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Log 211 Supportability Analysis Student Guide

Lesson 8: Reliability Centered Maintenance Analysis

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Slide 8-1. Lesson 8: Reliability Centered Maintenance Analysis

Welcome to Lesson 8: Reliability Centered Maintenance Analysis.

January 2013Final v1.3

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LOG 211 Supportability Analysis Student Guide

Topic 1: Introduction

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Slide 8-2. Topic 1: Introduction

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Slide 8-3. Life Cycle Mangement Framework:

Where Are You? What Influence Do You Have?

Reliability Centered Maintenance (RCM) Analysis determines the most applicable and effective maintenance tasks for a physical asset, such as an airplane or a manufacturing production line. RCM Analysis balances an acceptable level of operability with an acceptable level of risk, considering cost and Availability.

The outputs of RCM Analysis are the inputs into:

Maintenance Task Analysis (MTA) and Technical Manual Tasks, which determine:

o What is the complete definition of the maintenance task (i.e., task steps, tools, equipment, and testing)?

o How often is maintenance performed?o What resources are required?o What source data is required for the development of technical

manuals?

Level of Repair Analysis (LORA), which determines:

o At what echelon of maintenance are the tasks performed?o What are the Operation & Support (O&S) Costs of the tasks?


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Technology Maturation & Risk

Reduction

PDallosta, 02/24/14,

Slide 8-3 page 8-3 update to TMRR


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Where Are You?

RCM Analysis spans the Life Cycle Management Framework, from the initial design through Operations & Support to disposal.

For competitive prototypes, initial identification of maintenance task candidates and task intervals for critical failures begins in the Technology Development –Maturation and Risk Reduction (TMRR) phase.

RCM is conducted again during Engineering & Manufacturing Development, as the system’s design matures and is finalized.

During the Operations & Support phase, system performance and maintenance data are collected, and serve as inputs to additional RCM Analysis, as necessary. This continuous Supportability Analysis process facilitates improvements in design and promotes maintenance efficiency, suitability, and operational effectiveness.

What Influence Do You Have?

RCM Analysis is the bridge between Reliability Engineering and Product Support. While Reliability Engineers conduct RCM Analysis, the Life Cycle Logisticians (LCLs) play a prominent role in reviewing the analysis outcomes in terms of effectiveness and suitability. These outcomes are and therefore should be in lock step with the Maintenance Task Analysis, which RCM Analysis impacts directly. The LCL role is further detailed in Lesson 9: Maintenance Task Analysis (MTA).



Updated TMRR


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Slide 8-4. RCM Analysis Lesson Approach

Key questions in this lesson are:

What actions reduce the probability, identify the onset, and limit the consequences of failure?

What mitigating actions will enable the system to meet Availability KPP/KSA requirements?


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Slide 8-5. Topics and Objectives



Topic 2: Overview of RCM Analysis

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Slide 8-6. Topic 2: Overview of RCM Analysis


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Slide 8-7. What Is RCM Analysis?

RCM Analysis is a logical decision process that identifies technically appropriate, cost-effective, and defensible maintenance approaches for failure modes identified in Failure Mode Effects and Criticality Analysis (FMECA) and Fault Tree Analysis (FTA).

RCM Analysis does not prevent all failures, but mitigates failure consequences in order to meet system Availability requirements. To do this, RCM recommends one or several maintenance options, creating an optimal balance. The following factors are included in maintenance option decisions:

Proactive maintenance tasks (known as “preventive” to logisticians)

Tasks that identify and address the need for maintenance before the failure occurs.

Condition-based (predictive maintenance)—Identifies the onset of failure and predicts the remaining useful life of an item. On-condition tasks are performed based upon “evidence of need,” rather than as a scheduled or planned maintenance action.

Interval-based (preventive maintenance)—Schedules maintenance on a regular basis, before failure, regardless of condition.

Reactive Maintenance Tasks (known as “corrective” to logisticians)

Allows “run-to-failure”, followed by repair to restore item. Determines root cause of failure at lowest cost and in least time. Mitigates consequences after failure (secondary effects).



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Cost (Affordability of Repair)

Manpower Equipment Facilities

Other actions

Redesign for Maintainability (accessibility, modularity, testability) Training programs Technical manuals Operating and Maintenance procedures Safety and Emergency procedures

Additionally, RCM Analysis establishes the necessary maintenance task intervals, as well as cost implications for recommended maintenance tasks.


