Computer Simulation of Accelerate-Stop Distance Calculation

Analysis of aviation accidents and serious incidents in civil aviation shows that an aircraft exiting the runway and the terminal safety strip when the takeoff is aborted does not happen often, but is extremely dangerous. If the cause of the aborted takeoff (for example, engine failure) is detected before reaching "takeoff decision speed", then the aircraft usually has time to stop within the aerodrome. However, as the analysis of emergency situations shows, the real accelerate-stop distance (the length of the deceleration section until the aircraft stops completely) may differ from the value calculated in advance. Therefore, a more precise real time calculation of the accelerate-stop distance can help the crew make a more accurate and safer "go minus; no go" decision. The article continues the study of the previous work of the authors. The proposed algorithm uses piecewise constant interpolation of not only thrust, as in the previous work, but also other aircraft parameters. With this interpolation, the Riccati equation of the aircraft motion has explicit solutions. Besides using known interpolation time intervals, the time to reach a given speed is explicitly calculated, since some parameters change abruptly on reaching a certain speed. To check and study the proposed algorithm for estimating the accelerate-stop distance in real time, a computer simulation system was created. This system was used to compare the estimate of the accelerate-stop distance obtained using the proposed algorithm with the distance calculated on the basis of the full motion model by numerical integration. To confirm the adequacy of the algorithm, the simulation results were compared with the values obtained from the nomograms of a real aircraft. The proposed algorithm, after specifying a number of parameters, can be used in real conditions of an aborted takeoff.