Wide-body aircraft

A wide-body aircraft, also known as a twin-aisle aircraft and in the largest cases as a jumbo jet, is an airliner with a fuselage wide enough to accommodate two passenger aisles with seven or more seats abreast. The typical fuselage diameter is 5 to 6 m (16 to 20 ft). In the typical wide-body economy cabin, passengers are seated seven to ten abreast, allowing a total capacity of 200 to 850 passengers. Seven-abreast aircraft typically seat 160 to 260 passengers, eight-abreast 250 to 380, nine- and ten-abreast 350 to 480. The largest wide-body aircraft are over 6 m (20 ft) wide, and can accommodate up to eleven passengers abreast in high-density configurations.

By comparison, a typical narrow-body aircraft has a diameter of 3 to 4 m (10 to 13 ft), with a single aisle, and seats between two and six people abreast.

Wide-body aircraft were originally designed for a combination of efficiency and passenger comfort and to increase the amount of cargo space. However, airlines quickly gave in to economic factors, and reduced the extra passenger space in order to insert more seats and increase revenue and profits. Wide-body aircraft are also used by commercial cargo airlines, along with other specialized uses.

By the end of 2017, nearly 8,800 wide-body airplanes had been delivered since 1969, with production peaking at 412 in 2015.

Following the success of the Boeing 707 and Douglas DC-8 in the late 1950s and early 1960s, airlines began seeking larger aircraft to meet the rising global demand for air travel. Engineers were faced with many challenges as airlines demanded more passenger seats per aircraft, longer ranges and lower operating costs.

Early jet aircraft such as the 707 and DC-8 seated passengers along either side of a single aisle, with no more than six seats per row. Larger aircraft would have to be longer, higher (double-deck aircraft), or wider in order to accommodate a greater number of passenger seats.

Engineers realized having two decks created difficulties in meeting emergency evacuation regulations with the technology available at that time. During the 1960s, it was also believed that supersonic airliners would succeed larger, slower planes. Thus, it was believed that most subsonic aircraft would become obsolete for passenger travel and would be eventually converted to freighters. As a result, airline manufacturers opted for a wider fuselage rather than a taller one (the 747, and eventually the McDonnell Douglas DC-10 and Lockheed L-1011 TriStar). By adding a second aisle, the wider aircraft could accommodate as many as 10 seats across, but could also be easily converted to a freighter and carry two eight-by-eight freight pallets abreast.

The engineers also opted for creating "stretched" versions of the DC-8 (61, 62 and 63 models), as well as longer versions of Boeing's 707 (-320B and 320C models) and 727 (-200 model); and Douglas' DC-9 (-30, -40, and -50 models), all of which were capable of accommodating more seats than their shorter predecessor versions.