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Slide 8-8. What is RCM Analysis?: Significant Functions

An item’s functional mission significance determines the applicability of RCM Analysis; not every functional failure qualifies for RCM Analysis. All possible effects of a failure mode, including secondary effects, are considered when assessing significance.

FMECA/FTA identify criticality of functional failures, providing the data from which to determine functional significance:

Functions Functional failures Failure modes Failure mechanisms Failure effects (primary and secondary) Criticality

A function is significant if one or more of the following criteria apply:

Does the loss have an adverse effect on operating safety? Does the loss have an adverse effect on the environment (leading to

serious violation of environmental standards/requirements)? Does the loss have an adverse effect on operations? Does the loss have an adverse effect on economics? Is this function protected by an existing preventive maintenance (PM)

task?



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If none of the criteria apply, the function is not a candidate for further RCM Analysis, and therefore not a candidate for preventive maintenance. For non-significant functions, the assigned maintenance strategy is run-to-failure, followed by corrective action.


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Slide 8-9. What is RCM Anaysis?: Inputs & Influence

RCM Analysis functions across a larger framework of FMECA/FTA, MTA, and LORA, and serves as a refinement to the maintenance planning process.

As shown in this slide, FMECA identifies failure modes and their criticality. Non-significant failures are assigned corrective maintenance tasks, which then act as inputs directly into the MTA. Significant failures undergo RCM Analysis.

While FMECA identifies failure modes and their criticalities, RCM Analysis goes further. RCM Analysis develops mitigation strategies to reduce failure modes from cascading into catastrophic events by inserting preventive tasks or influencing remove and replace intervals. RCM Analysis outputs include both new and refined corrective and preventive maintenance tasks/frequencies. As with FMECA, both sets of RCM Analysis outputs are direct inputs to the MTA. These new tasks are added to MTA activities, while the existing tasks are modified to reflect RCM instructions.



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All corrective and preventive maintenance tasks documented by the MTA are reviewed and promoted to the Logistics Product Database. The Logistics Product Database can then provide this information to other requirements, such as the Level of Repair Analysis (LORA) and the technical manuals.

For RCM Analysis to be effective, it must be integrated with the MTA in this broader framework.


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Slide 8-10. What is RCM Analysis?: ASOE Model

As previously mentioned, in the Affordable System Operational Effectiveness (ASOE) Model, Technical Performance and Supportability bolster Design Effectiveness, which, in conjunction with Process Efficiency, generates Mission Effectiveness. It is through Mission Effectiveness, when coupled with Ownership Costs, that the most operationally effective, suitable, and affordable system is realized.

Through selecting the most appropriate and cost-effective maintenance tasks, RCM Analysis contributes to ASOE by optimizing design and mission effectiveness, while reducing Life Cycle Cost/Total Ownership Cost, in the following ways:

RCM Analysis Impact on Design Effectiveness

Determines the most appropriate and effective maintenance tasks to meet and sustain requirements for:o Reliabilityo Availabilityo Maintainabilityo Operational readiness

Achieves longer useful life for weapons system components Enhances Human Systems Integration (safety) Improves environmental integrity—reduces potential of failure mode

that breaches OSHA, departmental or international (if NATO mission) environmental regulations



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RCM Analysis Impact on Mission Effectiveness

Increases maintenance efficiencyo Greater productivityo Shorter maintenance cycleso Increased quality of processo Better use of resourceso Decreased logistics footprint

Provides for continuous improvement of maintenance program/ equipment performance

Provides documentation trail for maintenance program changes

RCM Analysis Impact on Life Cycle Costs/Total Ownership Costs (Design Affordability)

Reduces overall Life Cycle Costs by reducing costs in the Operations & Support phase


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Slide 8-11. ASOE Trade-Off: Reliability vs. Maintenance

This slide shows the trade-off linkage during RCM Analysis that enables Affordability and Supportability. Specifically, imperfect Reliability results in failure mode consequences. Significant failures are mitigated through maintenance task strategies designed to achieve the most efficient and effective support strategy, which in turn, reduces O&S Cost.



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Slide 8-12. What is RCM Analysis: Inputs and Outputs

This diagram provides a high-level view of RCM Analysis process inputs and outputs.


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Topic 3: Set Up – Building a Plan and Gathering Inputs

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Slide 8-13. Topic 3: Set Up – Building a Plan and Gathering Inputs



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Slide 8-14. Set Up

Preparing for RCM Analysis includes planning for analysis activities that occur throughout the life cycle of a system, selecting a suitable RCM Analysis tool to support and manage the process, and defining and importing the data inputs required for task selection.


