The Study On Causes Of General Aviation Flight Accidents In China

General aviation is an important part of civil aviation and plays a unique role in national economic and social development.However,at the present stages,the general aviation safety production in China is severe and serious accidents occur from time to time.The occurrence of general aviation accident is the result of a variety of factors or combinations thereof.Learning from accidents is an important means of accident prevention.However,the current lack of a comprehensive analysis of the causes of general aviation flight accidents is not conducive to proposing targeted prevention and control measures to effectively control the causes of general aviation flight accidents.Therefore,in order to comprehensively analyze the causes of general aviation flight accidents,the implementation of the effective prevention of general aviation flight accidents,this paper adopts literature review,comparative study,statistical analysis,case study analysis,Chi-square test,the Bootstrap since the combination of qualitative and quantitative methods.The macroscopic rule of 69 general aviation accident samples in China from 1995 to 2015 is studied.By comparing and analyzing 6 kinds of accident causes models,24Model is selected as the theoretical basis of the study.Based on the existing classification of 24Model and combined with the general aviation flight practice,the classification and analysis method of general aviation accident causes based on 24Model(24Model for general aviation,24Model-GA)is proposed.The 24Mode-GA constructed is used to comprehensively analyze the unsafe acts,unsafe conditions,indirect causes,deficiencies in safety management system,deficiencies in safety culture,deficiencies in external factors in 69 accidents mentioned above,therefore,a general aviation flight accident causes database is initially formed.Based on the 69 general aviation flight accident causes analysis results,for the purpose of effectively control these causes of the accidents,the four table Chi-square test is used to analyze the association relationships between adjacent two subcategories in 24Model-GA.The results can help the general aviation companies to clarify the control focus of accident prevention and try to put forward preventive control measures.The main conclusions obtained in this paper are as follows:(1)The macroscopic rule of general aviation flight accident is obtained from the time feature,accident grade,accident flight stage,accident occurrence area and the subordinate civil aviation regional administration,pilot age,accident aircraft models,operation types and their internal development and evolution laws.The results show that the high-frequency accident month are mainly concentrated in June and July.The accident within one day is mainly concentrated in the periods of 9:00-10:00 and 15:00-16:00.At the present stage,the major grade accident has been effectively controlled,but the general grade accident shows a rapid growth trend.The cruise/operation stage is the flight stage with high accident occurrence.Sichuan and Heilongjiang provinces have the highest accidents.The total number of accidents occurred in the administrative of southwest region is the highest,accounting for 20%of the total number of accidents.The average age of accident pilots is 43.7 years old,among which 45 to 65 years old account for 50%of the total population.The accident aircraft models of the top three,respectively is Y-5,MI-8,Robinson R44?.Aerial spraying and commercial driver's license training are the two types of operations with the highest frequency of accidents.The research results provide references for the prevention of general aviation accidents from macroscopic perspective.(2)The 24Model is improved and a 24Model-GA based on general aviation accident classification analysis method is constructed.The processes and steps of accident analysis are given.The proposed 24Model-GA contains 6 categories and 46 subcategories,the definitions of 46 subcategories is given.The analysis process of accident includes:taking general aviation company as the organization scope of accident analysis;the analysis scope of an accident includes unsafe acts,unsafe conditions,indirect causes,deficiencies in safety management system,deficiencies in safety culture,deficiencies in external factors.Taking the moment of aircraft crashed as the end point of accident analysis,this study makes it clear that the analysis of accident causes does not include the emergency rescue process.Analysis procedure of accident causes:directly extract the remarkable information in accident report;according to Why-Because method and causal sufficiency criterion reasonable inference the information which is not significant remarkable;detailed catalogue of accident causes;classify the detailed directory into 24Model-GA according to its definitions.(3)Using 24Model-GA and its definitions of unsafe acts,unsafe conditions,indirect causes,deficiencies in safety management system,deficiencies in safety culture,and deficiencies in external factors,a total of 1431 causes of 69 general aviation accidents are identified.The statistical causes are classified into each categories and subcategories of 24Model-GA and the rules of each categories and subcategories are obtained.? 