rcm fmeca.ppt

FAILURE MODE, EFFECTS, FAILURE MODE, EFFECTS, AND CRITICALITY ANALYSIS AND CRITICALITY ANALYSIS

(FMECA)(FMECA)

FAILURE MODE, EFFECTS, FAILURE MODE, EFFECTS, AND CRITICALITY ANALYSIS AND CRITICALITY ANALYSIS

(FMECA)(FMECA)

Module 4Module 4

UNIT IIUNIT II

RCM PROCESSRCM PROCESSRCM PROCESSRCM PROCESS

"Copyright 2002, Information Spectrum, Inc. All Rights Reserved."

• IntroductionIntroduction• IntroductionIntroduction

Module Preview:Module Preview:Module Preview:Module Preview:

• FMECAFMECA• FMECAFMECA

IntroductionIntroductionIntroductionIntroduction

• ReferencesReferences• ReferencesReferences

FAILURE MODE, EFFECTS, AND FAILURE MODE, EFFECTS, AND CRITICALITY ANALYSIS CRITICALITY ANALYSIS (FMECA)(FMECA)


• Review and SummaryReview and Summary• Review and SummaryReview and Summary

Module Objective:Module Objective:Module Objective:Module Objective: IntroductionIntroductionIntroductionIntroduction

1. Introduce the concept of Failure Mode, 1. Introduce the concept of Failure Mode, Effects, and Criticality Analysis (FMECA). Effects, and Criticality Analysis (FMECA).

2. Define the following FMECA terms:2. Define the following FMECA terms: FunctionFunction Functional FailureFunctional Failure Failure ModeFailure Mode Failure EffectFailure Effect Failure DetectionFailure Detection Severity ClassificationSeverity Classification Mean Time Between Failure (MTBF)Mean Time Between Failure (MTBF)

3. Identify FMECA reference materials3. Identify FMECA reference materials



1. Identify Team and responsibilities 4. Identify and document Review Process2. Identify analysis items 5. Orientation/Training3. Prioritize Items 6. Ground Rules and Assumptions

PLANNING AND PREPARATION

ANALYSIS

RCM ProcessRCM ProcessRCM ProcessRCM Process

AnalysisAnalysisApproacApproach/ RCM h/ RCM PlanPlan

AnalysisAnalysisApproacApproach/ RCM h/ RCM PlanPlan

MaintenanceMaintenanceRequirementsRequirements

MaintenanceMaintenanceRequirementsRequirements

Maintenance Maintenance ProgramProgram

Maintenance Maintenance ProgramProgram

DataDataDataData

1. Equipment Kick-off Meeting2. Initial Data Gathering3. Hardware Partition4. Function5. Functional Failure6. Failure Mode7. Failure Effects8. Failure Consequences9. Task Evaluation10. Task Selection

1. Package Maintenance Task2. Implement Other Actions

ResultsResults

IMPLEMENT RESULTS

1. Emergent Issues2. Age Exploration3. Hardware Changes4. Trend/degrader analysis5. Document Reviews

SUSTAIN

FMECAFMECAFMECAFMECA

FMECA

FMECA Definition:FMECA Definition:FMECA Definition:FMECA Definition:Process used to determine the functions, Process used to determine the functions, functional failures, and failure modes of functional failures, and failure modes of equipment; and the associated effects, severity, equipment; and the associated effects, severity, and frequency of each failure modes:and frequency of each failure modes:

Steps involve identifying... Steps involve identifying... • FunctionsFunctions• Functional FailuresFunctional Failures• Failure ModesFailure Modes• Failure Effects Failure Effects • Severity of Failure effectsSeverity of Failure effects• Frequency of occurrenceFrequency of occurrence

… … as they apply to the equipment under as they apply to the equipment under analysis in its operating contextanalysis in its operating context




FMECA Terms:FMECA Terms:FMECA Terms:FMECA Terms:

Hydraulic PumpAssembly

FUNCTIONFUNCTIONWhat the user expects the asset or system to do What the user expects the asset or system to do within a required standard of performance.within a required standard of performance.

Provides hydraulic Provides hydraulic fluid at a pressure fluid at a pressure of 3000 psi +/- 200 of 3000 psi +/- 200 psipsi




Consider all functions of an itemConsider all functions of an item

Describe functions in terms of specific Describe functions in terms of specific limits when possiblelimits when possible

State functions in terms of what the item State functions in terms of what the item is needed for, not its capability is needed for, not its capability

Do not combine functionsDo not combine functions

• Function descriptions should include a Function descriptions should include a verb, object, and applicable limitsverb, object, and applicable limits

Identifying FunctionsIdentifying Functions:Identifying FunctionsIdentifying Functions: FMECAFMECAFMECAFMECA



All equipment has primary and secondary All equipment has primary and secondary functionsfunctions

