body jetliners, influencing design philosophies still evident in today’s commercial aircraft.

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