250 unsafe acts are identified,including 34 kinds of forms.The results help General aviation companies clear about the need to focus on the control of 11 kinds of high-frequency unsafe acts and their definitions,they are:poor preflight preparation(24 times),poor operation technology(20 times),poor crew resource management(15 times),improper distribution of' attention(15 times),failure to monitor preflight preparations effectively(14 times),failure to take measures in time(13 times),violations and illegal organization and implementation work(12 times),improper staffing(11 times),violation flight plan(10 times),failure to organize training(10 times),failure to implement effective monitoring(10 times).By studying the influence path of unsafe acts,the results show that flight crew's unsafe acts mainly lead to accidents and other unsafe acts in organization.The maintenance personnel's unsafe acts mainly lead to unsafe conditions.The training director's unsafe act mainly leads to indirect causes.The operation director's unsafe act mainly leads to deficiencies in safety management system.The top management's unsafe acts mainly lead to deficiencies in safety culture.The results emphasize that the staff should realize the importance of unsafe acts' self-control.The identified unsafe acts are classified into categories and subcategories of 24Model-GA,it is concluded that 53.6%of unsafe act are violation operation.It is clarified that control poor preflight preparation,improper distribution of attention,violations and illegal organization and implementation work,violation flight plan can prevent 43.3%of violation operation.Furthermore,by classifying unsafe acts according to the types of operations,the high-frequency unsafe acts' forms and quantities of types of operations,including aerial spraying operations,commercial pilot license training operations,aerial forest protection operations,aerial prospecting operations and flight test operations have been identified.These unsafe acts should be preferentially controlled by general aviation companies,respective contains:6 kinds of forms,4 kinds of forms,4 kinds of forms,2 kinds of forms and 4 kinds of forms.?52 unsafe conditions are identified,including 20 kinds of forms.The results help General aviation companies clear about the need to focus on the control of 2 kinds of high-frequency unsafe conditions and their definitions,they are:engine failure(8 times)and wind related causes(8 times).The identified unsafe conditions are classified into categories and subcategories of 24Model-GA,it is concluded that 55.8%of unsafe conditions are physical environment,44.2%of unsafe conditions are technology environment.7 kinds of forms of physical environment and 13 kinds of forms of technical environment have been identified.It is clarified that the general aviation company plans before flight,such as understanding the weather characteristics of operating area,topographic directions,and making emergency plans,which can reduce unsafe conditions by 55.8%.?There are 282 indirect causes,among which 89.7%are flaws in safety consciousness,adverse mental states,and flaws in safety knowledge.The contents of 13 items of safety consciousness,16 items of mental states,and 13 items of safety knowledge are identified.It is clarified that enhance these contents can effectively prevent accidents.In addition,5 items of adverse physiological states and 4 items of laws in safety habits related to accidents are summarized.?202 deficiencies in safety management system are identified,among which 74.3%are deficiencies in safety management procedure.Further analysis of deficiencies in safety management procedure,among which 52.0%are deficiencies in system procedure.32.7%are deficiencies in operating procedures,and 15.3%are deficiencies in training program.The contents of 7 high-frequency items of system procedures,7 high-frequency items of operating procedures and 1 high-frequency item of training program are identified.The effective implementation safety policy of "safety first,prevention first and comprehensive management" by general aviation companies can reduce the deficiencies in safety management system by 11.9%.The deficiencies in safety management organizational structure of 86.7%stems from the deficiencies in responsibility distribution of the personnel of companies.The contents of 2 high-frequency items of deficiencies in responsibility distribution are identified.76.9%of resource management deficiencies resulted from the failure of the companies to provide equipment and facilities to ensure safety production,further clarifying the contents of 2 deficiencies of high-frequency equipment and facilities.?597 deficiencies in safety culture are identified.According to the definitions of 21 subcategories of safety culture in 24Model-GA,it has obtained 10 items of safety culture contents that need to be constructed by general aviation companies,such as role of safety management system,demand of safety training,safety importance,safety awareness.?48 deficiencies in external factors are identified.The identified deficiencies in external factors are classified into categories and subcategories of 24Model-GA,it is concluded that 64.6%of deficiencies in external factors are deficiencies in supervision by China Civil Aviation Administration(CAAC)and deficiencies in relevant companies of general aviation activities.The contents of 14 items and one high-frequency item of deficiencies in supervision by CAAC,14 items and one high-frequency item of deficiencies in relevant companies of general aviation activities are identified.8 types of aircraft models with defects in design and manufacture,such as Y12 are obtained.The contents of 7 items of deficiencies in laws and regulations that need to be improved are identified.(4)Using Bootstrap method,it is estimated that 27 subcategories in 24Model-GA which are steadily existed in larger accident samples(N>69)and their probability of occurrence are given,such as violation operation.By using four table Chi-square test,21 pairs of adjacent subcategories that are significantly correlated and 4 subcategories that have strong prediction effect on the occurrence of their adjacent subcategories are obtained.6 complete accident paths and 7 subcategories among the paths are identified.Based on the results of Chi-square test,9 key subcategories that need to be focused and preferentially solved by general aviation companies,such as adverse mental states are obtained.Two self-examination tables according to the 9 key subcategories are established for reference to daily accident prevention activities of the CAAC and general aviation companies.The research results can help the general aviation companies to take measures from the perspective of system,control and eliminate the key subcategories,help the general aviation companies to clarify the control focus of accident prevention and realize the rational allocation of resources.