Abstract : This report presents the results and data resulting from a research evaluation made of the reliability growth characteristics of the development and early production of UH-1D and AH-1G helicopters. The major subjects covered by the technique and backed by research are: off-board MTBF, reliability (MTBF) growth versus test time, and reliability growth versus calendar time. A tentative technique for predicting helicopter reliability growth applicable to reliability program planning and management is also presented based on the results of the research. An example of the technique procedures applied to a hypothetical helicopter is also presented.