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Slide 8-15. Build a Plan: Process and Data Management

The Set Up phase is planning oriented, considering analysis activities ranging from initial task selection to refinement based on operation and maintenance data gathered during Sustainment.

Role of the Integrated Product Team (IPT)

IPT members who are responsible for RCM Analysis require a solid understanding of design, Reliability principles, and maintenance.

During the initial Set Up, the IPT:

Identifies roles: Who is doing what? Example roles include the following:o Program Manager—Program Manager responsibilities with regards

to RCM Analysis are to plan, develop, program, and implement RCM processes and outputs.

o Test personnel—Maintenance task choices feed the test environment (e.g., draft manual, test article selection, operator training, testing of task). Therefore, test personnel should be involved in maintenance task selection along with the engineer and logistician.

Establishes Working-level Integrated Product Team (WIPT) expectations, providing examples of the RCM Analysis process and the WIPT’s role


SAE GEIA-STD-0007


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Content Defines the analysis goal Defines the schedule/timeline Plans for Sustainment

Planning for Sustainment

An RCM Sustainment program measures essential performance requirements to demonstrate effectiveness. Operational data is collected, including maintenance, failure, and repair data. This information enables the IPT to monitor, analyze, update, and refine product design and maintenance programs, as warranted.

Examples of issues addressed by an RCM Sustainment program are:

Incorrect assumptions made on initial analysis for new programs that lacked reliable data

Equipment/hardware changes Unexpected failures Operating environment changes

Common Monitoring Activities

Monitoring requires organized Information Systems (IS) to conduct monitoring under actual operating conditions. Operational data include:

Performance metricso Business: ROI/cost-benefit for initial RCM Analysis and Sustainmento Program management: training, schedules, number of systems

analyzed, etc.o Technical: equipment behavior (MTBF, readiness and Availability,

servicing actions, maintenance man-hours) Trend analysis Product Support Package and documentation reviews Age exploration (collection of operational and test data, see DoDM

4151.22-M, June 30, 2011 Encl 2 para 2.g.(4)) Existing and emergent (future) failure modes Top degraders (e.g., highest failure rates or impact on Availability and

Maintainability) and cost drivers Fleet leader programs (a type of test program where the weapon

system is subjected to slightly accelerated operating conditions so that designated systems ‘lead’ the actual population both in time and load. The program’s intent is to provide advanced warning of serious design flaws to avert a major incident and potential loss of life)

Opportunities for process improvements and technology insertion Changes to equipment operating profile and environment


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Results of Sustainment Analyses

Collection of operational data provides a feedback loop to refine analyses, brings greater confidence to recommended corrections, and validates maintenance plan cost target performance. The result: safe operations and cost-effective readiness.

Specific Sustainment analyses recommendations include:

Adjusting maintenance intervals Adding, deleting, or modifying preventive maintenance tasks,

procedures, or requirements Modifying age exploration tasks Providing recommendations for redesign Changing maintenance processes Restricting operations



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Slide 8-16. Determine Data Inputs

RCM Analysis Data Inputs

1. Design characteristicso Capability Development Document (CDD)o Built In Test (BIT)o Sensors

2. System configurationo Engineering data, studies, and drawingso Design reportso Product specification sheetso Production inspection recordso Vendor informationo Original Equipment Manufacturer (OEM)

3. Developmental testing resultso Test result reportso Engineering investigation reportso Modeling and simulation data

4. Subject matter experts with knowledge of equipment and operating contexto Operatoro Maintainero In-service engineero Technical representativeo Program Manager


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SAE GEIA-STD-0007


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5. Reliability analyseso Reliability characteristicso Time to Failure (calculated or estimated) for non-reparable itemso Mean Time Between Failure (MTBF) for reparable items

Average time a system operates without failure (assuming no PM in place) under a prescribed set of conditions

Average age if allowed to run-to-failure (RTF) (without PM, under normal operating conditions)

In-service data usually not used in RCM Analysis MTBF, because some PM already in place

Prioritized failure modes that require further analysis Determines need and frequency for PM maintenance Time in RCM Analysis is units related to failure mode (cycles,

miles, hours, landings)o Reliability Block Diagramso Failure characteristics

Potential failure conditions Failure distribution curve (calculated or estimate) Wear out/life limit age Random failures

o Failure mode occurring within service life of equipmento Test data

6. Maintainability analyseso Mean Time Between Maintenance (MTBM)o Mean Time to Repair (MTTR)o Mean Down Time (MDT)o Mean Repair Time (MRT)o Maintenance Task Analysis

