Research On Safety Assessment Of Civilaircraft Fuel System

"Civil aircraft development,safety first".In the development process of civil aircraft,safety has always been a top-level requirement.Therefore,the safety assessment ability to ensure the safety requirements of civil aircraft has become particularly important.Only by improving the safety of civil aircraft Level,China's large domestic aircraft can gain competitiveness in the international civil aircraft market.As an important part of civil aircraft,the fuel system plays an important role in the safe flight of civil aircraft,because the fuel system not only undertakes the task of supplying fuel to the civil aircraft engine,but also is closely connected with most systems of civil aircraft.The safety assessment of civil aircraft fuel system is extremely important.In order to improve the safety of the civil aircraft fuel system during its design phase and reduce the risk during its operation phase,based on various airworthiness clauses and guidelines related to civil aircraft system safety assessment processes and methods,this article reviews the safety assessment processes and methods for the entire life cycle of civil aircrafts from research and development and design to operation and maintenance.In the design stage,a dynamic fault tree analysis method based on fuzzy Markov is studied.In the operation stage,the risk assessment method based on TARAM is optimized.The quantitative assessment of the safety and risk of the fuel system of civil aircraft is performed.The main work of this article is as follows:(1)From the perspective of airworthiness,the basic theory of the safety evaluation of civil aircraft fuel system is studied.Combining with the policies and guidelines issued by various countries(such as SAE ARP4761 and SAE ARP5150 A,etc.),the safety evaluation process of initial airworthiness phase and the risk assessment process of the continuous airworthiness phase of civil aircraft were reviewed.And various applicable methods have been studied.(2)In the initial airworthiness phase,based on the fault tree analysis of the safety evaluation method,combined with Markov model and fuzzy set theory,the safetyevaluation method of dynamic fault tree based on fuzzy Markov model was studied.The calculation method of the minimum cut set and the calculation method of the failure probability were optimized.In the continuous airworthiness phase,based on the risk assessment method TARAM,combined with the three-parameter Weibull distribution and logical decision method,the TARAM was optimized,and the calculation of the probability of failure was more accurate and objective,avoiding the subjective disadvantage.(3)In the continuous airworthiness phase,a calculation analysis was performed in combination with the failure example of the fuel system "loss of fuel supply to the left engine".The minimum cut set of the static subtree and the fuzzy failure probability of the dynamic subtree are solved.In the continuous airworthiness phase,analytical calculations are performed in conjunction with the fuel system failure example "fuel pipe leakage",calculate the risk value R by determining the values of several parameters respectively.