Boeing 747

The Boeing 747 is an American wide-body commercial jet airliner and cargo aircraft, often referred to by its original nickname, "Jumbo Jet". Its distinctive "hump" upper deck along the forward part of the aircraft makes it among the world's most recognizable aircraft, and it was the first wide-body produced. Manufactured by Boeing's Commercial Airplane unit in the United States, the original version of the 747 was envisioned to have 150 percent greater capacity than the Boeing 707, one of the common large commercial aircraft of the 1960s. First flown commercially in 1970, the 747 held the passenger capacity record for 37 years.

The four-engine 747 uses a double-deck configuration for part of its length. It is available in passenger, freighter and other versions. Boeing designed the 747's hump-like upper deck to serve as a first class lounge or extra seating, and to allow the aircraft to be easily converted to a cargo carrier by removing seats and installing a front cargo door. Boeing did so because the company expected supersonic airliners (development of which was announced in the early 1960s) to render the 747 and other subsonic airliners obsolete, while the demand for subsonic cargo aircraft would be robust well into the future. The 747 was expected to become obsolete after 400 were sold, but it exceeded critics' expectations with production passing the 1,000 mark in 1993. By September 2017, 1,536 aircraft had been built, with 17 of the 747-8 variants remaining on order. As of January 2017, the 747 has been involved in 60 hull losses, resulting in 3,722 fatalities.

The 747-400, the most common passenger version in service, has a high-subsonic cruise speed of Mach 0.85–0.855 (up to 570 mph or 920 km/h) with an intercontinental range of 7,260 nautical miles (8,350 statute miles or 13,450 km). The 747-400 passenger version can accommodate 416 passengers in a typical three-class layout, 524 passengers in a typical two-class layout, or 660 passengers in a high density one-class configuration. The newest version of the aircraft, the 747-8, is in production and received certification in 2011. Deliveries of the 747-8F freighter version began in October 2011; deliveries of the 747-8I passenger version began in May 2012.

The 747 has been involved in 146 aviation accidents and incidents, including 61 accidents and hull losses which resulted in 3722 fatalities. The last crash was Turkish Airlines Flight 6491 in January 2017. There was also 24 deaths in 32 aircraft hijackings, such as Pan Am Flight 73 where a Boeing 747-121 was hijacked by four terrorists and resulted in 20 deaths.

Few crashes have been attributed to design flaws of the 747. The Tenerife airport disaster resulted from pilot error and communications failure, while the Japan Airlines Flight 123 and China Airlines Flight 611 crashes stemmed from improper aircraft repair. United Airlines Flight 811, which suffered an explosive decompression mid-flight on February 24, 1989, led the National Transportation Safety Board (NTSB) to issue a recommendation that 747-200 cargo doors similar to those on the Flight 811 aircraft be modified. Korean Air Lines Flight 007 was shot down by a Soviet fighter aircraft in 1983 after it had strayed into Soviet territory, causing U.S. President Ronald Reagan to authorize the then-strictly military global positioning system (GPS) for civilian use.

Accidents due to design deficiencies included TWA Flight 800, where a 747-100 exploded in mid-air on July 17, 1996, probably due to sparking electricity wires inside the fuel tank; this finding led the FAA to propose a rule requiring installation of an inerting system in the center fuel tank of most large aircraft that was adopted in July 2008, after years of research into solutions. At the time, the new safety system was expected to cost US$100,000 to $450,000 per aircraft and weigh approximately 200 pounds (91 kg). El Al Flight 1862 crashed after the fuse pins for an engine broke off shortly after take-off due to metal fatigue. Instead of dropping away from the wing, the engine knocked off the adjacent engine and damaged the wing.

Attribution: Wikipedia ( https://en.wikipedia.org/wiki/Boeing_737 ) Content under Creative Commons Attribution-ShareAlike 3.0 Unported License