Flight simulations using time control with different levels of flight guidance

4D-trajectory-based operations are proposed by SESAR and NextGen as fundamental cornerstones of Air Traffic Management (ATM) system improvements of the future. An airborne Required Time of Arrival (RTA) function is seen as an initial enabler to allow better and more accurate planning of aircraft arriving, for example, at airspace sector boundaries or at the entry of a Terminal Area (TMA). Today, not all aircraft are equipped with RTA. In addition, aircraft have varying FMS trajectory prediction performances, varying levels of flight guidance functions (for example VNAV) and some aircraft do not have auto-thrust. All these factors may have an impact on the ability of an aircraft to fly a trajectory with a time constraint. To assess the feasibility of implementing arrival time control in an existing aircraft without excessive hardware modifications, an experimental FMS with RTA capability was developed and coupled to an existing Airbus A330 flight simulator at the scientific research facility of the Berlin Institute of Technology. A series of flight simulations was performed, using the RTA function in combination with different vertical profiles and different levels of flight guidance and automation. Some flights were flown using manual pitch control and without auto-thrust. Nearly all flights achieved an arrival time error of less than 10 seconds. Minimum flight guidance requirements were identified as an indication of the required calibrated airspeed (CAS) in the primary field of view of the pilot and an indication of the deviation from the reference vertical profile (VDEV). Finally a new RTA algorithm was designed to reduce the magnitude of the speed variations and was tested by means of fast-time simulation.