FMECA for RCM analysis should identify ALL FMECA for RCM analysis should identify ALL primary AND secondary functions. Typical primary AND secondary functions. Typical Secondary Functions: Secondary Functions:

ControlControl Warning or status indicationWarning or status indication Environmental protectionEnvironmental protection Physical support or attachmentPhysical support or attachment Safety or protective functionsSafety or protective functions Fluid Containment Comfort and Aesthetics

Identifying Functions:Identifying Functions:Identifying Functions:Identifying Functions: FMECAFMECAFMECAFMECA




Function sources:Function sources:

Maintenance Manual description/theory Maintenance Manual description/theory of of operation operation Operating ManualsOperating Manuals Other tech data providing system Other tech data providing system

descriptions descriptions

Common Errors: Common Errors: Missing secondary functions Missing secondary functions Listing functions of lower level hardwareListing functions of lower level hardware

itemsitems



NAVAIR 00-25-403 RCM adds a NAVAIR 00-25-403 RCM adds a categorization process to function categorization process to function identification called “identification called “significant function significant function identificationidentification””

• Intended to: Intended to:

1)1) eliminate analysis of inconsequential eliminate analysis of inconsequential functions functions

2)2) Ensure all significant functions are Ensure all significant functions are identifiedidentified

• Not technically part of the FMECA processNot technically part of the FMECA process




A SIGNIFICANT FUNCTION is one whose failure A SIGNIFICANT FUNCTION is one whose failure will have adverse effect on the end item with will have adverse effect on the end item with respect to:respect to:

• SafetySafety

• Environmental HealthEnvironmental Health

• OperationsOperations

• EconomicsEconomics




SIGNIFICANT FUNCTION (SF) IDENTFCATIONSIGNIFICANT FUNCTION (SF) IDENTFCATIONSIGNIFICANT FUNCTION (SF) IDENTFCATIONSIGNIFICANT FUNCTION (SF) IDENTFCATION

FUNCTION

SIGNIFICANTSIGNIFICANTFUNCTIONFUNCTION

NON-SIGNIFICANTNON-SIGNIFICANTFUNCTIONFUNCTION

YESYES

YESYES

YESYES

YESYES

NONO

NONO

NONO

NONO

DOES THE LOSS OF FUNCTION DOES THE LOSS OF FUNCTION HAVE AN ADVERSE EFFECT ON HAVE AN ADVERSE EFFECT ON

SAFETY OR ENVIRONMENT?SAFETY OR ENVIRONMENT?

DOES THE LOSS OF FUNCTION DOES THE LOSS OF FUNCTION HAVE AN ADVERSE EFFECT ON HAVE AN ADVERSE EFFECT ON

OPERATIONS?OPERATIONS?

DOES THE LOSS OF FUNCTION DOES THE LOSS OF FUNCTION HAVE AN ADVERSE ECONOMIC HAVE AN ADVERSE ECONOMIC

IMPACT?IMPACT?

IS THE FUNCTION PROTECTED BYIS THE FUNCTION PROTECTED BYAN EXISTING PM TASK?AN EXISTING PM TASK?

FUNCTIONFUNCTION

5 Fly-ins5 Fly-ins

Class ExerciseClass ExerciseFMECAFMECAFMECAFMECA

Objective:Objective:List the functions of List the functions of

a Coffee Makera Coffee Maker

Identifying Functions:Identifying Functions:Identifying Functions:Identifying Functions:



Function Function Exercise:Exercise:Function Function Exercise:Exercise:

3 Fly Ins

HOT PLATE HOT PLATE SUBSYSTEMSUBSYSTEM

1B41B4

PWR SWITCH PWR SWITCH SUBSYSTEMSUBSYSTEM

1B11B1

CLOCK CLOCK PROGRAMMEPROGRAMMER SUBSYSTEMR SUBSYSTEM

1B21B2

WATER WATER HEATING HEATING

SUBSYSTEMSUBSYSTEM

1B3

FILTRATION FILTRATION SUBSYSTEMSUBSYSTEM

1A21A2

CARAFE CARAFE SUBSYSTEMSUBSYSTEM

1A31A3

WATER WATER RESERVOIR RESERVOIR SUBSYSTEMSUBSYSTEM

1A11A1

COFFEE COFFEE MAKERMAKER

11

ELECTRICAL ELECTRICAL SYSTEMSYSTEM

1B1B

BREWING BREWING SYSTEMSYSTEM

1A1A

Analyze at Analyze at this levelthis level

Analyze at Analyze at this levelthis level

Remember Secondary Functions: Remember Secondary Functions: ControlControl Warning or status indicationWarning or status indication Environmental protectionEnvironmental protection Physical support or attachmentPhysical support or attachment Safety or protective functionsSafety or protective functions Fluid Containment Comfort and Aesthetics

Function Exercise:Function Exercise:Function Exercise:Function Exercise:

