Dynamic Bayesian networks model for causal-time series coupling in aircraft takeoff attitude and flight operations
[Objective]During takeoff of civil aviation aircraft,pilot operational errors can easily lead to accidents,such as tail strikes.The aircraft takeoff attitude is closely related to flight operations.Therefore,focused on the decoupling problem between aircraft takeoff attitude and flight operations,guided by the"Safety Ⅱ"mode,the coupling mechanism between aircraft takeoff attitude and flight operations is studied.This investigation considers the risk response performance throughout the entire process of aircraft takeoff.[Methods]The research is based on the flight quick access recorder(QAR)data of a domestic airline's A319 fleet.A coupling model of aircraft takeoff attitude,flight operations,aircraft performance,and flight environment is established using dynamic Bayesian networks(DBN)and Genie software for parameter learning and modeling.Daily flight data are deeply explored and fully utilized to study the causal-time series coupling mechanism between flight operations and aircraft takeoff attitude.Initially,based on the theory of safety resilience,the causal-time series coupling(CTC)model is developed to analyze the aircraft takeoff attitude and flight operations.Then,based on the QAR data of 1 359 flight segments of a domestic airline's A319 fleet,the CTC-DBN model is quantified and validated using Genie software.Results show that the CTC-DBN model can effectively analyze the dynamic formation mechanism of aircraft takeoff attitude.Finally,single and combined scenarios,such as heavy load,light load,downwind,and headwind,are selected to determine the optimal flight operation mode by adjusting the probability distribution of key flight operation nodes.The coupling mechanism between aircraft takeoff attitude and flight operations under different scenarios is studied,ultimately improving the pilot's ability to respond to risks in advance.[Results]The results indicate that the model can effectively analyze the dynamic formation mechanism of aircraft takeoff attitude.(1)The difference in aircraft weight is mainly reflected in the different throttle commands in the moment of rotation and the varied pitch commands in the moment of takeoff.A relatively large weight of the aircraft indicates considerable throttle in the moment of rotation and rapid pitch command in the moment of takeoff to obtain sufficient lift for the aircraft.(2)The different wind directions are mainly manifested by varied throttle commands at three distinct moments.The throttle of the headwind scenario is greater than that of the tailwind scenario in all three instances,thereby overcoming the wind speed and obtaining sufficient airspeed to ultimately ensure sufficient lift for the aircraft.(3)Compared with the optimal flight operation modes of four single scenarios,the combination of two scenarios increases the throttle commands due to heavy weight and headwinds.The throttle command exhibits a decreasing trend owing to its small weight and downwind.The pitch command at the time of takeoff in various scenarios has immediately become the main mode.[Conclusions]The causal-time series coupling mechanism between flight operations and aircraft takeoff attitude is studied using the CTC-DBN model.This research ultimately provides guidance for pilot operations and improves the risk response ability of pilots during the aircraft takeoff process.Subsequent research should combine other data,such as terrain,meteorology,and pilot characteristics,to conduct in-depth studies on different types of takeoff and landing.
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