7. Maintainability: Engineering Considerationso Accessibilityo Modularityo Testability

Built In Test architecture Ambiguity groups/BIT effectiveness/detection rates/false

reports8. Failure Mode Effects and Criticality Analysis (FMECA) results

o Functions, functional failures, failure modes, failure effectso Severity class for failure mode (criticality)

9. Fault Tree Analysis (FTA) results10. Human Systems Integration (safety and hazard analysis)11. Maintenance data systems

o Previous maintenance planso In-service performance datao Item repair histories



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12. Failure Reporting, Analysis, and Corrective Action System (FRACAS)o FRACAS is system of reporting and analyzing failures,

recommending corrective actiono Developed from Test & Evaluation (T&E) events and field

failure/repairso Common data captured in FRACAS include field MTTR, MTBF,

Reliability growth, failure analysis (incident, type, location, root cause, etc.)

13. Cost data

RCM Analytical Tools

Currently, there are several RCM Analysis tools in common use within Government and industry. The tools are compliant with SAE GEIA-STD-0007, which enables the exchange of Logistics Product Data between the Logistics Product Database and Supportability Analysis tools.

Two tools are highlighted here:

RCM++o Data management and reporting for RCM Analysiso Full-featured FMEA/FMECA functionalityo Maintenance tasks selectiono Optimal interval calculation for preventive repairs/replacemento Cost comparisono Supports industry standards for RCM (e.g., ATA, MSG-3, SAE JA1011

and SAE JA1012) MPC: Maintenance Program Creation Software

o MSG-3-compliant maintenance creator tool for aircraft/aerospace industry

o Analyses included for significant items, functions, failure modes, effects, causes, and tasks


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update


Topic 4: Analysis – Determining Maintenance Tasks and Intervals

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Slide 8-17. Topic 4: Analysis – Determining Maintenance Taks and Intervals



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Slide 8-18. Analysis

During analysis, Reliability Engineers and logisticians determine which option or set of options best prevent failure or reduce its consequences to an acceptable level.

The RCM logic includes a two-step process:

1. Categorize the failure consequencesa. Evident vs. hidden failuresb. Safety/environmentc. Operational (mission) capabilityd. Cost of operations (not including mission impact)

2. Determine the most appropriate and effective maintenance tasks (including appropriate interval) or other action to address consequences


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Slide 8-19. RCM Analysis: Process Map

Maintenance tasks must be both applicable and effective:

Applicable: Does the task address the characteristics of the failure? Each task option has unique criteria that determine if it is applicable.

Effective: How effective is the task in reducing the consequences of the failure? Selection criteria rests on the type of impact—safety/environmental or operational/non-operational.



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Slide 8-20. RCM Analysis: Decision Diagram

The slide highlights three decision points that act as primary drivers in the RCM decision logic tree:

Evident vs. Hidden Failures: Because hidden failures are not apparent to the operator during normal use, analysis takes into account the probability of multiple failures as a result, and the effect of these secondary failures on the system.

Category of Effects: The type of consequence (e.g., safety vs. mission loss) directly impacts trade-off decisions between failure consequences and cost (e.g., safety effects require preventive maintenance).o Note: Categorization of maintenance task risk factors also appears

in operator/maintainer maintenance manuals (e.g., safety consequences are bolded and identified with NOTES, CAUTIONS or WARNINGS).

Task Selection: Failure characteristics drive decisions on the task or group of tasks selected to reduce the risk of failure.


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The RCM decision diagram is where risk management and the ASOE model come together to identify (1) Where is my risk? and (2) How do I address it? You must analyze the data inputs to identify whether the evident or hidden failures impact safety, environment, operation, or economics. Recall from slide 16 that T&E on failure management and operational data are reported through FRACAS, which is the vehicle for data into RCM.

For a complete example of the R C M decision diagram, see MIL-HDBK-2173: Handbook For Reliability-Centered Maintenance Requirements For Naval Aircraft, Weapons Systems And Support Equipment.



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Slide 8-21. Categorizing Consequences: Justifying Preventive Maintenance

Safety/Environmental Consequences

All failure modes that result in potential safety hazards to personnel, equipment, or to the environment (breach of environmental law, regulation, or standard) require mitigation, which may be achieved through preventive maintenance. Run-to-failure, or corrective maintenance, is not permitted for failures with hazardous impacts.

Safety Consequence: Persons severely injured or killed; loss of system Environmental Consequence: Significant, permanent damage to the

environment, or failures that carry penalties

For safety/environmental consequences, the preventive maintenance task must reduce the probability of failure to an acceptable level (Pacc). Then, for the task to be effective, the actual probability of failure given a task must be less than the Pacc. Actual probability of failure is based on initial task intervals and failure distribution.