Coffee Maker Coffee Maker FunctionsFunctions

1.1. Brew 1 to 12 cups of coffee Brew 1 to 12 cups of coffee

2.2. Maintain coffee at 120°f Maintain coffee at 120°f 5°f 5°f

3. Automatically start brewing process within 15 3. Automatically start brewing process within 15 minutes of time specified by userminutes of time specified by user

4. Automatically shut down coffee maker 4 4. Automatically shut down coffee maker 4 hours after brew cycle is completedhours after brew cycle is completed

5. 5. Contain coffee in carafeContain coffee in carafe

6. Contain 1 carafe of water in reservoir6. Contain 1 carafe of water in reservoir

7. Provides safe handling of hot coffee7. Provides safe handling of hot coffee




Fails to provide Fails to provide hydraulic fluid at hydraulic fluid at a pressure of a pressure of 3000 psi +/- 200 3000 psi +/- 200 psipsi

Hydraulic PumpHydraulic PumpAssemblyAssembly

FUNCTIONAL FAILUREFUNCTIONAL FAILUREThe inability of an item to perform a The inability of an item to perform a specific function within specified limits.specific function within specified limits.




Note that functional failure may not be a Note that functional failure may not be a complete loss of the functioncomplete loss of the function

Separate functional failures should be listed Separate functional failures should be listed where the effects of less than total loss of where the effects of less than total loss of the function are different from total lossthe function are different from total loss

Ensure functional failure addresses the Ensure functional failure addresses the function as definedfunction as defined

Common Errors:Common Errors:- - Confusion with failure modes of Confusion with failure modes of

hardwarehardware- Confusion with potential failures- Confusion with potential failures

Identifying Functional Failures:Identifying Functional Failures:Identifying Functional Failures:Identifying Functional Failures: FMECAFMECAFMECAFMECA



Identifying FMECA Terms:Identifying FMECA Terms:Identifying FMECA Terms:Identifying FMECA Terms: FMECAFMECAFMECAFMECA

Class ExerciseClass Exercise

Objective:Objective:

Identify and list the coffee Identify and list the coffee maker’s maker’s

Functional FailuresFunctional Failures



FUNCTION 1 FUNCTION 1 – Brew 1 to 12 cups of coffee– Brew 1 to 12 cups of coffee

FUNCTIONAL FAILURE A - Fails to brew coffeeFUNCTIONAL FAILURE A - Fails to brew coffee

FUNCTION 2 FUNCTION 2 - Maintain coffee temperature at 120°f - Maintain coffee temperature at 120°f 5° f 5° f

FUNCTIONAL FAILURE A – Doesn't keep coffee warm(< 100°f)FUNCTIONAL FAILURE A – Doesn't keep coffee warm(< 100°f)

FUNCTIONAL FAILURE B – Heats Coffee too hot (>125° f)FUNCTIONAL FAILURE B – Heats Coffee too hot (>125° f)

FUNCTIONAL FAILURE C – Partial warm coffee (>100FUNCTIONAL FAILURE C – Partial warm coffee (>100°f°f but < than but < than 115°f)115°f)

Coffee Maker Coffee Maker Functional FailuresFunctional Failures



FUNCTION 3 FUNCTION 3 - Automatically brew coffee within 15 minutes of - Automatically brew coffee within 15 minutes of time specified by usertime specified by user

FUNCTIONAL FAILURE A - Does not brew coffee at allFUNCTIONAL FAILURE A - Does not brew coffee at all

FUNCTIONAL FAILURE B - Brews coffee more than 15 minutes earlier FUNCTIONAL FAILURE B - Brews coffee more than 15 minutes earlier than specifiedthan specified

FUNCTIONAL FAILURE C - Brews coffee more than 15 minutes after FUNCTIONAL FAILURE C - Brews coffee more than 15 minutes after time specified by usertime specified by user

Coffee Maker Coffee Maker Functional FailuresFunctional Failures




FAILURE MODEFAILURE MODEA specific physical condition that causes a A specific physical condition that causes a particular functional failure.particular functional failure.

Scored Bearing

Worn Impeller

Bent Linkage




When possible list failure cause or When possible list failure cause or mechanism, ex. “cracked spar due to mechanism, ex. “cracked spar due to fatigue”fatigue”

List all failure modes that are “reasonable”. List all failure modes that are “reasonable”.

Be as descriptive as possibleBe as descriptive as possible

Do not combine failure modes where failure Do not combine failure modes where failure effects, rates, or possible failure effects, rates, or possible failure management solutions may be differentmanagement solutions may be different

Methods to identify “significant” failures Methods to identify “significant” failures vary by project. vary by project.

