Study on sampling size in flying test

How to judge the distribution of load spectrum and determine the sampling size in flying test are very important issues in the course of life prediction and compilation of load spectrum. Equivalent life was adopted to judge the distribution of load spectrum. According to t distribution theory, a method that can be applied to lognormal distribution was given and a new approach aiming at two-parameter Weibull distribution was put forward to attack the sampling size issue. These methods can offer useful references for life prediction and sampling size issue in flying test.