Logistics Systems Engineering SMU SYS 7340 NTU SY-521-N Logistics Systems Engineering Supportability Dr. Jerrell T. Stracener, SAE Fellow

Supportability Definition Comments Supportability Requirements Supportability Elements Benefits Cost Consideration System Design Barriers Post Delivery Software and CALS

Definition Supportability (Military) is the degree to which system design characteristics and planned logistics resources including manpower meet system (operational and wartime utilization) requirements. Supportability (general) develops in the design and maintains in the field equipment Reliability, Maintainability, and Availability characteristics by providing personnel, supply and support equipment at the right place at the right time.

Definition Supportability (Commercial/Industrial) is commercial equivalents to “Resources, Operational”, etc. Key Words… Design Characteristics Planned Logistics Resources Operational / Utilization Requirements Key Goal… Meet all requirements in a safe, cost effective, and timely manner.

Definition Supportability Assessment is an evaluation of how well the composite of support considerations necessary to achieve the economical and effective support of a system for its life cycle meets stated quantitative and qualitative requirements. This includes integrated logistics support and logistic support related O & S cost considerations.

Definition Supportability Analysis (SA) is an iterative analytical process by which the logistic support necessary for a new (or modified) system is identified and evaluated. The SA constitutes the application of selected quantitative methods to: 1. Aid in the initial determination of supportability design. 2. Aid in various design alternatives. 3. Aid in the various elements of maintenance. 4. Aid in the final assessment of the system support.

Definition Supportability Related Design Factors are factors which include only the effects of an item’s design. Examples include inherent reliability and maintainability values, testability values, transportability characteristics etc. Supportability Factors are qualitative and quantitative indicators of supportability.

Definition Integrated Logistic Support is a composite of all support considerations necessary to assure the effective and economical support of a system for its life cycle. It is an integral part of all other aspects of system acquisition and operation. Integrated logistics support is characterized by harmony and coherence among all logistics elements.

Definition Design (Dictionary) To draw, lay out, or prepare a design To make a drawing, pattern or sketch of To create, fashion, execute or construct according to plan Design (Supportability): The practical application of the laws of nature to define an item that will perform an identified function Item must be producible Item must be supportable

Definition The highest degree of supportability is achieved by 1. Including supportability as a consideration of the design process 2. “Designing” and optimum set of support resources 3. Timely delivery of the set of support resources

Definition “I often say that when you can measure what you are speaking about and express it in numbers, you know something about it. But when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts advanced to the state of science, whatever the matter may be.” Lord Kelvin

Comments Traditional design is based on well defined laws Supportability is adequately defined There are no “well defined laws” for supportability The elements of supportability are adequately defined and quantified Supportability needs a Lord Kelvin to develop supportability dimensions These dimensions must be accepted by the entire community, producers and users These dimensions will most likely be functions of cost and readiness

Supportability Requirements Military Equipment Minimum Downtime Minimum LCC Industrial Equipment Consumer Equipment

Supportability Elements Supportability has three elements 1. Support to design activity Requirements Development Design Input Evaluation and Trade Analysis Resource Identification Test and Evaluation

Supportability Elements Supportability has three elements 2. Development of Support Resources (Products) Trained Personnel Support Equipment Supply Support 3. Fielding and Product Support

Benefits of Design For Supportability System Characteristics Inherent Reliability Easily Operable and Maintainable Support System Characteristics Adequate Supply of Trained Personnel Minimal / Low Cost Support Equipment Capitalize Existing Facilities Transportable Design Achieves Goals in: Availability Cost Effectiveness (LC and O & S)

Cost Considerations Insert A

How to Consider in System Design Methods of Incorporation Contract Scope of Work Management Commitment Designer Commitment Tester Commitment

Supportability During Design Conceptual Initial Final Objective: Minimum Downtime Minimum LCC

Supportability During Conceptual Design A system’s design establishes the basic requirement for support resources Support is a design parameter Support features must be included in the conceptual design

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Supportability During Conceptual Design Specialties and their qualifications All supportability specialties Reliability Maintainability Testability ILS Management LCC/Downtime/Availability LSA/LSAR All support disciplines (Tech writing supply support etc.)

