LOG 211 Supportability Analysis

Student Guide

Log 211 Supportability Analysis

Student Guide

Reliability Centered Maintenance Analysis

Content

Slide 81. Lesson 8: Reliability Centered Maintenance Analysis

Welcome to Lesson 8: Reliability Centered Maintenance Analysis.

Introduction

Content

Slide 82. Topic 1: Introduction

Content

Technology Maturation & Risk Reduction

Slide 83. 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:

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

How often is maintenance performed?

What resources are required?

What source data is required for the development of technical manuals?

Level of Repair Analysis (LORA), which determines:

At what echelon of maintenance are the tasks performed?

What are the Operation & Support (O&S) Costs of the tasks?

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 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).

Content

Slide 84. 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?

Content

Slide 85. Topics and Objectives

Overview of RCM Analysis

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Slide 86. Topic 2: Overview of RCM Analysis

Slide 87. 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).

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.

Content

Slide 88. 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?

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.

Content

Slide 89. 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.

Content

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.

Content

Slide 810. 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:

Reliability

Availability

Maintainability

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

RCM Analysis Impact on Mission Effectiveness

Increases maintenance efficiency

Greater productivity

Shorter maintenance cycles

Increased quality of process

Better use of resources

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

Content

Slide 811. 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 812. What is RCM Analysis: Inputs and Outputs

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

Set Up – Building a Plan and Gathering Inputs

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Slide 813. Topic 3: Set Up – Building a Plan and Gathering Inputs

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Slide 814. 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.

Content

SAE GEIA-STD-0007

Slide 815. 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:

Program Manager—Program Manager responsibilities with regards to RCM Analysis are to plan, develop, program, and implement RCM processes and outputs.

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

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 metrics

Business: ROI/cost-benefit for initial RCM Analysis and Sustainment

Program management: training, schedules, number of systems analyzed, etc.

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

Content

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

Content

SAE GEIA-STD-0007

Slide 816. Determine Data Inputs

RCM Analysis Data Inputs

Design characteristics

Capability Development Document (CDD)

Built In Test (BIT)

Sensors

System configuration

Engineering data, studies, and drawings

Design reports

Product specification sheets

Production inspection records

Vendor information

Original Equipment Manufacturer (OEM)

Developmental testing results

Test result reports

Engineering investigation reports

Modeling and simulation data

Subject matter experts with knowledge of equipment and operating context

Operator

Maintainer

In-service engineer

Technical representative

Program Manager

Reliability analyses

Reliability characteristics

Time to Failure (calculated or estimated) for non-reparable items

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)

Reliability Block Diagrams

Failure characteristics

Potential failure conditions

Failure distribution curve (calculated or estimate)

Wear out/life limit age

Random failures

Failure mode occurring within service life of equipment

Test data

Maintainability analyses

Mean Time Between Maintenance (MTBM)

Mean Time to Repair (MTTR)

Mean Down Time (MDT)

Mean Repair Time (MRT)

Maintenance Task Analysis

Maintainability: Engineering Considerations

Accessibility

Modularity

Testability

Built In Test architecture

Ambiguity groups/BIT effectiveness/detection rates/false reports

Failure Mode Effects and Criticality Analysis (FMECA) results

Functions, functional failures, failure modes, failure effects

Severity class for failure mode (criticality)

Fault Tree Analysis (FTA) results

Human Systems Integration (safety and hazard analysis)

Maintenance data systems

Previous maintenance plans

In-service performance data

Item repair histories

Failure Reporting, Analysis, and Corrective Action System (FRACAS)

FRACAS is system of reporting and analyzing failures, recommending corrective action

Developed from Test & Evaluation (T&E) events and field failure/repairs

Common data captured in FRACAS include field MTTR, MTBF, Reliability growth, failure analysis (incident, type, location, root cause, etc.)

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++

Data management and reporting for RCM Analysis

Full-featured FMEA/FMECA functionality

Maintenance tasks selection

Optimal interval calculation for preventive repairs/replacement

Cost comparison

Supports industry standards for RCM (e.g., ATA, MSG-3, SAE JA1011 and SAE JA1012)

MPC: Maintenance Program Creation Software

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

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

Analysis – Determining Maintenance Tasks and Intervals

Content

Slide 817. Topic 4: Analysis – Determining Maintenance Taks and Intervals

Content

Slide 818. 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 consequences

Evident vs. hidden failures

Safety/environment

Operational (mission) capability

Cost of operations (not including mission impact)

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

Content

Slide 819. 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.

Content

Slide 820. 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).

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.

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.

Content

Slide 821. 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.

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 exists

The cost for not performing a preventive maintenance task equals the sum of the cost of operational loss plus failure it prevents (repair costs)

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

Impact is economic only

When there is no impact on safety or operations, the consideration to perform preventive maintenance is purely economic (not including mission impact)

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.

