SMU
SYS 7340
NTU
SY-521-N
Logistics Systems Engineering
Supportability
Dr. Jerrell T. Stracener,
SAE Fellow
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Supportability
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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
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
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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
Minimum Downtime
Minimum LCC
Industrial Equipment
Consumer Equipment
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Supportability Elements
• Supportability has three elements
1. Support to design activity
Requirements Development
Design Input
Evaluation and Trade Analysis
Resource Identification
Test and Evaluation
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Supportability Elements
• Supportability has three elements
2. Development of Support Resources
(Products)
Trained Personnel
Support Equipment
Supply 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
Final
Objective:
Minimum Downtime
Minimum 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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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.)
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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
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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
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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
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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
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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 specialties
1. 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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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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Insert T 313-23
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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
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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
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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
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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
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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 Credibility
Risk 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
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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
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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 on
DISC
Tape
Proms
EProms
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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
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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
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Operational Software Supportability
• 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-lt
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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
Operational
Concept
•Availability
•Sortie Generation Rates
•Basing
Product
Maintenance
Concept
•Organization
•Requirements
•Schedule Maintenance
•Unscheduled Maintenance
•Reliability
•Maintainability
•Supportability
•Testability
Support
Concept
•Spares
•Technical Publications
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•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
Traf. Flow
Bank Op.
Entities
Cars
Customers
Comm.
Message
Attributes
Speed, Dist.
Balance,
Credit Status
Length,
Priority
Activities
Driving, Delays
Depositing
Withdrawing
Transmitting
Receiving
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Types of Availability Measures
• Inherent Availability,
Ai
MTBF
Ai 
MTBF  MTTRc
• Achieved Availaiblity,
Aa
MTBF
Aa 
MTBF  MTTRcp
Operational Availability,
Ao
MTBF
Ao 
MTBF  MTTRcp  MLDT
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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 Analysis
Supply 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
p( x; lt ) 
e
 lt
lt 
x
x!
for x  0, 1, 2, ...
where l 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
  E X   lt
• Variance and Standard Deviation of X
Var X     lt
2
  lt
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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?
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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 involved
in the definition of X, and since the average is given
as one flat is 2000 miles, we have
1
lt  E ( X )  flat in 500 miles
4
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Poisson Distribution - Example Solution
The values assigned to l and lt depend on the unit
of distance adopted. If we take one mile as the unit,
then t = 500, l = 0.0005, and lt = 1/4. If we take
1000 miles as the unit, then t = 1/2, l = 1/2, and
again lt = 1/4, and so on. The important thing is
that lt = 1/4, no matter what unit is chosen.
P( 1 flat in 500 miles )  P( X  1)
 p(0)  p(1)
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Poisson Distribution - Example Solution
0
1


1 / 4 
1 / 4 1 / 4 
e 


1! 
 0!
5 
 1/ 4  0.97
4e
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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:

lt 
P( x )  P(X  x ) 
x
e
x!
 lt
for x = 0, 1, ... , n
Where l = 1/ is the Failure Rate
• The expected number of failures in time t is
 = lt = t/ 
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The Poisson Model:
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The Poisson Model: Probability Distribution Function
1.0
F(x)  Px  X
.855
x
F(x)   py 
.675
y 0
0.5
.405
.135
0.0
0
1
2
3
4
5
6
7
8
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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 l = 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) = lt = 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!
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