FMECAFMECAFMECAFMECAIdentifying Failure Modes:Identifying Failure Modes:Identifying Failure Modes:Identifying Failure Modes:



Failure mode sources:Failure mode sources:

Existing PM Tasks Existing PM Tasks Operating/Maintenance ManualsOperating/Maintenance Manuals Operator/Maintainer InputOperator/Maintainer Input Prior FMECA, RCM or other analysesPrior FMECA, RCM or other analyses Failure Databases (Age Exploration)Failure Databases (Age Exploration) Engineer/SME inputEngineer/SME input 3M/CMMS data***3M/CMMS data***




Common Errors:Common Errors:

Over dependence on CMMS or other “non-Over dependence on CMMS or other “non-specific” failure dataspecific” failure data

Lack of specificity in the failure mechanism, Lack of specificity in the failure mechanism, (“broken”) or of the failed part/location(“broken”) or of the failed part/location

Worrying about identifying all failures vice Worrying about identifying all failures vice the “important ones”the “important ones”

Confusing potential failures (e.g. “cracks”), Confusing potential failures (e.g. “cracks”), induced damage, or secondary damage from induced damage, or secondary damage from failure causesfailure causes

Failure to apply common sense or Failure to apply common sense or analyst/SME knowledge to data analyst/SME knowledge to data





SYSTEMSYSTEM1A1A

SYSTEMSYSTEM1C1C

GEAR BOXGEAR BOX1B3B1B3B

SUBSYSTEMSUBSYSTEM 1B21B2

SUBSYSTEMSUBSYSTEM1B41B4

SUBSYSTEMSUBSYSTEM1B11B1

MOTORMOTOR1B3A1B3A

PRESSUREPRESSUREREG 1B3EREG 1B3E SUB-ASSY

ITEMUNDER ANALYSIS

NEXT HIGHER

ENDITEM

HYDRAULICHYDRAULICSYSTEM 1BSYSTEM 1B

AIRCRAFTAIRCRAFT11

HYD PUMPHYD PUMP1B3D1B3D

CENT PUMPCENT PUMP1B3C1B3C

Impeller wornImpeller worn(FM)(FM)


FAILURE EFFECTFAILURE EFFECTThe result of a failure mode and it’s functional The result of a failure mode and it’s functional failure on surrounding items, the functional failure on surrounding items, the functional capability of the end item, and hazards to personnel capability of the end item, and hazards to personnel and environment.and environment.

HYD PUMPHYD PUMPASSY 1B3ASSY 1B3



When listing effects:When listing effects: List most severe effectsList most severe effects Should be reasonableShould be reasonable

Qualify less likely effects with terms such Qualify less likely effects with terms such as “possible” or “potential”as “possible” or “potential”

Include restorative actions, as appropriateInclude restorative actions, as appropriate Consider compensating provisions Effects should be identified at point of

functional failure

FMECAFMECAFMECAFMECAIdentifying Failure Effects:Identifying Failure Effects:Identifying Failure Effects:Identifying Failure Effects:




When properly identified:When properly identified: Makes the rest of the analysis much Makes the rest of the analysis much

easier easier Effects must address functional failure Effects must address functional failure

but should also consider secondary but should also consider secondary damagedamage

Hidden failures must assume the Hidden failures must assume the condition that makes them evident condition that makes them evident has occurredhas occurred

Effects must be clearly related to operational scenarios



Pay attention to level of effects: Pay attention to level of effects:

Local: effect on the failed part: “Loss Local: effect on the failed part: “Loss of Impeller effectiveness.” of Impeller effectiveness.”

Next higher: effect on the function of Next higher: effect on the function of the system/subsystem being analyzed, the system/subsystem being analyzed, often synonymous with functional often synonymous with functional failure: “Loss of Hydraulic Sys #1 failure: “Loss of Hydraulic Sys #1 pressure.”pressure.”

End: what the failure means to the End: what the failure means to the asset: “Loss of mission.”asset: “Loss of mission.”




Sources: Sources:

• Operating ManualsOperating Manuals• Maintenance Manuals Maintenance Manuals • Operator/maintainer/engineer inputOperator/maintainer/engineer input• Troubleshooting chartsTroubleshooting charts• SME/Analyst knowledgeSME/Analyst knowledge• Accident/Incident/Hazard reportsAccident/Incident/Hazard reports• Failure/Engineering InvestigationsFailure/Engineering Investigations• Test reportsTest reports

FMECAFMECAFMECAFMECAFailure Effects Sources:Failure Effects Sources:Failure Effects Sources:Failure Effects Sources:



FMECAFMECAFMECAFMECAFailure Effects ErrorsFailure Effects ErrorsFailure Effects ErrorsFailure Effects Errors

Common errors:Common errors:

• Assuming PM in placeAssuming PM in place• Incorrect levels Incorrect levels • Ignoring secondary damage Ignoring secondary damage • Improper treatment of hidden failuresImproper treatment of hidden failures



Identifying FMECA Terms:Identifying FMECA Terms:Identifying FMECA Terms:Identifying FMECA Terms: FMECAFMECAFMECAFMECA

Class ExerciseClass ExerciseObjective:Objective:

Identify and list the Coffee Maker’s Identify and list the Coffee Maker’s

• Failure ModesFailure Modes

• Failure EffectsFailure Effects

Extra CreditExtra Credit

• Describe how operating context Describe how operating context impacts failure effects impacts failure effects (Residential vs Commercial Use)(Residential vs Commercial Use)

Failure Modes/Effects next ...



