DEPARTMENT OF DEFENSE HANDBOOK - …

1 NOT MEASUREMENTSENSITIVEMIL-HDBK-470A4 AUGUST 1997 SUPERSEDINGMIL-HDBK-47012 JUNE 1995 MIL-HDBK-47112 JUNE 1995 DEPARTMENT OF DEFENSEHANDBOOKDESIGNING AND DEVELOPING MAINTAINABLEPRODUCTS AND SYSTEMSVOLUME IThis HANDBOOK is for guidance only. Do not cite this document as arequirementAMSC N/AAREA MNTYDISTRIBUTION STATEMENT A. Approved for public release; distribution is This HANDBOOK is approved for use by all Departments and Agencies of the DEPARTMENT ofDefense (DoD). It was developed by the DoD with the assistance of the military departments,federal agencies, and industry and replaces in their entirety Military Handbooks 470 and 471(both formerly military standards). The HANDBOOK provides guidance to maintainability managersand engineers in developing and implementing a sound maintainability program for all types This HANDBOOK is for guidance only.

2 This HANDBOOK cannot be cited as a requirement. If it is,the contractor does not have to Maintainability is a discipline that has become more importance over the past 30 years asmilitary systems became more complex, support costs increased, and DEFENSE budgets is also important in the commercial sector, where high levels of maintainability are increasinglybecoming an important factor in gaining customer loyalty. In fact, American products that oncewere shunned in favor of foreign alternatives recently have made or are making a comeback. Thisshift in consumer preferences has been directly attributed to significant improvements in thequality of the American products, a quality that includes good Despite the fact that maintainability has been a recognized discipline for much longer than 30years, achieving the high levels of maintainability needed in military and complex industrialsystems is too often an elusive goal.

3 System complexity, competing performance requirements,the rush to incorporate promising but immature technologies, and the pressures of acquisitionbudget and schedule contribute to this Noting the significant improvement in the quality of commercial products and the rapiditywith which new technology is incorporated in commercial products, and facing a shrinkingdefense budget, the DEPARTMENT of DEFENSE changed its acquisition policies to foster theevolution of a unified military and commercial industrial base. The objective is to capitalize onthe "best practices" that American business has developed or adopted, primarily in response toforeign competitive pressures. When combined with the knowledge and expertise of militarycontractors in building complex, effective military systems (soundly demonstrated during DesertStorm), these commercial practices will help the DEPARTMENT of DEFENSE to acquire world-classsystems on time and within The information in this HANDBOOK reflects both the move to incorporate commercial practicesand the lessons learned over many years of acquiring weapon systems "by the book.

4 " Whenappropriate, commercial standards are cited herein for reference. Military standards andspecifications, which cannot be used as requirements in solicitations without obtaining a waiver,are also cited for guidance. These documents are familiar to both military and commercialcompanies, contain a wealth of valuable information, and often have no commercial many of these documents emphasize what to do and how to do it, this HANDBOOK , in theMIL-HDBK-470 Aiiispirit of the new policies regarding acquisition, focuses on the objectives of a soundmaintainability program and the tools available to meet these Beneficial comments (recommendations, additions, deletions) and any pertinent data whichmay be useful in improving this document should be addressed to: Rome Laboratory/ERSR, 525 Brooks Road, Rome, NY 13441-4505.

5 Comments should be submitted using the self-addressedStandardization Document Improvement Proposal (DD Form 1426) appearing at the end of thisdocument or by .. SCOPE AND PURPOSE OF Scope .. Purpose of the HANDBOOK .. Using the Applicable Definitions, Acronyms and Abbreviations .. THE CONCEPT OF MAINTAINABILITY .. What is Maintainability?.. Effect of Maintainability on Operations and Cost .. Relationship of Reliability and and Operational Readiness.. Life Cycle Research and Development (R&D) Costs (DoDPhases 0, I, and II).. Production and Construction (P&C) Costs (Part ofDoD Phase III).. Operation and Maintenance (O&M) Costs (Part ofDoD Phase III).. Product Retirement and Phase-out (PR&P) Costs.. Opportunity and Equivalent Affordability.

