Reliability & Maintainability (R&M) Engineering

During System definition the R&M engineer, as part of the program SE team, should:

• Analyze conceptual design approaches and estimate the feasibility with respect to R&M performance capabilities
• Perform Analysis of Alternatives (AoA) trade-off studies among R&M, availability and other system performance parameters to arrive at a preferred system alternative. The studies should be performed in conjunction with product support, cost and design personnel, to ensure that user requirements are valid and feasible.
• Conduct a Reliability, Availability, Maintainability, and Cost (RAM-C) analysis. For Major Defense Acquisition Programs (MDAPs), prepare a preliminary RAM-C Rationale Report and attach the report to the Systems Engineering Plan (SEP) for Milestone A
• Translate user performance capabilities and requirement thresholds to R&M specification requirements based on the CONOPS/OMS/MP (Concept of Operations/Operational Mode Summary/Mission Profile) failure definitions, and utilization rates
• Develop an R&M engineering program plan. The plan should address the full life cycle of the program. Planning activities typically commence early in design and continue through operations and support.
  • A properly tailored R&M engineering program ensures that all elements are cost-effectively implemented and properly conducted, evaluated, reported, and integrated in a timely manner for design, analysis, development, testing, and manufacturing.
  • Planning the early stages should include the approach and procedures by which the contractor will ensure compliance with the proposed contractual requirements. The approach should also provide results of R&M design analyses and test results needed to support all major design reviews, program reviews, and milestones. These planning activities should be documented in the appropriate DoD acquisition component program plans and Integrated Master Schedule (IMS).
• Develop a system reliability growth planning curve and include it in the SEP. Reliability growth curves should be stated in a series of intermediate goals and tracked through fully integrated, system-level test and evaluation events until the reliability threshold is achieved. If a single curve is not adequate to describe overall system reliability, curves for critical subsystems, with rationale for their selection, should be provided
• Use data from the RAM-C Rationale Report to provide the following for logistics design support:
  • The planning factors and their values used to determine Mean Down Time (MDT) and other maintainability Key System Attributes (KSAs) or additional performance attributes are needed to validate Operational Availability (Ao) and Materiel Availability (Am) and should provide a realistic, definitive, and uniform basis to determine downtime. Failure rate and removal rate estimates, for both corrective and preventive maintenance, to provide a realistic basis for equipment and replaceable unit spares provisioning planning
• Define contractor R&M engineering activities in the Request for Proposals (RFP) and contract Statement of Work (SOW) for the Technology Maturation and Risk Reduction (TMRR) phase, which should include:
  • Allocations
  • Block diagrams and modeling
  • Predictions
  • Failure Modes, Effects, and Criticality Analysis (FMECA)
  • Subsystem and system-level reliability growth planning activities
  • R&M tests and demonstrations
  • Failure Reporting, Analysis and Corrective Action System (FRACAS)

During preliminary design, the R&M engineer, as part of the program SE team, should:

• Participate in trade studies during requirements analysis and architecture design
• Review results of R&M engineering analyses, verification tests, design approach, availability assessments, and maintenance concept optimization to verify conformance to requirements, and to identify potential R&M problem areas
• Contribute to integrated test planning to avoid duplication and afford a more complete utilization of all test data for R&M assessment. Comprehensive test planning should include subsystem reliability growth and maintainability and Built-in Test (BIT) demonstrations as appropriate
• Understand schedule and resource constraints, and adjust the reliability growth planning curve based on more mature knowledge points
• Integrate R&M engineering analyses with logistics design support in the following areas: requirements and functional analysis; test planning; Reliability-Centered Maintenance (RCM) and Condition-Based Maintenance Plus (CBM+); and refinement of the maintenance concept, including the Level of Repair Analysis (LORA) and maintenance task analysis
• Verify that plans have been established for the selection and application criteria of parts, materials and processes to limit reliability risks
• Define contractor R&M engineering activities in the RFP and contract SOW during which R&M quantitative requirements and verification methods are incorporated
• Update the RAM-C analysis to ensure R&M user requirement thresholds are valid and feasible. For MDAPs, attach the updated RAM-C Rationale Report to the SEP for Milestone B

During detailed design, the R&M engineer, as part of the program SE team, should:

• Perform evaluations to assess R&M status and problems
• Update the RAM-C analysis, ensuring the R&M user requirement thresholds are valid and feasible. For MDAPs, attach the updated RAM-C Rationale Report to the SEP for Milestone C
• Ensure that the product baseline design and required testing can meet the R&M requirements
• Ensure the final FMECA identifies failure modes, and their detection methods, that could result in personnel injury and/or mission loss, and ensure they are mitigated in the design
• Ensure that the detailed R&M prediction to assess system potential to meet design requirements is complete
• Verify through appropriate subsystem/equipment-level tests the readiness to enter system-level testing at or above the initial reliability established in the reliability growth planning curve in both the SEP and the Test and Evaluation Master Plan (TEMP)
• Verify system conformance to specified R&M requirements through appropriate demonstration and test
• Implement a FRACAS to ensure feedback of failure data during test and to apply and track corrective actions
• Coordinate with the Chief Developmental Tester (T&E Lead) and Operational Test Agencies (OTAs) to ensure that the program office and OTA data collection agree on R&M monitoring and failure definitions, and that R&M and BIT scoring processes are consistent in verification of requirements through all levels of testing
• Define contractor R&M engineering activities in the RFP and contract SOW to ensure adequate R&M engineering activities take place during production and the RFP and contract SOW provide adequate consideration of R&M in re-procurements, spares and repair parts. An essential activity during production is the FRACAS process.
• Verify that parts, materials, and processes meet system requirements through the use of a management plan detailing reliability risk considerations and evaluation strategies for the intended service life. Include flow of requirements to subcontractors and suppliers. See MILSTD-1546 (Parts, Materials, and Processes Control Program for Space and Launch Vehicles) and MIL-STD-1547 (Electronic Parts, Materials, and Processes for Space and Launch Vehicles) and MIL-STD-11991 (General Standard for Parts, Materials, and Processes)

During production or fabrication, assembly, integration, and test (FAIT), the R&M engineer, as part of the programs SE team should:

• Verify initial production control of R&M degradation factors by test and inspection, production data analysis, and supplemental tests
• Verify R&M characteristics, maintenance concept, repair policies, Government technical evaluation, and maintenance procedures by T&E
• Identify R&M and production-related BIT improvement opportunities via FRACAS and field data assessment
• Review Engineering Change Proposals (ECPs), operational mission/deployment changes, and variations for impact on R&M
• Update R&M predictions and FMECAs based on production tests, demonstration tests, operational evaluation, and field results and apply them to the models previously developed to assess impacts on maintenance procedures, spares, manpower, packaging design, test equipment, missions, and availability
• Verify that parts, materials, and processes management requirements for limiting reliability risk and lessons learned are used during all design change efforts including change proposals, variations, substitutions, product improvement efforts, or any other hardware change effort

During operations and support, the R&M engineer, as part of the program SE team should:

• Assess operational data to determine the adequacy of R&M and BIT characteristics performance; maintenance planning, features and procedures; provisioning plans, test equipment design; and maintenance training
• Identify problem areas for correction through ongoing closed-loop FRACAS and field data assessment
• Monitor availability rates and respond to negative trends and data anomalies