Conference AERONET Aviation Valley 13 14 2011 Risk

Conference AERONET "Aviation Valley" , 13 -14 2011 Risk assessment in aerospace systems Jacek S. Stecki PHM Technology/Monash University Melbourne, Australia Jacek S. Stecki PHM Technology Pty Ltd 1

Conference AERONET "Aviation Valley" , 13 -14 2011 Key issues – Risk drivers Supportability: – Reduction of life-cycle cost – Safety – environmental, personnel – Reliability – hardware, functional Reduced manning levels Need to reduce the volume of scheduled maintenance Secondary effects of failures Inherent design problems Need to reduce spare parts inventory High performance requirements Availability of specialised personnel Insurance and classification Criticality of the equipment to productivity/availability Cost of lost production or lost availability as a result of equipment failure Cost of fixing a problem in terms of repair and bringing the machine back to a serviceable condition Etc. Jacek S. Stecki PHM Technology Pty Ltd 2

Conference AERONET "Aviation Valley" , 13 -14 2011 Integrated Logistics Support Integrated logistics support (ILS) is an integrated approach to the management of logistic disciplines in the military The pupose of ILS is to ensure that the supportability of the system is considered during its design and development in order: To create systems that last longer and require less support To reduce costs To increase return on investments To assure supportability throught the operational life of the system The impact of ILS is measured in metrics: Reliability - Availability - Maintainability (RAM) Reliability - Availability - Maintainability - Testability (RAMT) Reliability - Availability - Maintainability - System safety (RAMS). Jacek S. Stecki PHM Technology Pty Ltd 3

Conference AERONET "Aviation Valley" , 13 -14 2011 Integrated Logistics Support Assuring continued operation and functioning of the systems Jacek S. Stecki PHM Technology Pty Ltd 4

Conference AERONET "Aviation Valley" , 13 -14 2011 Performance-based Logistics (PBL) is an outcome-based, performanceoriented product support strategy A product support provider (PSP) or product support integrator (PSI) is contracted to meet performance metric (s) for a system or product The purpose of PBL: increased system availability, reliability shorter maintenance cycles, and/or reduced costs Thus PBL fits well with ILS -----------------– – In U. S. Department of Defense (Do. D) acquisition programs, the PBL approach is mandated as a first -choice strategy. A PBL contract was awarded to Alstom for delivery of trains in France Also called Performance-based-Contracts Jacek S. Stecki PHM Technology Pty Ltd 5

Conference AERONET "Aviation Valley" , 13 -14 2011 Reliability - Availability – Maintainability (RAM) The ability of an item to perform a required function under given conditions for a given time interval It is generally assumed that the item is in a state to perform this required function at the beginning of the time interval Generally, reliability performance is quantified using appropriate measures. In some applications these measures include an expression of reliability performance as a probability, which is also called reliability. Jacek S. Stecki PHM Technology Pty Ltd 6

Conference AERONET "Aviation Valley" , 13 -14 2011 Risk reduction – CBM/PHM What is it? Risk assessment using techniques like FMECA, HAZOP, RCM etc. Diagnostics – is the process of determining the state of a component to perform its function(s) Prognostics – is predictive diagnostics which includes determining the remaining life or time span of properation of a component Health Management – is the capability to make appropriate decisions about maintenance actions based on diagnostics/prognostics information, available resources and operational demand. Jacek S. Stecki PHM Technology Pty Ltd 7

Conference AERONET "Aviation Valley" , 13 -14 2011 PHM - Fusion of the technologies Sensors Artificial intelligence Neural nets, fuzzy logic, genetic algorithms Algorithms (vibration etc. ) Communication capabilities Interchange of maintenance data Integration of data Security of data User friendly interface Autonomy to be provided by software agents (Jack platform from AOS) Jacek S. Stecki PHM Technology Pty Ltd 8

Conference AERONET "Aviation Valley" , 13 -14 2011 Goals of PHM Enhance Mission Reliability and Equipment Safety Reduce Maintenance Manpower, Spares, and Repair Costs Eliminate Scheduled Inspections Maximize Lead Time For Maintenance and Parts Procurement Automatically Isolate Faults Provide Real Time Notification of an Upcoming Maintenance Event at all Levels of the Logistics Chain Catch Potentially Catastrophic Failures Before They Occur Detect Incipient Faults and Monitor Until Just Prior to Failure Jacek S. Stecki PHM Technology Pty Ltd 9

Conference AERONET "Aviation Valley" , 13 -14 2011 PHM Paradigm (Joint Strike Fighter F 35) Jacek S. Stecki PHM Technology Pty Ltd 10

