The Intermittent Connection THE REAL STORY

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Interactive Web Links www.usynaptics.com
E-mail engineering_at_usynaptics.com
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Universal SynapticsTHE INTERMITTENT CONNECTION
Aging Wiring
What are the Failure Modes?
How do Systems Age?
Developing a Perspective of the Problem...
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Some think the aging wiring problem looks like
this
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But we were left wondering who ATE the other
half of the Pie?
Pilot reported malfunctions neither detected
nor repaired with traditional test equipment!
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The Name GameIntermittent failures have another
new name

• NFF - No Fault Found
• ER - Erroneous Removal
• NPF - No Problem Found
• CND - Can Not Duplicate
• RETOK - Re-Test OK
• NEOF - No Evidence Of Failure

Change the name, fix the problem?
Interactive Web Link Intermittence and its
Labels
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Other comprehensive studies show the circuit
interconnections to be a much larger
problem The following results from the AF
Safety Agency are more in line with our
experiences. In either case, dont forget that
other half of the problem No Fault Found!
Interactive Web Links Review of Federal Programs
For Wire System Safety
NASAs SIAT Report
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AF Mishap Data forElectronic Related Failures
(1989-99)
System
Function
Unknown
Electronics
Avionics
Interconnections
Flight Control
Power Systems
Fuel Systems
Instruments
Electromechanical
Data provided by the AF Safety Agency
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AF Mishap Data forElectronic Related Failures
(1989-99)
Connectivity Elements 63
Data provided by the AF Safety Agency
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AF Mishap Data forElectronic Related Failures
(1989-99)
Function of Failed Component by Aircraft Type
Interconnections
Electronic Electromechanical
Data provided by the AF Safety Agency
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These studies are helpful, but its really not
about components. They are all similar And they
all wear out in a similar manner. Its not a
component problem, its a TESTING PROBLEM!!!
Aging / Intermittent Components
They Just Dont Fit!
Its a round problem, trying to be solved with a
square solution!
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How Electronic Systems Age

• Aging is a normal process caused by repeated
  exposure to normal environmental conditions.
• The Aging process denotes a degradation over
  time.
• Rarely are aircraft elements fully functional
  one moment and completely open or shorted (hard
  failure) another.
• Instead, these aging elements enter a phase of
  intermittency.
• This failure type is not easily detected with
  traditional test equipment because of its random
  and often infrequent nature.

Interactive Web Link How Parts and Systems Age
(Aviationtoday.com)
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• If it Cant be Detected, it Cant be Fixed

No Fault Found (NFF) rates are a measurement of
this aging / intermittency problem.
Interactive Web Link Nanosecond Intermittency
(amp.com)
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Coming to terms with the problemThere are only
two kinds of failures

• 1. HARD FAILURES
• Repeatedly demonstrates the fault
• ATE or other testers detect the failure
• Diagnostic programs isolate the fault
• 2. INTERMITTENT FAILURES
• Randomly demonstrates the failure
• Seen as SYSTEM failures that ATE can't detect
• Diagnostics won't work, must use "Swapnostics
• Cause of most NFF failures in older systems
• Also include "Hard" failures that were
  intermittently failing, units that fail shortly
  after installation and all units that test OK or
  "No Fault Found" (NFF).

Aging systems are usually intermittent long
before they become Hard Failures!
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Intermittent Failure TypesThere are three kinds
of intermittent failures

• 1. Engineering
• Complex interactions between various components
  and certain timing events cause a circuit to
  temporarily deliver the wrong output. Usually
  associated with a fault syndrome. (Generally rare
  and usually fixed when a system is new.)
• 2. Test Void
• UUT continuously fails a test or function at a
  high level. The fault is not detectable at a
  lower level. (Easy to fix.)
• 3. Interconnections
• A randomly occurring, temporary change in
  connectivity, usually induced by mechanical or
  thermal events. Generally gets worse over time
  due to wear and corrosion. (Randomness makes it
  hard to duplicate while testing.)

They change over time...
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• But Testing Stays The Same
• Problems Are Being Missed!
• Reliability Suffers.
• Systems Become Worn Out

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Testing StructureThe Missing Link
All Failures
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50
Intermittent Aging / NFF
Failures
Hard Failures
80
10
10
Loose / Contaminated Inter-Connections
Design Defects
Repeatable Test Voids
Engineering Staff
Programming Staff
Connector Pins
Solder Joints
Full Testing ATE, System
Full Testing ATE, System
Test Light Ohmmeter
Magnify Glass Solder Iron
OEM Support
OEM Support
IFD-2000 Intermittent Fault Detector
40 Billion DOD Test Equipment Inventory
The testing imbalance for older systems
Source Defense Electronics Magazine
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Testing PrioritiesWhat We Think Were Testing

• Official Strategy
• "If the cost of failure (total cost of a crash)
  exceeds the cost of test and repair then we
  test.
• "This strategy provides a basis for testing
  first for those conditions that are likely to
  cause an expensive failure.
• "We should design our test so that we test for
  the most probable faults first and continue
  testing until the remaining untested potential
  faults are not of economic concern.
• Remarks by Duane Allen, Measurement Science
  Directorate, Naval Warfare Assessment Station, at
  AutoTestCon98 based on the work of Demming.