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Operational/Non-Operational Consequences

In cases where safety is not a consequence, preventive maintenance is justified based on achieving operational capability in the most cost-effective manner. A preventive maintenance task is then desirable if the cost of implementation is less than the cost of run-to-failure:

Impact on operational capability existso The cost for not performing a preventive maintenance task equals

the sum of the cost of operational loss plus failure it prevents (repair costs)

o Inputs: Failure rate, operational consequences, repair and operational costs, real applicable data

Impact is economic onlyo When there is no impact on safety or operations, the consideration

to perform preventive maintenance is purely economic (not including mission impact)

o The cost of the task must be less than the cost of the failure it prevents (repair costs)

Note: When performing an economic trade-off, such as cost-benefit ratio, normalize the cost to a common unit of measurement across maintenance options (hours, cycles). Also, include variables such as peacetime versus wartime/operational tempo.



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Slide 8-22. On-Condition Maintenance: Predictive Maintenance

On-condition maintenance is performed at the most appropriate time based on the actual condition (evidence of need) of the equipment, rather than a scheduled or planned maintenance action regardless of need.

With this maintenance strategy, equipment performance is compared against known standards and criteria. If the inspection reveals performance outside the healthy range, the potential for failure exists. Early indications of failure or impending failure allow for effective and timely response before functional failures occur. If the inspection does not indicate a potential failure, no action is required and the item continues until the next inspection.

Inspections are often geared to life limiting wear. In the example of the tire, the limitation is tread, which if worn too much (past the head of Abraham Lincoln on a penny), can pose a safety issue.


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Slide 8-23. On-Condition Maintenance: The P-to-F Curve

On-condition maintenance is predictive in nature. The inspection detects Potential Failure (PF) conditions and then predicts the remaining useful life before a Function Failure (FF).

The time between detection of PF and FF (PF Curve) is the opportunity to conduct on-condition inspections.

The PF curve is based on progression of failure once failure begins, not the failure rate/probability of failure.

RCM Analysis provides evidence of need (failure condition) and a PF curve that together determine the most appropriate time to perform maintenance.

Choosing the Appropriate Potential Failure Condition

Multiple degradation characteristics are possible. Therefore, consider the following when selecting a condition to monitor:

Choose those conditions that are achievable/consistent with detection methods

Consider whether the length and consistency of the P to F curve between PF/FF is long enough to perform inspections or manage the consequences of failure

Consider the availability of equipment to perform the maintenance task Consider the cost-effectiveness of the on-condition task



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Examples of On-Condition Maintenance Methods and Tools

On-condition maintenance methods and tools include inspections, detection through human senses, sophisticated monitoring equipment, and continuous monitoring by sensors applied directly to equipment. Examples include:

Visual/non-destructive inspection Vibration monitoring and analysis Oil sample analysis Brake-pad measurements

Applicability of the Task

A task could be selected for on-condition maintenance if it meets the following requirements:

Possible to define potential failure characteristics Possible to detect failure with explicit task Consistent PF interval It is practical to monitor condition at intervals at or less than PF interval PF interval is long enough to manage consequences to failure

Determining the Appropriate Interval

Periodic or continuous assessment of equipment condition occurs at one or more intervals between PF and FF, with frequency based on:

Consequences of failure Effectiveness of task Accessibility of item Skill of personnel performing inspection Industry standards Specific system

Cost Formula

Cost of 1 inspection * Man-hours * Cost of Materials

Note: Assumes field maintenance


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Slide 8-24. On-Condition Maintenance: CBM+ and Prognostics and Health Management (PHM)

Condition-Based Maintenance Plus (CBM+) optimizes on-condition maintenance by providing more accurate and efficient real-time condition data, fault identification, and failure prediction. To do this, CBM+ integrates a comprehensive set of modern technology, tools, and processes, including:

Hardware Software Design Processes Communications Tools

Typically implemented at the design stage, a CBM+ strategy requires greater up-front investment, skill level, and time. Applicability rests on several factors:

System/component maturity and complexity Resource Availability Cost-benefit analysis Operational performance and experience in the field (e.g., frequency

and impact of failure modes)



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CBM+ Relationship to RCM Analysis

CBM+ expands RCM Analysis by providing additional tools, technologies, and processes to determine the most appropriate maintenance task.

RCM Analysis may suggest a revision to a maintenance task or redesign. At that point CBM+ may be considered (e.g., sensor, diagnostic software).

