ON CONDITION TASK Module 3 UNIT III HOW TO PERFORM RCM " Copyright 2002, Information Spectrum, Inc. All Rights Reserved."

ON CONDITION TASKON CONDITION TASKON CONDITION TASKON CONDITION TASK

Module 3Module 3

UNIT IIIUNIT III

HOW TO PERFORM RCMHOW TO PERFORM RCMHOW TO PERFORM RCMHOW TO PERFORM RCM

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

Module Preview:Module Preview:Module Preview:Module Preview: IntroductioIntroductionn

IntroductioIntroductionn

• IntroductionIntroduction• IntroductionIntroduction

• Task DevelopmentTask Development • Task DevelopmentTask Development

• Review and summaryReview and summary• Review and summaryReview and summary



Module Objective:Module Objective:

This module will provide information for This module will provide information for developingdeveloping andand evaluating On Condition evaluating On Condition

tasks:tasks:

1. Identify when it is appropriate to develop an On 1. Identify when it is appropriate to develop an On Condition taskCondition task

2. Show how to develop an On Condition task for a 2. Show how to develop an On Condition task for a given failure modegiven failure mode

3. Show how to determine an appropriate task 3. Show how to determine an appropriate task interval for an On Condition taskinterval for an On Condition task

IntroductioIntroductionn

ON CONDITIONON CONDITIONTASK DEVELOPMENTTASK DEVELOPMENT

ON CONDITIONON CONDITIONTASK DEVELOPMENTTASK DEVELOPMENT


On Condition Task:On Condition Task: Task DevelopmentTask Development

Definition -Definition - A periodic or continuous A periodic or continuous inspection designed to detect a potential inspection designed to detect a potential failure condition prior to functional failurefailure condition prior to functional failure

• If the inspection reveals a potential If the inspection reveals a potential failure condition, corrective action must failure condition, corrective action must be takenbe taken

• If potential failure condition does not If potential failure condition does not exist, nothing is done, item continues in exist, nothing is done, item continues in serviceservice


On Condition Task:On Condition Task:

• On-condition task objective is to maximize On-condition task objective is to maximize the useful life of each piece of equipment the useful life of each piece of equipment by allowing operation until a potential by allowing operation until a potential failure is detected failure is detected

• Task includes only inspection portion of Task includes only inspection portion of the maintenance actionthe maintenance action

• Can be accomplished with Condition Can be accomplished with Condition Monitoring/PdM/PHM systemsMonitoring/PdM/PHM systems

Task DevelopmentTask Development


Questions:Questions:

• What is the What is the Functional FailureFunctional Failure??

• What is theWhat is the Potential FailurePotential Failure??

• What is the What is the Potential Failure to Functional Potential Failure to Functional Failure (PF) intervalFailure (PF) interval and how consistent is and how consistent is it?it?

• Can a task be developed that provides Can a task be developed that provides an an acceptable probability of detecting the acceptable probability of detecting the potential failure prior to functional failurepotential failure prior to functional failure??

• Is the Is the tasktask and and required intervalrequired interval practical? practical?



Functional Failure:Functional Failure:

• Inability of item to perform a specific Inability of item to perform a specific function within specified performance limitsfunction within specified performance limits

• Functional Failure is identified and Functional Failure is identified and documented during FMECAdocumented during FMECA

• FF condition may be redefined for purposes of OC FF condition may be redefined for purposes of OC tasktask

• If function ceases, Functional Failure has occurredIf function ceases, Functional Failure has occurred

• May also be defined as prior to complete loss of May also be defined as prior to complete loss of functionfunction

• Must be known before valid Potential Must be known before valid Potential Failure-to-Functional Failure interval can be Failure-to-Functional Failure interval can be establishedestablished



OPERATING AGEOPERATING AGE

AA

FUNCTIONALFUNCTIONALFAILUREFAILURE

POTENTIALPOTENTIALFAILUREFAILURE

BB

CC

DEFINED POTENTIAL DEFINED POTENTIAL FAILURE CONDITIONFAILURE CONDITION


Inspection IntervalInspection Interval

Functional Failure:Functional Failure:

TASK INTERVAL PRACTICAL?PRACTICAL?TASK INTERVAL PRACTICAL?PRACTICAL?

