New concept for aircraft maintenance management. II. The establishment of the spoon-shaped curve model

On the basis of many years' analyses and studies on abundant statistical data, and taking specialists' experiences into consideration, the authors of this paper have discovered the statistical law of resource consumption of field maintenance-man-hours-the spoon-shaped curve model. The famous model-the bath-tub curve model has revealed the general law of failure concerning product life from the angle of reliability, while the spoon-shaped model enables us to understand the relation between maintenance and product life from the angle of maintainability. The consequence of failure is opposite to the result of maintenance. The life profile of an aircraft is a unity of opposites. It can be thought of as a conflicting process between failure process and maintenance process, and the end of this contradiction always means the end of life for the aircraft. The bath-tub model describes the process of failure, while the spoon-shaped model reveals the process of maintenance. Both of them are descriptions of the process of product's operation life. In this paper, the authors have adopted the method of statistical analysis to find out maintenance ratio curve, expecting to recognize macroscopically the basic law of maintenance process, and then to proceed to the next step with the aim of controlling the consumption of maintenance-man-hours resources so that it will play a positive role in raising the level of maintenance and management of modern aircraft. Thus it makes new recognition of the aircraft maintenance and management.