FUNCTION 1FUNCTION 1- Brew 1 to 12 cups of coffee- Brew 1 to 12 cups of coffee

FUNCTIONAL FAILURE AFUNCTIONAL FAILURE A – Fails to brew coffee – Fails to brew coffee

FAILURE MODE 1FAILURE MODE 1 - Clogged heating chamber tubing - Clogged heating chamber tubing due to excessive calcium build-up.due to excessive calcium build-up.

FAILURE EFFECTFAILURE EFFECT - No coffee - No coffee

FAILURE MODE 2FAILURE MODE 2 - Shorted wiring due to frayed - Shorted wiring due to frayed insulation.insulation.

FAILURE EFFECTFAILURE EFFECT - Possible fire - Possible fire

FAILURE MODE 3FAILURE MODE 3 - Open On/Off switch due to - Open On/Off switch due to corrosion.corrosion.

FAILURE EFFECTFAILURE EFFECT - No coffee - No coffee

Coffee MakerCoffee MakerFailure Modes and Failure Modes and

EffectsEffects



FUNCTION 2FUNCTION 2 - Maintain coffee temperature at 120°f - Maintain coffee temperature at 120°f 5°f. 5°f.

FUNCTIONAL FAILURE AFUNCTIONAL FAILURE A - Fails to heat coffee (< 100°f) - Fails to heat coffee (< 100°f)

FAILURE MODE 1FAILURE MODE 1 – Broken power supply wire to heating – Broken power supply wire to heating element connection.element connection.

FAILURE EFFECTFAILURE EFFECT - Cold coffee - Cold coffee

FAILURE MODE 2FAILURE MODE 2 – Heating plate thermostat internal – Heating plate thermostat internal failure.failure.

FAILURE EFFECTFAILURE EFFECT - Cold coffee- Cold coffee

FUNCTIONAL FAILURE BFUNCTIONAL FAILURE B - Heats coffee to hot (>125° f)- Heats coffee to hot (>125° f) FAILURE MODE 1FAILURE MODE 1 – Corroded heating plate thermostat. – Corroded heating plate thermostat.

FAILURE EFFECTFAILURE EFFECT - Possible damage to coffee maker. - Possible damage to coffee maker. Possible fire. Possible fire.


EffectsEffects



FUNCTION 2FUNCTION 2 - Maintain coffee at 120°f - Maintain coffee at 120°f 5°f. (continued) 5°f. (continued)

FUNCTIONAL FAILURE CFUNCTIONAL FAILURE C - Partially warm coffee (>100°f but < than - Partially warm coffee (>100°f but < than 115°f)115°f)

FAILURE MODE 1FAILURE MODE 1 - Corroded heating plate thermostat. - Corroded heating plate thermostat.

FAILURE EFFECTFAILURE EFFECT – Lukewarm coffee– Lukewarm coffee


EffectsEffects



FUNCTION 3 FUNCTION 3 - Automatically brew coffee within 15 minutes - Automatically brew coffee within 15 minutes of time specified by userof time specified by user

FUNCTIONAL FAILURE AFUNCTIONAL FAILURE A - Does not brew coffee at all - Does not brew coffee at all

FAILURE MODE 1FAILURE MODE 1 - Inoperative Clock due to internal - Inoperative Clock due to internal failurefailure

FAILURE EFFECTFAILURE EFFECT - No coffee- No coffee

FUNCTIONAL FAILURE BFUNCTIONAL FAILURE B - Brews coffee more than 15 - Brews coffee more than 15 minutes earlier than specifiedminutes earlier than specified

FAILURE MODE 1FAILURE MODE 1 - Clock operation too fast due to - Clock operation too fast due to internal failureinternal failure

FAILURE EFFECTFAILURE EFFECT - Old, bitter coffee- Old, bitter coffee

Coffee Maker Failure Coffee Maker Failure Modes and EffectsModes and Effects



FUNCTION 3 FUNCTION 3 - Automatically brew coffee within 15 minutes - Automatically brew coffee within 15 minutes of time specified by userof time specified by user

FUNCTIONAL FAILURE CFUNCTIONAL FAILURE C - Brews coffee more than 15 - Brews coffee more than 15 minutes after time specified by userminutes after time specified by user

FAILURE MODE 1FAILURE MODE 1 - Slow clock operation due to - Slow clock operation due to internal failureinternal failure

FAILURE EFFECTFAILURE EFFECT - No coffee until more than 15 - No coffee until more than 15 minutes after time specifiedminutes after time specified

