Announced at the Asian Aerospace 2002 show in Singapore and supposed to enter service in 2004. The development of the plane was abandoned and effort was put into the 747-8.
Following the termination of the 747X program, Boeing continued to study improvements which could be made to the aircraft. The 747-400XQLR (Quiet Long Range) would have featured longer range than the 747-400ER, at 7980 nm (14,800 km), along with improvements to improve efficiency and reduce noise.
The "X" in the title signified it as a variation of the 747-400. In order to make the new 747 more environmentally friendly, the engines were given new acoustic liners and were equipped with "chevron" shaped cowlings around the fan and core exhausts. The result was a 20% reduction in what is know as "noise area level" on takeoff and a decrease of 40% on landing as compared to the standard 400.
Other improvements included extra fuel storage in the horizontal tail tank and a gross weight increase from 910,000 pounds to 921,000. The QLR also spotted raked wingtips similar to those on the extended range 777 and the 767-400ER.
While the 747-400XQLR did not move to production, many features were picked up for the 747 Advanced, which has now been launched as the 747-8.