Conference AERONET "Aviation Valley" , 13 -14 2011 Joint Strike Fighter F 35 PHM Setup Jacek S. Stecki PHM Technology Pty Ltd 11

Conference AERONET "Aviation Valley" , 13 -14 2011 Aerospace Risks Severe operating environment Stringent statutory safety standards Safety critical systems Expensive Maintenance Long innovation lead time High technology Conservative attitudes High reliability requirements Single shot operations Very high cost of failure Tools to deal with risks Computer based design methods Reliability and Hazard Analysis Failure analysis (FMECA/FTA) PHM (Prognostics and Health Management) Condition Monitoring - CBM Testing Jacek S. Stecki PHM Technology Pty Ltd 12

Conference AERONET "Aviation Valley" , 13 -14 2011 go rit Failure modes sses Lo n o i t c u rod l na tio is nc lys Fu na A hm s CBM/PHM - what are we dealing with? n o Al FM i t Detection s a r P rognz Standards nso ostic e i BIT S Dia s gno m Training i sis Simulation ! n i $ Fault Tree e c Condition monitoring Sensor fusion n$ M a Do n $ e wn t in$ Fau k tim a M$ lts e s i s rd $ a z a R Safety H $ Testing Fall-back Analysis P R el ia bi lit y A EC Training Jacek S. Stecki PHM Technology Pty Ltd A in rtif te ic llig ia en l ce ai la bi lit y Education Av y ilit b na i ta n ai M ROI 13

Conference AERONET "Aviation Valley" , 13 -14 2011 Reasons for failure of Risk Assessment Dependencies of failures not identified – spreadsheet vs model based Inadequate Identification of Risks - functional failures (failure modes) vs physical failures Incomplete database of failures (deficient FMECA) Taxonomy – confusion what is the cause, mechanism of failure, fault, symptom and/or failure mode Sensor fusion not based on failures dependencies (fall-back – testability) Diagnostic rules not based on dependencies Reliability of Hardware not the same as Functional Reliability Different models for Criticality and Reliability Assessment Jacek S. Stecki PHM Technology Pty Ltd 14

Conference AERONET "Aviation Valley" , 13 -14 2011 Risk reduction or is it? Risk is still there if failures are missed We cannot design a diagnostic system without knowledge of failures We do not really know what we should monitor Sensors cover only identified failures Jacek S. Stecki PHM Technology Pty Ltd 15

Conference AERONET "Aviation Valley" , 13 -14 2011 Barriers The Advanced Technology Program (ATP), of the National Institute of Standards and Technology (NIST), held a workshop on Condition-Based Maintenance (CBM) as part of it's November 17 -18, 1998 Fall Meeting in Atlanta. Discussions with companies identified 3 technical barriers to CBM's widespread implementation: The inability to accurately and reliably predict the remaining useful life of a machine ( prognostics) The inability to continually monitor a machine (sensing) The inability of maintenance systems to learn and identify impending failures and recommend what action should be taken (reasoning). These barriers could potentially be addressed through innovations in three technical areas: Prognostication capabilities Cost effective sensor and monitoring systems Reasoning or expert systems Jacek S. Stecki PHM Technology Pty Ltd 16

Conference AERONET "Aviation Valley" , 13 -14 2011 Risk Assessment FMECA Failure Modes Possible Failures FMECA Effects What effect does the failure have ? FMECA Criticality Analysis FMECA of failure Jacek S. Stecki PHM Technology Pty Ltd 17

Conference AERONET "Aviation Valley" , 13 -14 2011 Modeling Failure Jacek S. Stecki PHM Technology Pty Ltd 18

Conference AERONET "Aviation Valley" , 13 -14 2011 Modelling of failure Jacek S. Stecki PHM Technology Pty Ltd 19

Conference AERONET "Aviation Valley" , 13 -14 2011 Fault propagation - dependability All faults are enumerated. Transient and steady-state responses to faults are identified Jacek S. Stecki PHM Technology Pty Ltd 20

Conference AERONET "Aviation Valley" , 13 -14 2011 PHM Cycle PHM requires two main cycles of development, design and operation The Design Cycle is required in order to generate the knowledge base from which the PHM system can obtain its decisions. The Operation Cycle describes the steps taken within the PHM system from detection of faults through to conveying instructions or actions. Jacek S. Stecki PHM Technology Pty Ltd 21

Conference AERONET "Aviation Valley" , 13 -14 2011 Interaction between MAD and CBM/PHM Layers at Design Stage MAD – Maintenance aware Design Jacek S. Stecki PHM Technology Pty Ltd 22