Test for the faults that present the highest risk.
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Testing PrioritiesWhat should be tested?

• Reality
• As a system ages, intermittent type failures
  become the most probable and abundant failure
  mode, but are not even included in the testing
  strategy.
• Testing programs and test equipment specified
  when a system is new are the same throughout the
  life of the system, yet the failure types change
  drastically.
• Current studies on Aging continue to ignore even
  the possibility of intermittency as a failure
  mode.
• Some mind-sets dont believe that intermittents
  hazard an aircraft!

Systems require reliability/intermittency testing
as they age
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Testing PrioritiesThe Dichotomy

• Functional testing has little to do with
  reliability!
• Functional testing only ensures that the UUT is
  working properly at that given point in time. It
  only looks for compliance with engineering
  standards.
• Aging failure mechanisms manifest themselves as
  intermittent failures and basically have no
  testing standards.
• With no testing standards there is no testing.
• With no testing there is no sustained reliability.

We need to have intermittency standards, and
intermittence must be included in all on-going
aging studies and testbeds.
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• What the Technical Experts are Saying
• No Fault Found Frustrations and the problems
  testing it
• It is fair to say that the nature and design of
  a test automatically predetermines the result.
  Applies to Aging studies with no intermittence
  testbeds or intermittence detection capable
  equipment!
• Intermittence Testing...
• Only massively parallel and true analog
  analysis can even hope to detect and correctly
  identify this problem Universal Synaptics
  Corp. now provides a massively parallel
  intermittent fault detector to do analysis of
  everything from internal unit wiring to airframe
  harnesses in situ..
• - Walter Shawlee 2, Technical
  Writer, Avionics Magazine
• Defeat Intermittents editorial in TMW...
• Universal Synaptics has a neat piece of
  high-tech test equipment The company is small,
  but my recent visit convinced me that what it
  lacks in size it makes up for in technology and
  the ability to accurately locate intermittent
  problems I saw their equipment and it works!
• - John Titus, Editorial
  Director, Test Measurement World

Interactive Web Link Connector Science (amp.com)
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Problems w/Test EquipmentATE, Continuity, TDR,
SWR
Scanning
Synchronization
UUT
Random Intermittent
Measure
Test Window
Sampling
No Stress
Filtering
They can't see intermittency
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Which of These Testing Problems Does the Test
Equipment You Are Currently Using Suffer
From? Think About It... Be Absolutely Sure...
Its Critical to Fixing the Entire Problem!
Interactive Web Link Detecting Intermittence
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The Testing SolutionSo What is This IFD-2000?

• Its a highly sensitive, parallel analog
  hardware neural network with patented all test
  points all the time measurement technology.
• Its massively parallel 256 test points per
  module, up to 40,000.
• No Scanning! If any circuit under test exhibits
  an anomaly you WILL be measuring that line.
• Its Analog true, continuous, measurement.
• The only way to test for randomly occurring,
  low-level, aging / intermittent / NFF anomalies.
• Its real-time testing method is similar to how
  avionics work in the real world all test
  points, all the time.

Interactive Web Link IFD-2000 White Paper
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Testing for Random FaultsIFD-2000 vs. ATE, TDR,
and Continuity testers
ATE
Digital Technology
Measures only onepoint at a time,filters small
anomalies
Missesevents!
Intermittent Event
Analog Technology
Nomissedevents
No scanning
High sensitivity
No cable limits, Works in Noisy Environments,
Safe Low-Voltage Stimulus
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Testing for Random Faults
Pilots see all systems all the time. No Missed
Events!
Analog Technology
Nomissedevents
No scanning
High sensitivity
See the similarities? Both are all points all
the Time!
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• When all components/elements of a system are
  tested all at once, over some period of time...
  not just briefly... confidence in the reliability
  of that system as a whole is greatly increased
• Testing that separates all the pieces and then
  only tests them serially for a few micro
  seconds... is totally DIFFERENT than how they are
  used in the aircraft This method works great for
  hard failures but does little for reliability and
  confidence.
• The IFD-2000 Hardware Neural Network testing
  technology essentially tests all wires,
  components, systems... all together, over a
  longer time period, just like in actual
  operation... tests are not supposed to be quick,
  but should last long enough to detect those
  problems that may develop well into flight.
• The IFD-2000 restores that quality of testing
  which was taken away by the introduction of
  digital/serial (ATE) testing and therefore is the
  right testing adjunct to fix the aging/testing
  problem.
• With both digital (ATE) and analog (IFD)
  technologies combined, great synergistic benefits
  are derived which resolves the testing
  deficiencies related to aging electronics, and
  should be applied at every maintenance level.

