Research on evaluation approaches of maintainability growth based on classification data

Aimed at the characteristics which the maintainability of aircrafts is unstable in the flight-test phase, this paper discusses the approaches of evaluating maintainability growth in case of small samples of field data. It puts emphasis on the analysis of the field data´s classification. Firstly, the data are classified from two situations of maintenance process and maintenance implements. Then, the sort of data is judged according to their logic relationship. Finally, the maximum likelihood model for evaluating the maintainability growth is established. Based on a case study, the paper proves the approach and model´s validity on the comparison of traditional evaluation results.