DOD 3235.1-H (3RD Ed), TEST AND EVALUATION OF SYSTEM RELIABILITY, AVAILABILITY, AND MAINTAINABILITY (A PRIMER) (MAR 1982)
DOD 3235.1-H (3RD Ed), TEST AND EVALUATION OF SYSTEM RELIABILITY, AVAILABILITY, AND MAINTAINABILITY (A PRIMER) (MAR 1982)., This handbook is issued under the authority of DoD Instruction 3235.1, “Test
and Evaluation of System Reliability, Availability, and Maintainability,”
February 1, 1982. Its purpose is to provide instruction in the analytical
assessment of System Reliability, Availability, and Maintainability (RAM)
performance. One step in the acquisition of military weapon systems and equipment is the
verification that the candidate systems do, in fact, perform in accordance
with previously specified operational requirements. The verification process
involves the design of test programs which provide an adequate data base to
support realistic assessments of hardware characteristics. This text outlines
the concepts and techniques to be used in structuring such test programs and
analyzing the resulting data.
Since verifying the performance of every hardware item to be procured is
neither practical nor possible, we base our projection of the entire populationâ€™s
performance on the assessment of an available sample. This sample may
consist of the first 10 preproduction aircraft of a projected buy of 725 or 50
percent of a lot of high-reliability pyrotechnic devices. In either case, we
are utilizing statistical techniques to project or estimate the true value of
some populationâ€™s characteristic, such as reliability, maintainability,
weight, size, etc.
The material contained in the following chapters is designed to familiarize
the reader with the various statistical concepts and techniques required to
thoroughly understand the relationships among test design, assessment and
projection of population characteristics.
The beginning chapters present background material on the three basic quantitative
system parameters: reliability, availability and maintainability. The
various definitions of these basic terms are discussed, as are the relationships
among these parameters. The statistical concepts of confidence and
producerâ€™s and consumerâ€™s risk are next introduced, with the majority of the
text devoted to the practical application and significance of these concepts.
The chapters utilize a combination of narrative and case studies to introduce
and illustrate the usefulness of the concepts. It will prove quite useful to
refer to the case studies while reading through the chapters. This study
technique will prove especially helpful in Chapters 7 and 8, which present
information on analyzing test data and structuring statistically adequate test
programs. Chapter 9 contains an introductory discussion of the reliability
growth concept. Chapter 10 presents qualitative aspects of test planning
along with a description of data collection requirements.