Supportability During Conceptual Design All specialties must be experienced in operations and support and also experienced in design Baseline information and data requirements Operation Scenario Number of operational sites Number of operational systems Location of operational sites Operating hours per system per month Planned Operational Life

Supportability During Conceptual Design Baseline information and data requirements (continue) Maintenance and Support Scenario Planned levels of maintenance Pipeline times Contractor or customer organic maintenance Skills available Warranty Requirements O & S data from previous similar systems

Supportability During Conceptual Design Process Identify design for support requirements Configuration Reliability Maintainability and Testability Design/Support Trades Life Cycle Cost Availability/Downtime Baseline for estimates extrapolated from existing similar systems

Supportability During Conceptual Design Outputs Supportable design that fulfills mission requirements Documented and justified VIA LCC and Downtime Integrated Support Plan All preliminary supportability planning Keyed to design and fabrication schedules Keyed to support resources need dates Estimate of cost to conduct supportability program

Supportability During Initial Design Monitor decision to proceed/contract award for: Design changes that impact supportability Omissions/deletions of supportability elements/funding Update ISP accordingly Phase in specialties 1. Reliability, Maintainability, LSA and LCC first To defend conceptual design supportability features To pick up additional supportability features To monitor design

Supportability During Initial Design Phase in specialties (continue) 2. LSAR Develop documented maintenance and support analysis of each repairable item Identification of all support resource requirements 3. Support Specialties Development and delivery of support resources

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Supportability During Initial Design Integrated Logistics Support management team meetings Continually review schedule and interface Identify and resolve open issues and identified problems Update ISP LSAR Review Manufacture internal: all specialties review and accept each complete LSAR User: accept each LSAR and or LSA reports

Supportability During Initial Design Schedule Completed LSAR requires released drawing and LSAR approval Provisioning requires approved LSAR Technical manual preparation requires approved LSAR and completed provisioning Training requires the technical manual

Supportability During Initial Design Support resources are not always available to support testing Contractor pre operational support is required, this includes: Contractor spare parts support Contractor personnel to support maintenance and support Contractor Depot

Supportability During Initial Design Supportability Test Monitor all testing to observe performance of support resources Update LSAR/Support resource as required Develop workarounds for support resources not available

Supportability During Final Design Develop supportability design improvements Monitor all design updates Emphasize supportability for design updates Continue ILSMTS Update: ISP LSAR All support resources

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Other Processes MIL STD 1388-1A - Equipment Insert B

Program Planning and Control MIL STD 1388 101 Early Logistics Support Strategy Concept Phase Activity Required for Dem/Val Phase 102 Logistics Support Analysis Plan Germain to LSA Effort Living/Dynamic Document Program Credibility Risk Management Tool 103 Program and Design Reviews Synchronized with Design Review-Integral

Determination of Support Resources Req. 401 Task Analysis: Allows for detailed analysis of proposed designs, including: Operational and Maintenance Tasks Logistics Support Resources Training Requirements & Recommendations Supportability goal verification/justification for design change Risk Management (Logistic Resources) Transportability Analysis Provisioning Validation of Data and LSAR

Determination of Support Resources Req. 402 Early Fielding Analysis Determines effects on other systems, manpower, readiness, survivability 403 Post Production Support Analysis Post production support planning

Barriers to Supportability by Design Knowledge of Program Funding Available Lack of Design Definition (“Catch 22”) Personality Attributes Management Commitment Engineering Commitment Funding

Barriers to Supportability by Design Speed of Program Type and Scope of Technical Data (TM/TNG) Data Management (Volume of Data) Time for Resource Acquisition “Flash to Bang”

Post Delivery Supportability The real test of supportability Support resources The validity of the maintenance/support concept Updates are usually required Continue ILSMTS Monitor support resources performance Out of production support Phase Out Develop lessons learned

Operational Software Supportability Digital Electronics has invaded all equipment Automobiles Television Receivers Military and commercial equipment Digital electronics requires instructions (prog.) Programs reside as software on the host equipment on DISC Tape Proms EProms

Operational Software Supportability Software updates are required to: Correct errors Accommodate for mission changes Accommodate for design changes Without software update capability, equipment could die Software supportability, like hardware supportability must be planned from the outset otherwise updates can require complete redevelopment

Operational Software Supportability Fleet users require organic capability to update their software There are three key elements to software supportability Documentation Configuration control Common software tools Higher order language Compiler Host Computer

Operational Software Supportability DOD instruction 2167 requires All of the key elements A “computer resources integrates support document”

Computer-aided Acquisition & Logistics Support Application of digital capabilities to design and data development for DoD equipment CALS includes Engineering Drawings All reports and contract data Equipment specifications All logistics data

