After the end of the 747X program, Boeing continued to study improvements that could be made to the 747. The 747-400XQLR (Quiet Long Range) was meant to have an increased range of , with improvements to boost efficiency and reduce noise."Boeing Offers New 747-400X Quiet Longer Range Jetliner." The Boeing Company, February 26, 2002. Retrieved: December 17, 2007."GE's CF6 Engine Models Tailored For Boeing's 747-400XQLR Wide-Body." GE Aviation, March 25, 2002. Improvements studied included raked wingtips similar to those used on the 767-400ER and a sawtooth engine nacelle for noise reduction.Steinke, Sebastian. "Boeing Proposes 747-400X Quiet Longer Range." Flug Revue Online, May 2002. Retrieved: July 15, 2011. Although the 747-400XQLR did not move to production, many of its features were used for the 747 Advanced, which was launched as the 747-8 in 2005.Kingsley-Jones, Max. "IN FOCUS: Boeing 747-8 technical description & cutaway". Flight Global, November 13, 2012.
