A flight management system (FMS) is a fundamental component of a modern airliner's avionics. An FMS is a specialized computer system that automates a wide variety of in-flight tasks, reducing the workload on the flight crew to the point that modern civilian aircraft no longer carry flight engineers or navigators. A primary function is in-flight management of the flight plan. Using various sensors (such as GPS and INS often backed up by radio navigation) to determine the aircraft's position, the FMS can guide the aircraft along the flight plan. From the cockpit, the FMS is normally controlled through a Control Display Unit (CDU) which incorporates a small screen and keyboard or touchscreen. The FMS sends the flight plan for display to the Electronic Flight Instrument System (EFIS), Navigation Display (ND), or Multifunction Display (MFD). The FMS can be summarised as being a dual system consisting of the Flight Management Computer (FMC), CDU and a cross talk bus.
FMS (Flight Management System) Honeywell on Boeing 767–300
A flight engineer (FE), also sometimes called an air engineer, is the member of an aircraft's flight crew who monitors and operates its complex aircraft systems. In the early era of aviation, the position was sometimes referred to as the "air mechanic". Flight engineers can still be found on some larger fixed-wing airplanes and helicopters. A similar crew position exists on some spacecraft. In most modern aircraft, their complex systems are both monitored and adjusted by electronic microprocessors and computers, resulting in the elimination of the flight engineer's position.
A flight engineer on an Avro Lancaster checks settings on the control panel from the fold down seat he used for take off in the cockpit
The cockpit of a non-operational four-engine Ilyushin Il-86, with its flight engineer's station at right