I I I


PF IntervalPF IntervalPF IntervalPF Interval


DEFINED FUNCTIONALDEFINED FUNCTIONALFAILURE CONDITION FAILURE CONDITION

Functional Capability

Potential Failure:Potential Failure:

• DefinableDefinable and detectable condition that and detectable condition that indicates a functional failure will occurindicates a functional failure will occur

• Potential failure is a definable and Potential failure is a definable and detectable degradation characteristic detectable degradation characteristic

• Defining Potential Failure:Defining Potential Failure:

• at earliest detectable condition will at earliest detectable condition will lengthen the On Condition task intervallengthen the On Condition task interval

• closer to functional failure will allow closer to functional failure will allow greater usage of available life of itemgreater usage of available life of item




AA



BB

CC




FUNCTIONAL FUNCTIONAL CAPABILITYCAPABILITY

Potential Failure:Potential Failure:

TASK INTERVALTASK INTERVAL PRACTICALPRACTICAL?TASK INTERVALTASK INTERVAL PRACTICALPRACTICAL?

I I I


PF IntervalPF IntervalPF IntervalPF Interval



PF Interval:PF Interval:

PF Interval:PF Interval: The time in some traceable The time in some traceable operating unit between occurrence of operating unit between occurrence of potential and functional failurepotential and functional failure

Safety consequences:Safety consequences:

• PF interval may need to be PF interval may need to be determined analyticallydetermined analytically or through or through laboratory testinglaboratory testing

• Method used depends on the failure modeMethod used depends on the failure mode

• Age Exploration may be necessary to Age Exploration may be necessary to collect datacollect data



PF Interval:PF Interval: Task DevelopmentTask Development

Non-Safety consequences:Non-Safety consequences:

• Gather data from experience/CMMS Gather data from experience/CMMS datadata

• Age Exploration on in-service Age Exploration on in-service equipmentequipment

• Method used depends on the failure Method used depends on the failure modemode



A



BB

CC




PF Interval:PF Interval:

TASK INTERVALTASK INTERVAL PRACTICALPRACTICAL?TASK INTERVALTASK INTERVAL PRACTICALPRACTICAL?

I I I




PF IntervalPF Interval


• Task interval determined from PF intervalTask interval determined from PF interval

• Usually, inspection must occur at least Usually, inspection must occur at least once during PF intervalonce during PF interval

• More inspections during the PF interval More inspections during the PF interval may be required to ensure acceptable may be required to ensure acceptable levels of safety, mission, and economics levels of safety, mission, and economics are achievedare achieved

Task DevelopmentTask DevelopmentDetermining Task Interval:Determining Task Interval:



AA



BB

CC

DEFINED POTENTIAL FAILURE CONDITION

DEFINED POTENTIAL FAILURE CONDITION

Task Interval :Task Interval :

TASK INTERVALTASK INTERVALTASK INTERVALTASK INTERVALI I I




PF IntervalPF Interval


Task DevelopmentTask DevelopmentDetermining Task Interval:Determining Task Interval:


Inspection Interval (I): (Ref: NAVAIR 00-25-Inspection Interval (I): (Ref: NAVAIR 00-25-403)403)

I = PF/nI = PF/nwhere: where: PF PF = interval from potential failure to functional = interval from potential failure to functional failurefailuren n = number of inspections during PF interval= number of inspections during PF interval

Example:Example:

Determining On Condition Inspection Interval for Tail HookDetermining On Condition Inspection Interval for Tail Hook