6 Other Relationships.. Manufacturing .. Safety .. and Logistics Support .. Maintainability and the Acquisition Process.. OBJECTIVE OF A MAINTAINABILITY PROGRAM .. Understand the Customer's Maintainability Needs.. Maintainability with the Systems Engineering Process.. Thoroughly Understand the Design .. for Desired Level of Validate the Maintainability Through Analysis and Development Test.. Monitor and Analyze Operational ELEMENTS OF A MAINTAINABILITY PROGRAM .. Overview.. Management Clear Adequate Resources (Quantity and Quality).. of Communication .. Integration with Related Functions.. and Vendor Reviews.. Design for Maintainability.. Considerations.. Support Operational and Support Environment.. Versus Corrective Maintenance Requirements.

7 Engineering (HE).. Presentation of Information .. Anthropometrics .. Maintenance Tools and Support Equipment.. Testability and Testability Design .. Diagnostic and Connections .. and Induced Failures.. Standardization and Interchangeability .. Standardization Design Goals and Interchangeability Design Goals and Principles .. Design Tools.. Analytical.. and Virtual Reality .. and Other Reference Documents.. Expert Systems .. Rule-Based Expert Systems .. Model-Based Expert Fuzzy Logic .. Neural Networks .. Maintainability Analyses and Objectives of Maintainability .. Typical Products of Maintainability Analyses .. Commonly Used Maintainability Analyses .. Equipment Downtime Design Failure Modes and Effects Analysis (FMEA).

8 Testability Dependency Analysis .. Dependency Analysis Other Types of Human Factors Quantitative Measures of Maintainability Models and MaintenanceActivities Block Qualitative Maintainability Factors.. Predictions, Allocations, and Maintainability Prediction .. Maintainability Prediction inAccordance with Maintainability Allocation .. Failure Rate Complexity Method .. of the Failure RateComplexity Equal Distribution Method .. Maintainability Assessment .. Types of Statistical Distributions Used in Maintainability Models .. Distribution .. Normal Distribution .. Exponential Distribution .. Data Collection and Types of Data .. Development Field Data .. Sources of Data .. Data Analysis Techniques.

9 Used Explicitly for Compliance Verification .. Uses of Data ..4-64 APPENDIXESA ppendix A. Acquisition Guidance, Templates for Preparing Maintainability Section ofSolicitation, and Guidance for Selecting Sources..A-1 Appendix B. Maintainability Test and Demonstration Methods..B-1 Appendix C. Design Guidelines (Volume II of HANDBOOK ) ..C-1 Appendix D. Maintainability Predictions..D-1 Appendix E. Phasing of Maintainability Elements..E-1 Appendix F. Maintainability G. Maintainability Glossary of Terms, Definitions, Acronyms andAbbreviations..G-1 FIGURESF igure 1:Different Combinations of MTBF and MTTR Yield the SameInherent 2:Some Key Disciplines to Which Maintainability is Related ..2-8 Figure 3:QFD House of Quality ..3-3 Figure 4:Example Excerpt of House of Quality ..3-4 Figure 5:Major Categories of Maintenance.

10 4-7 Figure 6:The Steps in an RCM Approach to Identifying Preventive Maintenance ..4-8 Figure 7:The Human Information Processing System ..4-10 Figure 8:Interactions Between Human and Product ..4-11 Figure 9:Steps in a General Approach for the Physical Development of aMaintainability Expert System ..4-28 Figure 10:Fuzzy Logic Set 11:Typical Neural Network 12:Steps in an FMEA ..4-36 Figure 13:Typical FMEA Worksheet ..4-36 Figure 14:Abbreviated Results from FMEA of a Solid Propellant Rocket Motor ..4-37 MIL-HDBK-470 AviiiFIGURES (Continued)Figure 15:Simple System Showing Test Dependencies ..4-38 Figure 16:Maintenance Activities Block 17:Example of Maintainability Allocation ..4-50 Figure 18:Example FRACAS A-1:Sections of a Government Solicitation or A-2 Example Wording for a Statement of A-3:Checklist for Evaluating Maintainability Portion of a Proposal.