Coffee Maker Failure Coffee Maker Failure Modes and EffectsModes and Effects



A note on “human error” failure modes:A note on “human error” failure modes:RCM may be used to address human error… RCM may be used to address human error…

Example: “Operator forgot to add water to Example: “Operator forgot to add water to coffee pot” coffee pot”

Solution: “Post checklist by coffee pot”Solution: “Post checklist by coffee pot”

However… Care should be taken not to However… Care should be taken not to overcompensate for human error where overcompensate for human error where other processes (human factors other processes (human factors engineering) or common sense should engineering) or common sense should presidepreside





FAILURE DETECTIONFAILURE DETECTIONDescribes method(s) by which functional Describes method(s) by which functional failures are detected and failure modes are failures are detected and failure modes are identified.identified.

Failure DetectionFailure Detection• Visual alarmsVisual alarms• Audible alarmsAudible alarms• Gauges/IndicatorsGauges/Indicators• Operating Operating characteristicscharacteristics

Identifying Failure ModesIdentifying Failure Modes• Voltage checksVoltage checks• Continuity checksContinuity checks• Visual inspectionsVisual inspections• PHM systemsPHM systems




FMECAFMECAFMECAFMECAFailure DetectionFailure DetectionFailure DetectionFailure Detection

Address both operator and maintainerAddress both operator and maintainer

• For operator: detection of FUNCTIONAL For operator: detection of FUNCTIONAL FAILURE (or effects)FAILURE (or effects)

• For maintainer: detection of FAILURE For maintainer: detection of FAILURE MODEMODE



FMECAFMECAFMECAFMECAFailure DetectionFailure DetectionFailure DetectionFailure Detection

Sources: Sources: Operator/maintainer interviewsOperator/maintainer interviews Maintenance/Operator’s ManualsMaintenance/Operator’s Manuals Troubleshooting chartsTroubleshooting charts Accident/Incident/Hazard reportsAccident/Incident/Hazard reports Failure/Engineering Failure/Engineering

InvestigationsInvestigations Test reportsTest reportsCommon Errors: Common Errors: Not addressing both operator and Not addressing both operator and

maintainermaintainer Listing specific PMListing specific PM




SEVERITY CLASSIFICATIONSEVERITY CLASSIFICATIONA category assigned to a failure mode based on A category assigned to a failure mode based on the impacts if its potential effects.the impacts if its potential effects.

Categories are defined by the organization Categories are defined by the organization performing the analysisperforming the analysis

Categories for the same failure mode may be Categories for the same failure mode may be different in different operating phases or different in different operating phases or scenariosscenarios




SEVERITY CATEGORYSEVERITY CATEGORY

Category ICategory I CatastrophicCatastrophicCategory ICategory I CatastrophicCatastrophic

• Aircraft example: “Death, Permanent Disability, Aircraft example: “Death, Permanent Disability, destruction of equipment/system, damage in destruction of equipment/system, damage in excess of $1M, significant breach of environmental excess of $1M, significant breach of environmental regulation.regulation.

• Critical equipment example: “Death, Permanent Critical equipment example: “Death, Permanent Disability, destruction of equipment/system,Disability, destruction of equipment/system, damage in excess of $1M, significant breach of damage in excess of $1M, significant breach of environmental regulation, Down-time > 2 daysenvironmental regulation, Down-time > 2 days

FMECA Terms:FMECA Terms:FMECA Terms:FMECA Terms: FMECAFMECAFMECAFMECA





Category IICategory II CriticalCriticalCategory IICategory II CriticalCritical• Aircraft example: “Personal Injury, Damage Aircraft example: “Personal Injury, Damage more than $100K but less than $1M, Inability to more than $100K but less than $1M, Inability to perform a critical mission”perform a critical mission”

• Critical equipment example: “Personal Critical equipment example: “Personal Injury, Damage more than $100K but less than Injury, Damage more than $100K but less than $1M, Down-time more than 24 hours but less $1M, Down-time more than 24 hours but less than two days”than two days”




• Aircraft example: “Damage more than $1K Aircraft example: “Damage more than $1K but less than $100K, Degraded ability to but less than $100K, Degraded ability to perform a critical mission”perform a critical mission”

• Critical Equipment example: “Damage Critical Equipment example: “Damage more than $1K but less than $100K, Down-more than $1K but less than $100K, Down-time more than 8 hours but less than 24 time more than 8 hours but less than 24 hours”hours”



Category IICategory II CriticalCriticalCategory IICategory II CriticalCritical

Category IIICategory III MarginalMarginalCategory IIICategory III MarginalMarginal





• Aircraft example: “Damage less than $1K, Aircraft example: “Damage less than $1K, Unscheduled Maintenance or Repair”Unscheduled Maintenance or Repair”

• Equipment example: “Damage less than $1K, Equipment example: “Damage less than $1K, Down-time less than 8 hours”Down-time less than 8 hours”


Category IICategory II CriticalCriticalCategory IICategory II CriticalCritical

Category III Category III MarginalMarginalCategory III Category III MarginalMarginal

Category IV Category IV MinorMinorCategory IV Category IV MinorMinor





MEAN TIME BETWEEN FAILURE (MTBFMEAN TIME BETWEEN FAILURE (MTBF)Basic measure of reliability for an item.Basic measure of reliability for an item.