Conference AERONET "Aviation Valley" , 13 -14 2011 Criteria for RCM Processes SAE JA 1011 “Evaluation Criteria for RCM Processes” defines seven questions for RCM: What are the functions…of the asset…(functions)? In what ways can it fail…(functional failures)? What causes each functional failure (failure modes)? What happens when each failure occurs (failure effects)? In what way does each failure matter (failure consequences)? What should be done…(proactive tasks and intervals)? What should be done if a suitable proactive task cannot be found? Jacek S. Stecki PHM Technology Pty Ltd 23

Conference AERONET "Aviation Valley" , 13 -14 2011 MADe software Jacek S. Stecki PHM Technology Pty Ltd 24

Conference AERONET "Aviation Valley" , 13 -14 2011 RR 250 Engine Lubrication System Jacek S. Stecki PHM Technology Pty Ltd 25

Conference AERONET "Aviation Valley" , 13 -14 2011 Jet Engine Lubrication System Model Jacek S. Stecki PHM Technology Pty Ltd 26

Conference AERONET "Aviation Valley" , 13 -14 2011 Model of pump Jacek S. Stecki PHM Technology Pty Ltd 27

Conference AERONET "Aviation Valley" , 13 -14 2011 Define Component Structure Jacek S. Stecki PHM Technology Pty Ltd 28

Conference AERONET "Aviation Valley" , 13 -14 2011 Define Component Functions Jacek S. Stecki PHM Technology Pty Ltd 29

Conference AERONET "Aviation Valley" , 13 -14 2011 Define Physical Failures Jacek S. Stecki PHM Technology Pty Ltd 30

Conference AERONET "Aviation Valley" , 13 -14 2011 Propagate Functional Failures >> Dependency Jacek S. Stecki PHM Technology Pty Ltd 31

Conference AERONET "Aviation Valley" , 13 -14 2011 Assess Criticality Jacek S. Stecki PHM Technology Pty Ltd 32

Conference AERONET "Aviation Valley" , 13 -14 2011 Produce FMEA/FMECA Report Jacek S. Stecki PHM Technology Pty Ltd 33

Conference AERONET "Aviation Valley" , 13 -14 2011 Assess hardware Reliability Jacek S. Stecki PHM Technology Pty Ltd 34

Conference AERONET "Aviation Valley" , 13 -14 2011 Fault Tree Jacek S. Stecki PHM Technology Pty Ltd 35

Conference AERONET "Aviation Valley" , 13 -14 2011 Define Sensors Locations Jacek S. Stecki PHM Technology Pty Ltd 36

Conference AERONET "Aviation Valley" , 13 -14 2011 Select sensors and generate diagnostic rules Jacek S. Stecki PHM Technology Pty Ltd 37

Conference AERONET "Aviation Valley" , 13 -14 2011 CAD concurrent with MADe Jacek S. Stecki PHM Technology Pty Ltd 38

Conference AERONET "Aviation Valley" , 13 -14 2011 PHM Design Cycle Deliverables At the end of the risk assessment process, the user has knowledge of: How the system can fail (failure modes) How critical each failure is What are the causes of functional failures What are the interactions between functional failures What physical failures are linked to functional failure Where to place sensors – i. e sensor fusing How to monitor physical failures How to diagnose functional failure What is the expected reliability of the sensing system What is the expected functional and hardware reliability of the system Jacek S. Stecki PHM Technology Pty Ltd 39

Conference AERONET "Aviation Valley" , 13 -14 2011 Concluding Remarks Despite expectations the acceptance and effectiveness CBM is in question. To be effective: CBM/PHM programs must be designed and executed with the knowledge of the risks to which a system is exposed, i. e. the knowledge how the system fails Model-based failure analysis, defining failures dependencies and improving completeness of risk identifications, should be adopted in preference to spreadsheet and “spreadsheet” like FMECA methodology Model-based failure analysis should be adopted to enhance knowledge retention, knowledge transfer and to facilitate integration of risk assessment through supply chains Taxonomies of functions, failure concepts, components should be adopted to improve readability/portability of risk assessment results Diagnostic rules and Sensors sets should be selected on the basis of dependencies between failure modes (symptoms >>> syndrome) Clear hierarchy of failure concepts (cause> failure mechanism> fault> failure mode) should be enforced in risk assessment process Physical failures (cause/failure mechanism/fault) and their symptoms should form basis for BIT design Jacek S. Stecki PHM Technology Pty Ltd 40

Conference AERONET "Aviation Valley" , 13 -14 2011 Thank You! Jacek S. Stecki PHM Technology Pty Ltd 41