Research On Risk Assessment And Forecast In Exceeding Tire Speed Rating During Take-off Based On Operational Data

During take-off,due to the influence of its own performance,flight crew control and environmental,exceeding tire speed rating may be caused.Exceeding tire speed rating during take-off will cause tire damage or even tire blowout,seriously endangering flight safety.At present,the research on exceeding tire speed rating is mainly event-driven analysis,and lack of risk studies combining with data.Therefore,from the perspective of civil aviation risk management,the actual operation data is used to carry out research on the risk identification,evaluation and prediction of exceeding tire speed rating,so as to realize the risk threshold moving forward.The research mainly completes the following work:1.The influencing factors of exceeding tire speed rating are analyzed from 4 aspects of flight crew control,aircraft attitude,aircraft performance and environment.Then,correlation analysis and principal component analysis were used to quantitatively screen and finally determine 8 key parameters.2.Using the cloud model based on heuristic Gaussian cloud transformation and forward Gaussian cloud algorithm,discretize the risk index data to obtain discrete samples.The characterization parameter of exceeding tire speed rating risk,that is the lift off speed was input into the cloud model to achieve a soft classification of the risk into 2 levels.3.A risk assessment model of exceeding tire speed rating based on cloud Bayesian network was established.Through forward evaluation,the validity of the model is verified.Then,the main influencing factors of exceeding tire speed rating are obtained by backward diagnosis analysis.4.The risk prediction model of exceeding tire speed rating based on BP neural network optimized by genetic algorithm is established.Accuracy rate,precision rate,recall rate and F1 score evaluation indexes were used to evaluate the prediction model,and the prediction effects of the model before and after optimization were compared.The simulation results show that the key factors of exceeding tire speed rating during takeoff of A319 aircraft at Lhasa Gongga Airport are the large take-off weight,the downwind and the improper operation of the flight crew are important factors.Compared with BP neural network prediction model,each evaluation index value of the prediction model optimized by genetic algorithm reaches more than 90%,and the prediction effect is better.Through the above research,it provides a theoretical basis for relevant operators to take reasonable risk control measures of exceeding tire speed rating,which is helpful to ex ante management of risk of exceeding tire speed rating.