• Average time between failure occurrences Average time between failure occurrences during a specified period with no during a specified period with no preventive measures in placepreventive measures in place• Usually: Total operating time in given period Usually: Total operating time in given period

divided by number of failures that have divided by number of failures that have occurredoccurred

• Inverse of the failure rateInverse of the failure rate• Adjustment required if PM is already in-placeAdjustment required if PM is already in-place

Used in RCM for prioritizing failure modes, Used in RCM for prioritizing failure modes, performing cost analysis and Failure Finding performing cost analysis and Failure Finding Task Interval Calculations Task Interval Calculations




CALCULATING MTBF (Method 1)CALCULATING MTBF (Method 1)

Total operating time/number of failures Total operating time/number of failures (mature populations in a specified time (mature populations in a specified time period)period)

When no failures have occurred use a When no failures have occurred use a conservative estimateconservative estimate

Evaluate like and similar equipmentEvaluate like and similar equipment Consider possibility of failure in short Consider possibility of failure in short period of timeperiod of time

Calculating MTBF:Calculating MTBF:Calculating MTBF:Calculating MTBF: FMECAFMECAFMECAFMECA




Sources:Sources:

•CMMS dataCMMS data

•Third party repair recordsThird party repair records

•Supply usage data Supply usage data

•Artisan/Maintainer anecdotal Artisan/Maintainer anecdotal

estimatesestimates



Method 1 Cautions:Method 1 Cautions: Need data specific to item Need data specific to item Understand difference between potential Understand difference between potential

failures and functional failuresfailures and functional failures

Note: MTBF based on potential failures may Note: MTBF based on potential failures may need adjustmentneed adjustment

Adjustments may be required to establish Adjustments may be required to establish MTBF where PM is already in placeMTBF where PM is already in place

Make sure time period chosen is Make sure time period chosen is representative (steady-state)representative (steady-state)

Assumes constant failure rate of the Assumes constant failure rate of the populationpopulation

May require periodic monitoring/updateMay require periodic monitoring/update





Use Design or predicted valuesUse Design or predicted values

•Data sources:Data sources:•Design/vendor specs Design/vendor specs •““Like and similar” equipmentLike and similar” equipment•Analytical/handbook predictionsAnalytical/handbook predictions

•Caution: Often inaccurate Caution: Often inaccurate • Verify with real data if possibleVerify with real data if possible• Adjust with conservatism where Adjust with conservatism where

necessarynecessary• Monitor/Update when field data Monitor/Update when field data

becomes availablebecomes available





Statistical Modeling methodsStatistical Modeling methods

•Beyond scope of this courseBeyond scope of this course• Requires specialized training and Requires specialized training and

knowledgeknowledge•May be most accurate if properly May be most accurate if properly

performedperformed




CriticalityCriticalityCriticalityCriticality FMECAFMECAFMECAFMECA• Combination of Severity and Frequency (MTBF)Combination of Severity and Frequency (MTBF)

• Hazard Risk Index (HRI)Hazard Risk Index (HRI)• Risk Priority Number (RPN)Risk Priority Number (RPN)



FREQUENCYFREQUENCY

SEVERITYSEVERITY

FREQUENTFREQUENT (A)(A)

>> 1 per 1,000 1 per 1,000 HoursHours

PROBABLEPROBABLE (B) (B)

>> 1 per 10,000 1 per 10,000HoursHours

OCCASIONALOCCASIONAL (C) (C)

>> 1 per 100,000 1 per 100,000HoursHours

REMOTE REMOTE (D)(D)

>> 1 per 1,000,000 1 per 1,000,000HoursHours

IMPROBABLEIMPROBABLE (E) (E)

<< 1 per 1,000,000 1 per 1,000,000HoursHours

CATASTROPHIC (I)CATASTROPHIC (I)

CRITICAL (II)CRITICAL (II)

MARGINAL (III)MARGINAL (III)

MINOR (IV)MINOR (IV)

• Death or Permanent disabilityDeath or Permanent disability• Significant Environmental breach Significant Environmental breach • Damage > $1M, Downtime>2 daysDamage > $1M, Downtime>2 days• Destruction of system/equipmentDestruction of system/equipment

• Personal InjuryPersonal Injury• Damage >$100K and < $1MDamage >$100K and < $1M• Loss of availability > 24 hrs and Loss of availability > 24 hrs and < 7 days< 7 days

• Damage >$10K and < $100KDamage >$10K and < $100K• Loss of availability > 4 hrs andLoss of availability > 4 hrs and < 24 hrs< 24 hrs

