The adverse impact of flight management systems on long range international airline operations

United Airlines began using Flight Management Systems (FMS) in 1982. The FMS-equipped aircraft operated initially in the domestic environment. Eventually, FMS-equipped aircraft operated on very long segments, such as Los Angeles to Hong Kong, which often required operation of the aircraft at multiple limits such as maximum takeoff weight, maximum fuel capacity, and/or specified fuel reserves. These limits are not fully considered by the current generation FMS in attempting to optimize the speed schedule. Software enhancements to this speed schedule logic could bring economic benefits to airlines flying these operationally challenging flights