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Reliability and Maintainability Engineering

The purpose of Reliability and Maintainability (R&M) engineering is to influence system design in order to increase mission capability and availability and decrease logistics burden and cost over a system’s life cycle. R&M engineering supports designing a system that will operate reliably and can be maintained in the sustainment phase of acquisition. Properly planned, R&M engineering reduces cost and schedule risks by preventing or identifying R&M deficiencies early in development. This early action results in increased acquisition efficiency and higher success rates during operational testing and the development process.

R&M parameters (e.g., mission and logistics reliability, corrective maintenance, built-in test) are important characteristics used in measuring the operational suitability and effectiveness of Department of Defense (DoD) weapon systems. R&M parameters also relate to other system parameters, primarily those that characterize the system performance, readiness, logistics supportability, and total ownership cost. The R&M parameters and particular levels of performance support other system parameters essential to the success of the mission.

Results of R&M engineering activities are essential for programmatic decision and control functions. The R&M design methods and procedures are not new, but the challenge occurs in the diligent management of these methods and procedures to achieve reliable and maintainable systems. Effective management control of the R&M program, using the policies and guidance set forth by DoD, are intended to ensure timely performance of the necessary R&M activities to achieve the requirements and the development of adequate data to assess R&M at major milestones.


The R&M policy for DoD materiel is established in DoD Instruction (DoDI) 5000.02, Operation of the Defense Acquisition System. The responsibility for achieving R&M throughout the life cycle is assigned to the heads of the DoD Components. Program Managers for Major Defense Acquisition Programs are required to implement a life cycle R&M engineering program.

DoDI 5000.02 Enclosure 3, Systems Engineering provides the following policy relating to R&M Engineering:

  • Formulate comprehensive R&M program, consisting of engineering activities including:
    • R&M allocations, block diagrams, and predictions
    • Failure definition and scoring criteria
    • Failure Mode, Effects, and Criticality Analysis (FMECA)
    • Built-in Test (BIT) and maintainability demonstrations
    • Reliability Growth testing at system/subsystem level
    • Failure Reporting, Analysis, and Corrective Action System (FRACAS)
  • Prepare a preliminary Reliability, Availability, Maintainability and Cost (RAM-C) Rationale Report in support of Milestone (MS) A and updated for RFP Release Decision Point, MS B, and MS C.
  • Develop reliability growth strategy to include:
    • System-level reliability growth curves in the Systems Engineering Plan (SEP) beginning at MS A and updated in the Test and Evaluation Master Plan (TEMP) beginning at MS B
    • Intermediate goals for reliability growth curves tracked through fully integrated system-level T&E events until the threshold is achieved
    • PMs and Operational Test Agencies to assess reliability growth required to achieve the reliability threshold during Initial Operational Test and Evaluation (IOT&E)
  • Tracking and monitoring of reliability growth throughout the acquisition process


Defense Acquisition Guidebook Chapter 3, 4.3.19 Reliability and Maintainability Engineering

Guidance for Tailoring R&M Engineering Data

RAM-C Rationale Report Outline Guidance: Word | PDF | Training Brief

The RAM-C relationship for particular levels of performance provides a measure of system effectiveness within which considerable trade-off potential usually exists. This potential should be reevaluated at each stage of system development to optimize the balance among reliability, maintainability, availability, and other system performance parameters with respect to technical risks, life cycle cost, acquisition schedule, and operating and maintenance requirements. The RAM-C Rationale Report Outline Guidance describes this relationship and the associated trade-off process.

Papers and Presentations

Essential Elements of an R&M Engineering Program
19th Annual NDIA Systems Engineering Conference, Springfield, VA, October 26, 2016

2016 Reliability and Maintainability Symposium Keynote
Reliability and Maintainability Symposium, Tucson, AZ, January 25, 2016

R&M: Critical to Success in a Technology Reliant World
Reliability and Maintainability Symposium, Tucson, AZ, January 27, 2016

What Is in an Effective RAM-C Rationale Report?
18th Annual NDIA Systems Engineering Conference, Springfield, VA, October 28, 2015

DASD(SE) Reliability and Maintainability Initiatives
17th Annual NDIA Systems Engineering Conference, Springfield, VA, October 30, 2014

For more information, please contact the DASD(SE) R&M Engineering team.