Having an airworthiness certificate for aircraft is important to the extent that it completely affects its entry into the production and market arena, and its receipt or non-receipt of this certificate can determine the fate of the project and the investments.Obtaining airworthiness certificates for aircraft and also continuing airworthiness requires performing initial, supplemental and in-service tests, which entail high costs for the designer, manufacturer and operator. This article uses reliability concepts and techniques to predict the effectiveness of certification tests in the progress of obtaining an airworthiness certification and also presented a model for developing a certification program.The scope of studies has been considered in the section of longitudinal static stability requirements. As a case study, Piper series fleet has been examined and the process of calculating the growth rate of reliability by performing certification tests has been stated. By considering the improvement rate of the system reliability at each step, the certification program has been extracted in the subsection of longitudinal static stability requirements. Therefore, by using this method, it is possible to achieve a model in which the aircraft certification program developed based on the importance of the certification tests in the safety of that aircraft and, consequently, the impact on the process of proving airworthiness. In a case study, propsed model is able to reduce the number of certification tests from 36 to 9 critical point tests, while increasing the safety of the aircraft, can reduce the costs and time of certification tests for proofing the product.