Boeing 747

The **Boeing 747** is a large, long-range wide-body jet airliner that was designed and manufactured by Boeing Commercial Airplanes in the United States between 1968 and 2023. After introducing the 707 in October 1958, Pan Am wanted a jet 2+1⁄2 times its size, to reduce its seat cost by 30%. In 1965, Joe Sutter left the 737 development program to design the 747, the first twin-aisle airliner. In April 1966, Pan Am ordered 25 Boeing 747-100 aircraft, and in late 1966, Pratt & Whitney agreed to develop the JT9D engine, a high-bypass turbofan. On September 30, 1968, the first 747 was rolled out of the custom-built Everett Plant, the world's largest building by volume. The first flight took place on February 9, 1969, and the 747 was certified in December of that year. It entered service with Pan Am on January 22, 1970. The 747 was the first airplane called a "**Jumbo Jet**" as the first wide-body airliner.

The 747 is a four-engined jet airliner, initially was powered by Pratt & Whitney JT9D engines, then General Electric CF6 and Rolls-Royce RB211 engines for the original variants. With a ten-abreast economy seating, it typically accommodates 366 passengers in 3 travel classes. It has a pronounced 37.5° wing sweep, allowing a Mach 0.85 (490 kn; 900 km/h) cruise speed, and its heavy weight is supported by four main landing gear legs, each with a four-wheel bogie. The partial double-deck aircraft was designed with a raised cockpit so it could be converted to a freighter airplane by installing a front cargo door, as it was initially thought that it would eventually be superseded by supersonic transports.

Boeing introduced the -200 in 1971, with more powerful engines for a heavier maximum takeoff weight (MTOW) of 833,000 pounds (378 t) from the initial 735,000 pounds (333 t), increasing the maximum range from 4,620 to 6,560 nautical miles [nmi] (8,560 to 12,150 km; 5,320 to 7,550 mi). It was shortened for the longer-range 747SP in 1976, and the 747-300 followed in 1983 with a stretched upper deck for up to 400 seats in three classes. The heavier 747-400 with improved RB211 and CF6 engines or the new PW4000 engine (the JT9D successor), and a two-crew glass cockpit, was introduced in 1989 and is the most common variant. After several studies, the stretched 747-8 was launched on November 14, 2005, with new General Electric GEnx engines, and was first delivered in October 2011. The 747 is the basis for several government and military variants, such as the VC-25 (Air Force One), E-4 Emergency Airborne Command Post, Shuttle Carrier Aircraft, and some experimental testbeds such as the YAL-1 and SOFIA airborne observatory.

## Shuttle Carrier Aircraft

The **Shuttle Carrier Aircraft** (**SCA**) are the two retired extensively modified Boeing 747 airliners that NASA used to transport Space Shuttle orbiters. One (N905NA) is a 747-100 model, while the other (N911NA) is a short range 747-100SR. It entered service in 1977 but then it was retired in 2012 after the Space Shuttle program came to an end after STS-135.

The SCAs were used to ferry Space Shuttles from landing sites back to the Shuttle Landing Facility at the Kennedy Space Center in Cape Canaveral, Florida. The orbiters were placed on top of the SCAs by Mate-Demate Devices, large gantry-like structures that hoisted the orbiters off the ground for post-flight servicing then mated them with the SCAs for ferry flights.

In approach and landing test flights conducted in 1977, the test shuttle *Enterprise* was released from an SCA during flight and glided to a landing under its own control.