Navinda Kithmal Wickramasinghe

Flight Trajectory Optimization for Modern Jet Passenger Aircraft with Dynamic Programming

Future Air Transportation Systems (ATS) would eventually have to treat the ever increasing demands in aviation industry. Fuel consumption and flight time could be significantly reduced by modifying the current sector based system into a more relaxed user priority based ATS. Trajectory Based Operations (TBO) is considered as one of the key technologies in this transition. This paper concentrates on a proposed flight trajectory optimization tool based on Dynamic Programming (DP), meteorological data and an aircraft performance model to obtain fuel minimum 4D-optimal flight trajectories for a single jet passenger aircraft considering the effect of wind conditions. Major drawbacks such as “Curse of Dimensionality” in DP are overcome with a unique method called “Moving Search space Dynamic Programming (MS-DP)” method. A quantitative evaluation has revealed that an average reduction of 9% in fuel consumption could be achieved with a tradeoff of flight time which exceeds at an average of 7% compared to a series of flight data measured by a commercial GPS receiver in an airliner cabin.

Correlation between flight time and fuel consumption in airliner flight plan with trajectory optimization

Present day airliners are compelled to operate with efficient flight plans to meet the ever increasing demands and cope with high fuel prices while sustaining a profitable industry. On the contrary, passenger airplane consume excessive fuel and flight time due to conventional air traffic control procedures. This paper provides an in-depth evaluation on the correlation between flight time and fuel consumption by referring to potential benefits obtained via dynamic programming trajectory optimization. Analytical solutions on the selection of an optimal cost index based on a series of flight data measured by a commercial GPS receiver are thoroughly discussed. Performance parameters were evaluated using meteorological data of the Japan Meteorological Agency and aircraft performance data of EUROCONTROL. Analytical results show that the selection of descent airspeed and descent rate have a significant influence on reducing the fuel consumption and flight time. Optimal cost index selection was discussed by implementing fuel minimum trajectories and fuel optimal trajectories with arrival time constraints. Analytical results from the proposed model show that current operational procedures let airliners to perform with non-optimal cost indexes to maintain time weighted flight missions which result excessive fuel burn.

Analyzing Feasibility of Continuous Descent Operation Following Fixed-flight Path Angle from Oceanic Route to Tokyo International Airport

Improving trajectory predictability during Continuous Descent Operation (CDO), one of the ideas suggested in this paper applies “Fixed-flight Path Angle (FPA) descent”, with which the arrival aircraft perform continuous descent following the assigned flight path angles. The FPA descent is expected not only to save fuel, but also contribute to high performance arrival management, eventually leading to efficient departure scheduling and capacity management of runways and airspaces close to the airport. This paper discusses the applications of FPA descent to large commercial jet aircraft. The FPA descent is evaluated via two types of simulators: one is a B777-200 full-flight simulator owned by a national airline company, and the other is an air traffic simulator which demonstrates arrival traffic flow to Tokyo International Airport. Series of flight simulator experiments were carried out to assess the pilot’s operability during the FPA descent from oceanic air route. Aircraft tracking performance on the assigned FPA vertical path is confirmed via the flight simulator experiments. Fuel consumption of the FPA descent is compared with that of Optimal Profile Descent (OPD). Monte Carlo simulations were used to evaluate time-spacing performance of the FPA descent in arrival traffic via air traffic simulator. How the combination of FPA descent and automatic speed control in airborne, Flight-deck Interval Management (FIM), works for arrival time-spacing is clarified through the series of air traffic simulations. These simulation results show the applicability of the proposed FPA descent and suggest future contributions towards efficient arrival operations.

Evaluating Energy-Saving Arrivals of Wide-Body Passenger Aircraft via Flight-Simulator Experiments

This study evaluates energy-saving arrival operations based on a series of experiments using B777-200 and B787-8 full-flight simulators. A total of 50 trials were carried out to simulate arrivals at two major international airports located at the metroplex area in Japan: the Tokyo and Kansai International Airports. This paper proposes applying fixed-flight path-angle descent—in which the aircraft descends continuously, following a defined vertical path—as a potential solution for both arrival-time management and fuel-efficiency enhancement. The proposed type of descent improves the predictability of the arrival aircraft trajectory on the ground, and therefore, supports the air traffic controllers’ task of maintaining safe separations within the air traffic flows in both en route and terminal areas. The operational feasibility of the proposed method under nominal and nonnominal situations is studied, considering the pilots’ operation of the flight management system, and the operators’ benefits—through fuel...

Optimization-Based Performance Assessment on 4D Trajectory-Based Operations with Track Data

The enhancement of air traffic management (ATM) system performance by management of aircraft trajectories, commonly referred to as 4D trajectory-based operations (TBO), is one of the key technologies in the Japan Civil Aviation Bureau’s “Collaborative Actions for Renovation of Air Traffic Systems (CARATS)” plan. The release of “CARATS Open Data,” aircraft track data for all scheduled commercial instrument rule flights in Japan’s en route airspace, has enabled the understanding of performance in present flight operations on a broad scale and assesses the potency of possible benefits toward a futuristic ATM system. This paper focuses on potential benefits in a 4D TBO system through operational performance on existing flight operations based on trajectory optimization. A trajectory optimization model developed by the authors is used to investigate the potential benefits by exerting the maximum performance of the aircraft in respect to highly regulated restrictions used in current flight procedures. Quantitative results show that weather conditions have a significant impact on conventional operational performance. Optimized results denote that substantial benefits could be obtained by more relaxed flight planning which vary according to arrival time assignment and weather conditions.

Arrival Time Assignment by Dynamic Programming Optimization

Japanese airspace capacity must expand in order to accommodate the increased air traffic expected in the near future. Efficient air congestion management is a promising approach for achieving this goal. Arrival management for inbound flights to Tokyo International Airport, the busiest airport in Japan, is considered to be the most demanding challenge for efficient air congestion management. In this paper, a concept of arrival management based on multiple aircraft trajectory optimization is proposed and examined using the actual flight track data. At first, free-flight trajectory optimization is applied to the inbound flights landing on one of the two runways to simulate the most efficient ideal flights. Next, time separation constraints at a merging point on the boundary of the terminal area are imposed in order to avoid conflicts among the aircraft in the terminal area. As a result of the optimization, optimal sequencing and flight time adjustments are generated. Benefits of the proposed concept are evaluated by comparing the optimal trajectories with the corresponding actual flight trajectories. Dynamic programming is used for the optimization of each flight trajectory and scheduling of the arrival times. The obtained results reveal that in addition to safe arrival time separation, trajectory optimization with arrival time assignment produces substantial benefits in terms of fuel consumption and flight time.