Diagnostics in CBM+

CBM+ provides diagnostic tools to compare current health conditions against known fault conditions to determine the state of a component to perform its function. Monitoring/recording devices and analysis software are used to:

Detect failures or potential failures Assess degree of degradation Signal need for maintenance Identify root causes and design fixes Assess impact on mission Collect, store, and communicate system condition and failure data

Prognostics in CBM+

CBM+ also predicts future health and the remaining life of equipment through processes that:

Anticipate faults, problems, potential failures, and required maintenance actions

Determine lead time from detecting a failure condition to actual functional failure

Indicate out of range conditions, imminent failure probability, and proactive maintenance actions through monitoring devices/software

Improve accuracy and efficiency of failure detection


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Health Management in CBM+

Integrated Information Systems allow LCLs to capture, track, and analyze the health and status of systems. Acting on condition information provided by diagnostic and prognostic data, LCLs can predict when failures may occur and determine appropriate maintenance and other logical actions consistent with operational demand and available resources.

CBM+ health management involves:

User alerts Data mining and analysis Simulation and modeling Decision-support systems



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Slide 8-25. CBM+ and PHM: Impact on Supportability

CBM+ supports data collection, analysis, and decision-making for successful acquisition, Sustainment, and operations. As a result, CBM+ has multiple impact points on Supportability and Supportability Analysis:

Improves Operational Availabilityo Identifies optimum time to perform required maintenance

Extends equipment life Decreases down time due to maintenance Decreases the number of non-mission capable items

Improves maintenance effectivenesso More appropriate, effective, and timely maintenance actionso Greater accuracy in predicting failures improves planningo Shorter maintenance cycleso Increased quality of processo Fewer unscheduled repairso Fewer unnecessary maintenance tasks


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Content Reduces Mean Down Time

o Provides real-time maintenance information and accurate technical data that: Accelerates repair and support processes Accelerates return to operational status

Reduces overall logistics footprinto Reduced maintenance-related requirements (manpower, spares,

facilities, equipment, etc.) Reduces O&S Costs

o Fewer unscheduled and unnecessary repairso Maintenance performed at optimum timeo Accurate failure prediction leads to streamlined supply chain

operations by reducing downtime, labor needso Informs resource planning, force planning, situational assessments



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Slide 8-26. Interval-based Tasks: Overview

Interval-based maintenance tasks are regularly scheduled maintenance, performed regardless of equipment condition.

Preventive maintenance is applicable to items that:o Are consumableo Are subject to wear out (including chemical breakdown)o Demonstrate a known failure pattern (i.e., statistical failure

information provides a fixed schedule for overhaul) Maintenance interval is determined by failure rate (MTBF)/probability

of failure (represented in time based on cycles, hours, etc.) Types of scheduled maintenance

o Servicing and lubrication (includes filtration, such as changing air/oil filters)

o Calibrationo “Hard Time" removal/replacemento Failure finding


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Slide 8-27. Interval-Based Tasks: Overview, continued

This is an example of a typical maintenance schedule for a car engine. Notice the tasks inserted at specific maintenance intervals:

I = Inspect, correct, replace R = Replace



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Slide 8-28. Servicing/Lubrication Tasks: Interval-Based Maintenance

Servicing

Servicing tasks replenish consumables expended during normal operation, such as fuel, oil, oxygen, and nitrogen.

Applicability of tasko Required by system design or operational needs based on usage,

environment, and convenience Intervals

o Scheduled according to needo Assign conservative interval at convenient point in maintenance

program Inputs

o Equipment designso Original Equipment Manufacturer (OEM) specificationso Operator/maintainer inputso Maintenance publications


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Lubrication

Lubrication reduces friction, protects against wear, removes dust and debris, prevents rust and corrosion, provides a seal for gases, and prevents burning.

Applicability of tasko Required when lubricant is non-permanent and therefore needs

periodic reapplication Intervals

o Scheduled based on predicted or measured life of lubricant, usage, and operational environment

Inputso Equipment drawingso OEMo Maintenance publicationso Operator/maintainer inputo Lubricant manufacture date

Cost for Servicing and Lubrication

One servicing/lubrication task = Man-hours to perform + Cost per man-hour + Cost of materials



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Slide 8-29. Hard Time Remove/Replace: Interval-Based Maintenance

Hard time maintenance is scheduled removal for rework/restoration or discard/replace, and is performed at a predetermined, maximum age, even with no failure pending.

