Based on results of distribution characteristic of durability load accumulation of fixed task frequency mixing

distribution characteristic of durability load accumulation based on changeable task frequency mixing was deduced. Results show that distribution function of durability load accumalation of changeable task frequency mixing tends to be normal as well. The process of durability load accumulation with changeable task frequency mixing in real flying operation was demonstrated by numerical simulation

and the numerical results coincide with the theoretical results

which further demonstrates the analyzed results. Results can be used in life reliability forecasting based on changeable task frequency mixing.