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INTERMITTENCE TESTING METRICSComparing the
TechnologiesBased on a Wide Range of Real World
Testing Scenarios
Hi-Speed
ATE
IFD-2000
Digital
Continuity
The IFD-2000 Enables Reliability Testing In-Situ
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Intermittent Fault Detector A comparison of
capabilities Inertial Navigation Computer A22 SRU
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A total of 26 units were tested The IFD-2000
detected and tagged 14 units as being
intermittent. After running much longer than
normal, 8 of the 14 units eventually failed the
analog system simulator. Only 2 units failed the
ATE test stands. Four of the intermittent units
passed all regular system tests.
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26
20
15
14
10
8
5
2
0
Units Tested
IFD-2000
System Simulator (Analog)
SRU-ATE (Digital)
ATE failed miserably!
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Portable
Bench
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Testing with the IFD-2000Adapter requirements
IFD-2000
Simple one wire per test point method uses a
single common return path at the other end of the
aircraft.
DRIVERSENSORS
Safe 0 to 3.5 Volts Stimuli
Unit Under Test
GND RETURN LINE
TEST ADAPTER
Flexibility allows IFD-2000 to adapt to various
requirements
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Interactive Web Link IFD-2000 Specifications
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IFD-2000 OperationIntermittence, Continuity,
Scope, Z-Sweep and more..
1Connect LRU
2Build Map File
3TestSetup
4 Run It
Easy to setup and run, user friendly
Interactive Web Link Using the IFD-2000
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ANALYZE Continuity Test
Analyze is a proprietary, continuity-like test
which looks at all connected lines and compares
the results to a previously saved good, or
Gold file. Any deviations from the gold are
noted graphically with a raised column on the
tested line which is scaled for impedance
variations. Gold files may be archived to
monitor long-term aging/drift over time. At the
end of testing, formalized reports are generated
for proof of testing as well as archival/trending
purposes.
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INTERMITTENT FAULT DETECTION
Intermittent Fault Detection monitors all
connected lines, all-the-time, sensing for
changes in connectivity. Drive(D) and
Sensitivity(S) levels are programmable to allow
adaptation to a variety of testing requirements.
Anomalous events are noted by a raised column
which grows in relation to the number of times
the particular circuit has gone intermittent.
A voice synthesizer also calls out the location
of the intermittence using map file terminology.
Wireless headphones enable a single operator to
get far from the tester to apply external
stimulus if needed. At the end of testing,
formalized reports are generated.
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SCOPE MODE Slow-Motion Intermittence
Scope mode is used to characterize
slower-moving intermittencies... the type that
tend to drift slowly over longer time periods
such as with weak/dirty contacts, switch bounce,
etc. Measurements are graphically displayed and
any deviations from the gold are tabulated and
included in the testing report.
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Z-SWEEP MODE Impedance Sweep
Z-Sweep mode uses proprietary sweep stimuli to
test/excite electronic components such as
resistors, capacitors, filters, inductors,
transformers, diodes, etc., similar to other
frequency type, pattern diagnostic equipment.
Measurements are graphically displayed and any
deviations from the gold are tabulated and
included in the testing report. Signature
patterns may be archived to monitor long-term
aging/drift over time.
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IFD-2000 VersatilityDiagnostic Workstation
Any PC Add-on
Work Flow Documents
IFD-2000
PC
AI Diagnostics
Aircraft Bus Analyzer
Parts Database
Tech Manuals
TDR
Intermittency
ATPG for ATE
Continuity
Wirelist Schematicson-the-fly
Scope
Neural Net Diagnostics
Z-Sweep
Open system for commercial add-ons...Augments ATE
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Testing with the IFD-2000Adapter requirements
IFD-2000
One adapter does all
By placing a variety of pins on an extension
cable, diagnostics could be performed on numerous
circuits without the necessity of building an
adapter for each one.
Generic adapters for diagnostics or limited
testing.
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Costs ATE - IFD-2000Cost of Ownership - 10
years
Based on testing 40 different, medium complexity,
LRUs
Interactive Web Link Operating Software
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DEPOT SUSTAINMENT COST DRIVERS

• The Air Force Spends
• 41 of its Depot OS
• Dollars on Avionics
• More Than it Spends
• on Any Other Item

Battelle data for 1996

Source USAF Aging Aircraft Support Group
Interactive Web Link Diagnostic/Testing Software
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PROJECTED AIRCRAFT LIFE CYCLES
36 Years
F-15
41 Years
F-16
43 Years
F-22
89 Years
B-52
41 Years
C-141
72 Years
C-5
59 Years
C-17
63 Years
A-10
1950
1970
1990
2010
2030
2050
Source USAF Aging Aircraft Support Group
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Reducing RisksWhat does an IFD-2000 cost?

• Cost of IFD-2000 49,000
• Spread over 50 aircraft 980
• Spread over 5 years 196
• To protect ,000,000,000
• And maintenance savings alone pays for it all and
  more!

Costs less than auto insurance...
Interactive Web Link IFD-2000 Pricing