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

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Logistics Systems EngineeringSupportability

NTUSY-521-N

SMUSYS 7340

Dr. Jerrell T. Stracener, SAE Fellow

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Supportability

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

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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.

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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.

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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.

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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.

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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.

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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.

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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

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Definition

• The highest degree of supportability is achieved by1. Including supportability as a consideration of

the design process2. “Designing” and optimum set of support

resources3. Timely delivery of the set of support resources

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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

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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

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Supportability Requirements

Military Equipment

Industrial Equipment Consumer Equipment

Minimum DowntimeMinimum LCC

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Supportability Elements

• Supportability has three elements1. Support to design activity

Requirements DevelopmentDesign InputEvaluation and Trade AnalysisResource IdentificationTest and Evaluation

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Supportability Elements

• Supportability has three elements2. Development of Support Resources (Products)

Trained PersonnelSupport EquipmentSupply Support

3. Fielding and Product Support

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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)

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Cost Considerations

Insert A

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How to Consider in System Design

• Methods of Incorporation– Contract Scope of Work– Management Commitment– Designer Commitment– Tester Commitment

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Supportability During Design

Conceptual Initial FinalObjective:

Minimum DowntimeMinimum LCC

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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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Insert T 313-15

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Insert T 313-16

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• Specialties and their qualifications– All supportability specialties

ReliabilityMaintainabilityTestabilityILS ManagementLCC/Downtime/AvailabilityLSA/LSARAll support disciplines (Tech writing supply

support etc.)

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• All specialties must be experienced in operations and support and also experienced in design

• Baseline information and data requirements– Operation Scenario

Number of operational sitesNumber of operational systemsLocation of operational sitesOperating hours per system per monthPlanned Operational Life

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• Baseline information and data requirements (continue)– Maintenance and Support Scenario

Planned levels of maintenancePipeline timesContractor or customer organic

maintenanceSkills availableWarranty Requirements

• O & S data from previous similar systems

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• 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

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• Outputs– Supportable design that fulfills mission

requirementsDocumented and justified VIA LCC and

Downtime– Integrated Support Plan

All preliminary supportability planningKeyed to design and fabrication schedulesKeyed to support resources need dates

– Estimate of cost to conduct supportability program

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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 specialties1. Reliability, Maintainability, LSA and LCC first– To defend conceptual design supportability

features– To pick up additional supportability features– To monitor design

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• Phase in specialties (continue)2. LSAR– Develop documented maintenance and

support analysis of each repairable item– Identification of all support resource

requirements3. Support Specialties– Development and delivery of support

resources

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Insert T 313-23

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• 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

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• 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

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• Support resources are not always available to support testing– Contractor pre operational support is

required, this includes:Contractor spare parts supportContractor personnel to support

maintenance and supportContractor Depot

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• Supportability Test– Monitor all testing to observe performance of

support resources– Update LSAR/Support resource as required– Develop workarounds for support resources

not available

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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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Insert T 313-28

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Other Processes

• MIL STD 1388-1A - Equipment

Insert B

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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 CredibilityRisk Management Tool

• 103 Program and Design Reviews– Synchronized with Design Review-Integral

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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

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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

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Barriers to Supportability by Design

• Knowledge of Program• Funding Available• Lack of Design Definition (“Catch 22”)• Personality Attributes• Management Commitment• Engineering Commitment• Funding

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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”

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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

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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 onDISCTapePromsEProms

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• 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

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• 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 languageCompilerHost Computer

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• DOD instruction 2167 requires– All of the key elements– A “computer resources integrates support

document”

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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

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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

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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-t

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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

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The System View

Product

•Spares•Technical Publications•Training•Support Equipment

•Availability•Sortie Generation Rates•Basing

•Reliability•Maintainability•Supportability•Testability

•Organization•Requirements•Schedule Maintenance•Unscheduled Maintenance

Operational

Concept

MaintenanceConcept

SupportConcept

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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.

• ExamplesSystem Entities Attributes ActivitiesTraf. Flow Cars Speed, Dist. Driving, DelaysBank Op. Customers Balance, Depositing

Credit Status WithdrawingComm.Message Length, Transmitting

Priority Receiving

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Types of Availability Measures

• Inherent Availability,

• Achieved Availaiblity,

Operational Availability,

MTTRcMTBF

MTBFAi

Ai

MTTRcpMTBF

MTBFAa

MLDTMTTRcpMTBF

MTBFAo

Aa

Ao

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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

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System Time Relationships

Insert graph: MIL-STD-721C

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System Supportability AnalysisSupply Support Analysis

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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.

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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.

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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

... 2, 1, 0,for

!);(

xx

tetxp

xt

where is the average number of outcomes per unit time, t is the time interval and e = 2.71828...

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Poisson Distribution

• Mean or Expected Value

• Variance and Standard Deviation of X

tXE

tXVar 2

t

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Poisson Distribution - Example

When a company tests new tires by driving themover difficult terrain, they find that flat tiresexternally caused occur on the average of once every 2000 miles. It is found also that the Poissonprocess yields a useful model. What is the probabilitythat in a given 500 mile test no more than one flatwill occur?

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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 involvedin the definition of X, and since the average is givenas one flat is 2000 miles, we have

miles 500in flat 4

1)( XEt

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The values assigned to and t depend on the unitof distance adopted. If we take one mile as the unit,then t = 500, = 0.0005, and t = 1/4. If we take1000 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.

)1()miles 500in flat 1( XPP

)1()0( pp

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97.04

54/1

e

!1

4/1

!0

4/1 104/1e

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Number of Failures Model:

• DefinitionIf T ~ E() and if X is the number of failures occurringin 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/

!x

et)xX(P)x(P

tx

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The Poisson Model:

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The Poisson Model: Probability Distribution Function

0 1 2 3 4 5 6 7 8

1.0

0.5

0.0

x

0y

ypF(x)

.135

.405

.675

.855

XxPF(x)

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The Poisson Model:

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The Poisson Model:

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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) = 0.945or about a 5% chance of not having enough spares!

Documents

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