Computer-aided Acquisition & Logistics Support Data is interchanged and stored digitally assuring: Easy transmittal Simplified storage Rapid update Immediate access Possibly the greatest advance since the printing press

Conclusions and Recommendations This section has provided an overview of the activities related to supportability Supportability suffers from a dearth of the rigorous logic that has made the technical specialties so effective Supportability requires basic research to develop credible techniques based on its fundamental equation: R=e-lt

Conclusions and Recommendations Supportability is a design parameter, each engineering student needs a basic course in logistics as a part of the undergraduate engineering curriculum Each logistician needs some basic understanding of the design process

The System View Operational Concept Product Maintenance Support Availability Sortie Generation Rates Basing Product Reliability Maintainability Supportability Testability Maintenance Concept Support Concept Organization Requirements Schedule Maintenance Unscheduled Maintenance Spares Technical Publications Training Support Equipment

Concept of a System A system is defined as an aggregation or assemblage of objects joined in some regular interaction or interdependence, principally dynamic with changes over time. Systems are generally characterized by Entities, Attributes, and Activities. Examples System Entities Attributes Activities Traf. Flow Cars Speed, Dist. Driving, Delays Bank Op. Customers Balance, Depositing Credit Status Withdrawing Comm. Message Length, Transmitting Priority Receiving

Types of Availability Measures Inherent Availability, Achieved Availaiblity, Operational Availability,

Types of Availability Measures Where: MTBF is the Mean Time Between Failures MTTRc is the Mean Time To Repair: corrective MTTRcp is the Mean Time To Repair: corrective/preventative MLDT is the Mean Logistics Down Time

System Time Relationships Insert graph: MIL-STD-721C

System Supportability Analysis Supply Support Analysis

Properties of the Poisson Distribution 1. The number of outcomes occurring in one time interval or specified region is independent of the number that occurs in any other disjoint time interval or region of space. In this way we say that the Poisson process has no memory. 2. The probability that a single outcome will occur during a very short time interval or in a small region is proportional to the length of the time interval or the size of the region and does not depend on the number of outcomes occurring outside this time interval or region.

Properties of the Poisson Distribution 3. The probability that more than one outcome will occur in such a short time interval or fall in such a small region is negligible.

Poisson Distribution Definition - If X is the number of outcomes occurring during a Poisson experiment, then X has a Poisson distribution with probability mass function where  is the average number of outcomes per unit time, t is the time interval and e = 2.71828...

Poisson Distribution Mean or Expected Value Variance and Standard Deviation of X

Poisson Distribution - Example When a company tests new tires by driving them over difficult terrain, they find that flat tires externally caused occur on the average of once every 2000 miles. It is found also that the Poisson process yields a useful model. What is the probability that in a given 500 mile test no more than one flat will occur?

Poisson Distribution - Example Solution Here the variable t is distance, and the random variable of interest is X = number of flats in 500 miles Since E(X) is proportional to the time interval involved in the definition of X, and since the average is given as one flat is 2000 miles, we have

Poisson Distribution - Example Solution The values assigned to  and t depend on the unit of distance adopted. If we take one mile as the unit, then t = 500,  = 0.0005, and t = 1/4. If we take 1000 miles as the unit, then t = 1/2,  = 1/2, and again t = 1/4, and so on. The important thing is that t = 1/4, no matter what unit is chosen.

Poisson Distribution - Example Solution

Number of Failures Model: Definition If T ~ E() and if X is the number of failures occurring in an interval of time, t, then X ~ P(t/ ), the Poisson Distribution with Probability Mass Function given by: for x = 0, 1, ... , n Where  = 1/ is the Failure Rate The expected number of failures in time t is  = t = t/ 

The Poisson Model:

The Poisson Model: Probability Distribution Function 0 1 2 3 4 5 6 7 8 1.0 0.5 0.0 .135 .405 .675 .855

The Poisson Model:

The Poisson Model:

The Poisson Model - Example Application: Problem - An item has a failure rate of  = 0.002 failures per hour if the item is being put into service for a period of 1000 hours. What is the probability that 4 spares in stock will be sufficient? Solution - Expected number of failures (spares required) = t = 2 P(enough spares) = P(x  4) = p(0) + p(1) + p(2) + p(3) + p(4) = 0.945 or about a 5% chance of not having enough spares!