Applicability of tasko Possible to identify characteristics of wear-out, which are sudden

increase in probability of failure with operating ageo Items can survive to useful lifeo On-condition maintenance is not applicable or effective:

Failure does not have detectable or predictable failure condition Failure does not allow long enough PF interval to permit

effective on-condition task


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o Safe life limit: Used for safety/environmental consequences Limit below which no failure will occur Probability of failure is less than acceptable probability of failure

o Economic life limit: When the cost is less than or the same as run-to-failure Maximizes useful life Adds risk for occasional failure

o Reliability requirement Inputs

o Weibull analysiso Fatigue analysis or testso Manufacturers recommended service lifeo Existing effective maintenance tasko Engineering judgment based on data, operators/maintainers, similar

components Cost formula

o (Man-hours * cost per man-hour) + cost of materials



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Slide 8-30. Hard Time Remove/Replace: Water Pump Example

This graph charts the Reliability of a single car's water pump again distance travelled. This is probability - taking a normal distribution, but looking at one tail. Unreliability equals 1 minus Reliability.

At which point should you take your car in to change the water pump?


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Slide 8-31. Economic Remove/Replace: Water Pump Example

This graph plots the cost of replacing the water pump against distance travelled. Here, the most economical point to replace the water pump is at 100,000 kilometers. However, is this the optimal remove/replace point?



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Slide 8-32. Hard Time Remove/Replace: Water Pump Example, continued

Water pump failure results in severe engine damage or engine failure, as major engine components overheat and seize.

The Safe Life Limit is chosen well before the probability of Wear Out. The Economic Life Limit takes into consideration useful life and costs of

deferring repairs, when roadside assistance and special repairs away from home are needed should failure occur.

Wear Out spans about 5,000 km (96,000 – 100,000 km), a zone where failure is imminent and costly.

The takeaway: Replace at the Safe Life Limit of 96,000 km, where the water pump meets a minimum Reliability of 85%.


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Slide 8-33. Failure Finding Inspections: Interval-Based Maintenance

Failure finding tasks are appropriate when the occurrence of a functional failure is not evident to the operator during normal use. Hidden failures require regularly scheduled inspection tasks to reduce the risk of multiple failures to an acceptable level.

Evident Failure—The failure is apparent on its own, under normal conditions; no other action needed to detect (e.g., visual, audio, or operational warnings, such as loss of control)

Hidden Failure—The operator has to perform any action, not within normal operating procedures, to detect the failure

Applicability of Task

Only when on-condition maintenance, hard time maintenance, or a combination of both are not applicable or effective for hidden failures

There is no way for operator/maintainer to know of failure through indicators/alarms

Failure would result in critical situation should another failure occur as a result

Built in redundancy exists Alternative to redesign Failure already occurred



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Interval

Part of pre- and post-mission inspection checklists

Cost Formula

(Man-hours * cost per man-hour) + material cost


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Slide 8-34. Run-to-Failure: Corrective Maintenance

A decision to run-to-failure (RTF) allows the failure to occur, followed by corrective action to repair or replace the item. This type of maintenance is unscheduled and unplanned.

Applicability of tasko Operational/economic failures onlyo When consequences of failure are tolerableo Redundancy existso Non-critical/inconsequential failureo Unlikely to failo No historical datao Small items

Costo Average repair cost of itemo Cost of secondary damageo Cost of multiple failures, if hidden FFo Cost of loss of operations, if applicable



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Slide 8-35. Run-to-Failure: Water Pump Example

Not all RCM Analyses are applicable to run-to-failure. In this example, the water pump is not a candidate for a run-to-failure task because risk/cost of run-to-failure far outweighs the cost of removal and replacement.


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Slide 8-36. Other Logical Actions

When run-to-failure is not the chosen outcome, but no appropriate preventive maintenance task reduces the consequences of functional failure to an acceptable level, other actions may mitigate failure consequences.

Possible actionso “Root cause” analysiso Redesign (accessibility, modularity, testability)

Improvement in Reliability Incorporation of Prognostic Health Management (PHM) Establishing redundancy

o Operational restrictionso Change in maintenance procedureso Additional data collectiono Change to training programo Change to emergency procedureso Change to supply systemo Change to technical manuals

Applicability of tasko Positive return on investment (ROI) on Availability, cost, and

reduced exposure to hazardous conditions Cost: Development and implementation costs



Topic 5: Report Findings – Data Management and Communication Paths

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Slide 8-37. Topic 5: Report Findings – Data Management and Communication Paths


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Slide 8-38. Report Findings

In the Report Findings step, an RCM Analysis summary report is submitted to the IPT for approval. Tasks are then packaged for inclusion in the MTA process.



