Editing Boeing 747 (section)

==== 747-500X, -600X, and -700X ====
[[File:Boeing 747-500X and 747-600X comparison line drawing.jpg|thumb|The proposed 747-500X and -600X as depicted in a 1998 [[Federal Aviation Administration|FAA]] illustration|alt=Aircraft comparison diagram.]]

Boeing announced the 747-500X and -600X at the 1996 [[Farnborough Airshow]].<ref name="boe_1996" /> The proposed models would have combined the 747's fuselage with a new wing spanning {{Convert|251|ft|m|abbr=out}} derived from the 777. Other changes included adding more powerful engines and increasing the number of tires from two to four on the nose landing gear and from 16 to 20 on the main landing gear.<ref name="faa_nla">Patterson, James W. [http://www.tc.faa.gov/its/worldpac/techrpt/ar97-26.pdf "Impact of New Large Aircraft on Airport Design (PDF)"]. ''[[Federal Aviation Administration]]'', March 1998. Retrieved: December 17, 2007.</ref>

The 747-500X concept featured a fuselage length increased by {{Convert|18|ft|m|abbr=out}} to {{Convert|250|ft|m|abbr=out}}, and the aircraft was to carry 462 passengers over a range up to {{Convert|8700|nmi|abbr=out}}, with a gross weight of over 1.0&nbsp;[[Mega-|Mlb]] (450&nbsp;tonnes).<ref name="faa_nla" /> The 747-600X concept featured a greater stretch to {{Convert|279|ft|m|abbr=out}} with seating for 548 passengers, a range of up to {{Convert|7700|nmi|abbr=on}}, and a gross weight of 1.2&nbsp;Mlb (540&nbsp;tonnes).<ref name="faa_nla" /> A third study concept, the 747-700X, would have combined the wing of the 747-600X with a widened fuselage, allowing it to carry 650 passengers over the same range as a {{not a typo|747-400}}.<ref name="boe_1996" /> The cost of the changes from previous 747 models, in particular the new wing for the 747-500X and -600X, was estimated to be more than US$5&nbsp;billion.<ref name="boe_1996" /> Boeing was not able to attract enough interest to launch the aircraft.<ref name="FI_500X" />