Overview
Airports and terminal control areas are behaving as bottlenecks in the growth of capacity for air passenger and freight transport. Sequencing and metering tools provide air traffic controllers with the expected time of arrival of each incoming aircraft and the amount of delay to be absorbed by each aircraft to meet the landing schedule. However, these tools suffer from a lack of accurate 4-D aircraft performance models and meteorological models. An improvement is needed in the accuracy of the predicted flight path for the final phase of the flight, in order to enhance the accuracy of information on the time of aircraft landing.
The overall objective of ARAMIS was to adapt and develop models and tools for 4-D-planning, guidance and control, during the approach phase of flight, from initial approach fix until runway threshold. The project thus intended to produce efficient spacing between aircraft, and help to increase airport capacity by smoothing the controllers workload.
The specific objectives of ARAMIS were:
- to study the choice and the adaptation of the existing models in the field of procedures, aircraft performance and weather;
- to build an aircraft performance and weather model;
- to develop, test and evaluate a prototype, including an aircraft performance model, a weather model, a trajectory prediction, monitoring/guidance, a sequencer and the human/machine interface.
Funding
Results
The survey on the procedures recommended by the different airlines for the time period when the approach controller can exercise speed and flight-plan control over the aircraft, highlighted important differences in the policies of the airlines on descent speeds and point of stabilisation.
An inventory and classification of aircraft performance models was produced. The evaluations of two versions of aircraft performance models identified the parameters currently available in the aircraft performance database, Base of Aircraft Data (BADA), that needs more accurate assessment in view of their impacts on the time accuracy of the trajectory predictor. These parameters include, in particular, the aircraft mass at the initial approach fix and the aerodynamic parameters for non-clean configuration (i.e. using flaps, brakes and landing gear).
Simulations showed that the ARAMIS weather model can provide gridded nowcasts of winds, provided that an adequate source of observations become available, either from aircraft or from other sensors such as a network of strategically placed profilers.
The ARAMIS demonstrator supports computations of aircraft trajectories during the descent, and during the initial and final approach phases. Its central part is the trajectory predictor, which is triggered by the sequencing and the monitoring and guidance tool. A test of the system in a simulation environment identified the description of the descent profile and the information on mass and on when to change drag configuration as the main factors having an impact on time accuracy.
Suggestions on the guidance actions to be supplied by the system have been provided by a feedback from controllers. Advisory information should be displayed only when a deviation between the computed trajectory and the actual position occurs, and should indicate heading or speed information.
Policy implications
The ARAMIS project has demonstrated the technical feasibility of a ground-based controller aid for aircraft approach. A number of points remain to be studied, including the implementation on complex cases, of the function that computes a trajectory complying with a target time of arrival, and the improvement on the accuracy of the trajectory forecast function. The ARAMIS results provide valuable inputs for future research aimed at the integration of the various air traffic control segments: en-route, approach and airport.