Survey of the flight efficiency of a long-haul aircraft under uncertainty of tasks

The article considers the problem of optimizing a long-haul aircraft flight under uncertainty of objectives and tasks. Based on the analysis of the well-known flight mode selection criterion, two main objectives of the flight were identified – minimizing fuel consumption and flight endurance. The study of this criterion based on a multi-purpose approach made it possible to develop an analytical model of the performance indicator containing two objective functions and a weight coefficient as a measure of comparative importance between the identified objectives. It is shown that the weight coefficient in the tasks of flight efficiency research is a measure of the uncertainty of the tasks. Consideration of the weight coefficient role in the optimization problem objective function made it possible to develop operational and trajectory methods for selecting flight modes. In the developed statement of the problem, the problems of cruise flight optimization and climb and descent modes are considered. The paper introduces the concept of the optimal cruise range as a vertical separation criterion, which allows you to rationally design the flight path at different flight levels under the uncertainty of tasks. The procedure for researching the efficiency and optimization of flight has been conducted and demonstrated by the method of mathematical modeling. The results of optimizing the flight mode are compared with the typical flight modes recommended by the flight manual. The introduced methods of flight efficiency investigation can be helpful in developing recommendations of long-haul aircraft operation. The methods and principles of a multi-purpose approach, operations research and decision theory were used in the paper. The long-haul aircraft IL-96-300 was selected as the object of research.