Content

Slide 822. 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.

Slide 823. 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

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

Content

Slide 824. 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)

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

Content

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

Content

Slide 825. 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 Availability

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 effectiveness

More appropriate, effective, and timely maintenance actions

Greater accuracy in predicting failures improves planning

Shorter maintenance cycles

Increased quality of process

Fewer unscheduled repairs

Fewer unnecessary maintenance tasks

Reduces Mean Down Time

Provides real-time maintenance information and accurate technical data that:

Accelerates repair and support processes

Accelerates return to operational status

Reduces overall logistics footprint

Reduced maintenance-related requirements (manpower, spares, facilities, equipment, etc.)

Reduces O&S Costs

Fewer unscheduled and unnecessary repairs

Maintenance performed at optimum time

Accurate failure prediction leads to streamlined supply chain operations by reducing downtime, labor needs

Informs resource planning, force planning, situational assessments

Content

Slide 826. Interval-based Tasks: Overview

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

Preventive maintenance is applicable to items that:

Are consumable

Are subject to wear out (including chemical breakdown)

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

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

Calibration

“Hard Time" removal/replacement

Failure finding

Content

Slide 827. 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

Content

Slide 828. Servicing/Lubrication Tasks: Interval-Based Maintenance

Servicing

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

Applicability of task

Required by system design or operational needs based on usage, environment, and convenience

Intervals

Scheduled according to need

Assign conservative interval at convenient point in maintenance program

Inputs

Equipment designs

Original Equipment Manufacturer (OEM) specifications

Operator/maintainer inputs

Maintenance publications

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 task

Required when lubricant is non-permanent and therefore needs periodic reapplication

Intervals

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

Inputs

Equipment drawings

OEM

Maintenance publications

Operator/maintainer input

Lubricant manufacture date

Cost for Servicing and Lubrication

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

Content

Slide 829. 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 task

Possible to identify characteristics of wear-out, which are sudden increase in probability of failure with operating age

Items can survive to useful life

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

Intervals

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

Economic life limit: When the cost is less than or the same as run-to-failure

Maximizes useful life

Adds risk for occasional failure

Reliability requirement

Inputs

Weibull analysis

Fatigue analysis or tests

Manufacturers recommended service life

Existing effective maintenance task

Engineering judgment based on data, operators/maintainers, similar components

Cost formula

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

Content

Slide 830. 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?

Content

Slide 831. 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?

Content

Slide 832. 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%.

Content

Slide 833. 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

Interval

Part of pre- and post-mission inspection checklists

Cost Formula

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

Content

Slide 834. 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 task

Operational/economic failures only

When consequences of failure are tolerable

Redundancy exists

Non-critical/inconsequential failure

Unlikely to fail

No historical data

Small items

Cost

Average repair cost of item

Cost of secondary damage

Cost of multiple failures, if hidden FF

Cost of loss of operations, if applicable

Content

Slide 835. 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.

Content

Slide 836. 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 actions

“Root cause” analysis

Redesign (accessibility, modularity, testability)

Improvement in Reliability

Incorporation of Prognostic Health Management (PHM)

Establishing redundancy

Operational restrictions

Change in maintenance procedures

Additional data collection

Change to training program

Change to emergency procedures

Change to supply system

Change to technical manuals

Applicability of task

Positive return on investment (ROI) on Availability, cost, and reduced exposure to hazardous conditions

Cost: Development and implementation costs

Report Findings – Data Management and Communication Paths

Content

Slide 837. Topic 5: Report Findings – Data Management and Communication Paths

Content

Slide 838. 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.

SAE GEIA-STD-0007

Slide 839. 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.

Slide 840. 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 841. 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

Packaging Process

1. Confirm tasks were analyzed using the proper metrics

Structure tasks along timeline

Identify logical task groupings

Common inspection intervals

Common panel access

Common skill and maintenance levels

Determine which tasks are least flexible in adjustment

Develop final packaging

Package in phases

Package with other maintenance for convenience

Fit into existing packages

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 842. 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.

Slide 843. 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 interval

Systems Engineering IPT

Product Support Management IPT

Maintenance Planning & Management: Adding a new maintenance task

Test & Evaluation IPT

Systems Engineering IPT

Product Support Management IPT

Exercise and Simulation

Content

Slide 844. Topic 6: Exercise and Simulation

Content

Slide 845. Exercise and Simulation Overview

Content

Slide 846. Exercise

Content

Slide 847. Simulation

Summary

Content

Slide 848. Topic 7: Summary

Content

Slide 849. Takeaways

Content

Slide 850. Summary

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

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January 2013

Final v1.3

January 2013

Final v1.3

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