CRACKCRACKLIMITSLIMITS

1/641/64

3/643/64

0

FUNCTIONAL FAILUREFUNCTIONAL FAILURE

POTENTIAL FAILUREPOTENTIAL FAILURE

75050 150 250 350 450 550 650 850100 200 300 400 500 600 700 800

ARRESTMENTS



Example:Example:

680600 620 640 660 700610 630 650 670 690

ARRESTMENTS

10 1010

SampleA

SampleB

Determining On Condition Inspection Interval for Determining On Condition Inspection Interval for Tail HookTail Hook

710 720 730590580570560

Inspection Interval = 10 Arrests



10 101010

Determining Task Interval:Determining Task Interval: Task DevelopmentTask Development

Failure modes with Safety Consequences:Failure modes with Safety Consequences:

• Goal is to develop task interval that will Goal is to develop task interval that will reduce the probability of experiencing a reduce the probability of experiencing a failure to an acceptable levelfailure to an acceptable level

Failure Modes with Non Safety Consequences:Failure Modes with Non Safety Consequences:

• Goal is to determine task interval that Goal is to determine task interval that yields the most cost effective task yields the most cost effective task realizing some functional failures may be realizing some functional failures may be OK if overall cost is minimized.OK if overall cost is minimized.


• Engineering judgment using maintenance Engineering judgment using maintenance data, engineering/technical information, SME data, engineering/technical information, SME input, etc.input, etc.

• If PF is unknown but failure mode clearly has If PF is unknown but failure mode clearly has a progressive failure mechanism, work a progressive failure mechanism, work backwards from an existing effective task to backwards from an existing effective task to determine a PF intervaldetermine a PF interval

• If current task is less effective than If current task is less effective than desired, adjust PF as a function of current desired, adjust PF as a function of current task effectiveness to get new PF task effectiveness to get new PF

• Analytical methods provided in NA 00-25-Analytical methods provided in NA 00-25-403403

Task DevelopmentTask DevelopmentEstimating Methods:Estimating Methods:




Determining whether any particular analytical Determining whether any particular analytical method is appropriate is the responsibility of method is appropriate is the responsibility of the analystthe analyst

Common Errors:Common Errors:

• Getting bogged down by lack of data Getting bogged down by lack of data (use best judgment) (use best judgment)

• Using existing task interval instead of Using existing task interval instead of analyst judgment when NOT appropriate analyst judgment when NOT appropriate

• Lack of documentation of decisions in Lack of documentation of decisions in memo fieldmemo field

• Excessive conservatismExcessive conservatism

• Using MTBFUsing MTBF



Additional Considerations:Additional Considerations:

• Ensure repair actions do not reduce the PF Ensure repair actions do not reduce the PF interval, otherwise a new PF interval may interval, otherwise a new PF interval may be required for repaired itemsbe required for repaired items

• Explore various inspection techniques Explore various inspection techniques

• Ensure PF is adjusted for the inspection Ensure PF is adjusted for the inspection techniquetechnique

• Ensure published repair limits are Ensure published repair limits are consistent with Potential Failures identified consistent with Potential Failures identified by OC tasksby OC tasks

Review and Review and SummarySummary

IntroductionIntroduction– Learning ObjectiveLearning Objective

Task Task DevelopmentDevelopment – Questions to be addressedQuestions to be addressed

– Identifying Failure Resistance IndicatorIdentifying Failure Resistance Indicator– Identifying Functional Failure ConditionIdentifying Functional Failure Condition– Identifying Potential Failure ConditionIdentifying Potential Failure Condition– Determining PF IntervalDetermining PF Interval– Determining Task IntervalDetermining Task Interval

– Default MethodsDefault Methods


Module ObjectiveModule Objective

– Provide detailed information for evaluating and Provide detailed information for evaluating and developing an On Condition task.developing an On Condition task.

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ON CONDITION TASK Module 3 UNIT III HOW TO PERFORM RCM " Copyright 2002, Information Spectrum, Inc. All Rights Reserved."