• Damage <$10K Damage <$10K • Loss of availability < 4 hrsLoss of availability < 4 hrs

11HIGHHIGH

33HIGHHIGH

44HIGHHIGH

22HIGHHIGH

55HIGHHIGH

88MEDMED

66MEDMED

77MEDMED

99MEDMED

1010LOWLOW

1212ACCEPTACCEPT

1313ACCEPTACCEPT

1515ACCEPTACCEPT

1616ACCEPTACCEPT

1717ACCEPTACCEPT

2020ACCEPT

1919ACCEPT

1414ACCEPT

1111LOWLOW

1818ACCEPTACCEPT

• Item – What it isItem – What it is• Functions – What you want item to doFunctions – What you want item to do• Functional Failures – How it fails to do it Functional Failures – How it fails to do it • Failure Modes – Why it fails to do itFailure Modes – Why it fails to do it• Failure Effects – What happensFailure Effects – What happens• Severity of Failure – How bad it isSeverity of Failure – How bad it is• Failure Frequency – How often it Failure Frequency – How often it

happenshappens• Criticality – Severity + Frequency Criticality – Severity + Frequency

• Item – What it isItem – What it is• Functions – What you want item to doFunctions – What you want item to do• Functional Failures – How it fails to do it Functional Failures – How it fails to do it • Failure Modes – Why it fails to do itFailure Modes – Why it fails to do it• Failure Effects – What happensFailure Effects – What happens• Severity of Failure – How bad it isSeverity of Failure – How bad it is• Failure Frequency – How often it Failure Frequency – How often it

happenshappens• Criticality – Severity + Frequency Criticality – Severity + Frequency

FMECA Summary:FMECA Summary:FMECA Summary:FMECA Summary: FMECAFMECAFMECAFMECA



Guidance:Guidance:Guidance:Guidance: ReferencesReferencesReferencesReferences

• NAVAIR 00-25-403: Guidelines for the Naval Aviation RCM NAVAIR 00-25-403: Guidelines for the Naval Aviation RCM processprocess

• SAE JA1012: Society of Automotive Engineers Guide to RCM SAE JA1012: Society of Automotive Engineers Guide to RCM StandardStandard

• RAC-HDBK-1120: FMECA - Failure Mode, Effects and RAC-HDBK-1120: FMECA - Failure Mode, Effects and Criticality AnalysisCriticality Analysis

• MIL-STD-1629A: MIL-STD-1629A: Procedures for Performing a Failure Mode, Procedures for Performing a Failure Mode, Effects, and Criticality AnalysisEffects, and Criticality Analysis

• MIL-HDBK-217: Reliability Prediction of Electronic MIL-HDBK-217: Reliability Prediction of Electronic Equipment.Equipment.

• MIL-STD-882D: Standard Practice For System SafetyMIL-STD-882D: Standard Practice For System Safety

• NAVAIRINST 5100.11: Research and Engineering Review of NAVAIRINST 5100.11: Research and Engineering Review of Risk Process and Procedures for Processing Grounding Risk Process and Procedures for Processing Grounding BulletinsBulletins



Sources:Sources:Sources:Sources: ReferencesReferencesReferencesReferences

Useful Data Sources For Identifying FMECA Useful Data Sources For Identifying FMECA Information are:Information are:• Maintenance/Operators ManualsMaintenance/Operators Manuals• Troubleshooting Guides/ChartsTroubleshooting Guides/Charts• DrawingsDrawings• Operators/Maintainers/Engineers/OEM Tech Operators/Maintainers/Engineers/OEM Tech RepsReps• Work Orders/CMMS or other failure data Work Orders/CMMS or other failure data • Block Diagrams/SchematicsBlock Diagrams/Schematics• Existing PM TasksExisting PM Tasks• Accident/Incident/Hazard reportsAccident/Incident/Hazard reports• Engineering/Failure Investigations/Test reportsEngineering/Failure Investigations/Test reports



Review and Review and summarysummary

Review and Review and summarysummary

Provided an understanding of the Failure Provided an understanding of the Failure Modes, Effects, and Criticality Analysis Modes, Effects, and Criticality Analysis (FMECA).(FMECA).IntroductionIntroductionIntroductionIntroduction

Learning ObjectivesLearning Objectives


• Definition of a FMEADefinition of a FMEA• Purpose of a FMECAPurpose of a FMECA• Definitions & Identification ProcessDefinitions & Identification Process

ReferencesReferencesReferencesReferences



Module ObjectiveModule ObjectiveModule ObjectiveModule Objective

End of Module up next……..

RCM Decision Logic

End of Module up next……..

RCM Decision Logic

rcm fmeca.ppt

Documents

rcm analysis

analysis items

criticality analysis

concept of failure mode

itemdescribe functions

possiblestate functions

failure mtbf3

associated effects