Slide 8-39. Report & Implement Findings

Recall the RCM Analysis process chart. At this stage, the data is reviewed, approved by the IPT, and then inputted directly into MTA.

Conducted by the Life Cycle Logistician (LCL), MTA evaluates the Logistics Product Data. The results of this evaluation can reveal system design, component attributes, or maintenance processes that contribute to failing to meet Availability and Reliability requirements. It can also identify resource shortages.


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SAE GEIA-STD-0007


Slide 8-40. RCM Analysis Report

The RCM Analysis report includes the following summary:

List of significant items, categorized by consequence (safety, environmental, operational, economic)

Functional failure analysis (function, failure mode, failure effect, failure cause)

Evident/hidden failures Task selection for each cause of each failure (question tree/answers/

intervals Maintenance task summary

Note: Recall that all maintenance not identified by RCM is corrective action (run-to-failure), by default.



Slide 8-41. Map Failure Modes to Tasks

RCM Analysis outputs become inputs into MTA; MTA updates the Logistics Product Database with maintenance tasks and subtasks.

Packaging Tasks for Input into MTA

Maintenance task recommendations are packaged for input into the subsequent Maintenance Task Analysis (MTA). The work package includes:

Interval-based/scheduled tasks and frequencies/intervals (preventive maintenance)

On-condition/CBM+ tasks and frequencies/intervals (predictive maintenance)

Other recommended tasks to effectively avoid, predict, and mitigate consequences of failure

Cautions and Warnings for maintenance tasks related to safety


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Packaging Process

1. Confirm tasks were analyzed using the proper metrics2. Structure tasks along timeline3. Identify logical task groupings

o Common inspection intervalso Common panel accesso Common skill and maintenance levelso Determine which tasks are least flexible in adjustment

4. Develop final packagingo Package in phaseso Package with other maintenance for convenienceo Fit into existing packageso Repackaging: review of preventive maintenance tasks package

Assembling maintenance tasks into work packages minimizes equipment downtime and reduces the cost of implementing and performing maintenance by performing multiple tasks together.



Slide 8-42. Inspect UAV SATCOM Control Task

When a new task is designated by RCM Analysis, the LCL coordinates with the applicable IPT for the analysis outcome to be entered into the Logistics Product Database as an initial task or update to an existing task as part of the Maintenance Task Analysis (MTA).

The task includes:

Task Frequency—Hours, cycles, calendar time, pre/post operation (not shown on graph)

Task Code—SAE GEIA-STD-0007 Code detailed in Lesson 9, MTA. Subtask Identification—Descriptive subtitle; e.g., CAUTION, INSPECT Subtask Number—Task Step Number Sequential Subtask Description—Task Step Narrative Predicted Mean Elapsed Time—The average time in minutes for a

maintenance tech to complete the task step Resources—Technician, tools, test equipment and facility

The RCM Analysis outcome could impact any or all of the item’s Maintenance Task Analysis requirements.


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Slide 8-43. RCM Analysis Results: IPT Communication Paths

RCM Analysis acts as the boundary between Reliability Engineering and maintenance, and therefore has possible impact on all Integrated Product Support Elements. The RCM Analysis functional lead must understand both areas in order to work effectively with the Product Support Management IPT and to effectively provide inputs to the Maintenance Task Analysis activity.

As issues arise due to RCM Analysis, such as possible redesign or trade-off decisions between maintenance recommendations, the IPT taking action:

Determines team member responsibilities—designates lead and supporting membership if forming a WIPT to resolve the issue

Makes recommendations—forms applicable failure consequences, maintenance task, and interval failure mitigation strategies

Coordinates solutions—implements goals and objectives through program and IPT leadership



The slide highlights two scenarios:

Technical Data: Changing an existing maintenance task, such as an intervalo Systems Engineering IPTo Product Support Management IPT

Maintenance Planning & Management: Adding a new maintenance tasko Test & Evaluation IPTo Systems Engineering IPTo Product Support Management IPT


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Topic 6: Exercise and Simulation

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Slide 8-44. Topic 6: Exercise and Simulation



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Slide 8-45. Exercise and Simulation Overview


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Slide 8-46. Exercise



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Slide 8-47. Simulation


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Topic 7: Summary

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Slide 8-48. Topic 7: Summary



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Slide 8-49. Takeaways


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Slide 8-50. Summary

Congratulations! You have completed Lesson 8: Reliability Centered Maintenance Analysis.


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