Statistics of aircraft accidents and case studies on structure or material related accidents

The database of world aircraft accidents, which covers most of the fatal or hull-loss accidents of aircraft heavier than 5,600 kgw since 1954, has been developed to study the critical causing factors. As examples of data analyses, major accident causes, the factors which induced pilot errors (the main cause of accidents), and the chronological trends of accident patterns have been discussed. The causing factors are categorized into four groups. They are three Ms and one E, namely Man, Machine, Management and Environment. Moreover, interest was focused on the accidents induced by the inadequate design or manufacturing, or defects of materials. The factors causing structural failure were closely examined by case studies of typical accidents. It was pointed out that the carelessness of the maintenance staffs, defects during manufacturing and improper management are the major elements of the accidents related to the structural failures.