Abstract: A maintainability allocation method based on system complexity is presented. For agivensystem consisting of series subsystems composed of the sameitems, the application conditions of usingthe presented method to allocate MTTR ( mean time to repair ) to eachitem are discussed. The lifedistribution law of a subsystem in the case that the probability of concurr ent failure of the sameitemsin the subsystem be a minimum is discussed and proved. The impact of the life distribution law on theallocation method is also discussed. Finally, the necessary constraints and error compar ison are givenby an example.

Key words: maint ainability, failure, rations