IEC TS 62500:2008

IEC/TS 62500
Edition 1.0 2008-07
TECHNICAL
SPECIFICATION
Process management for avionics – Defining and performing highly accelerated
tests in aerospace systems – Application guide

IEC/TS 62500:2008(E)
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IEC/TS 62500
Edition 1.0 2008-07
TECHNICAL
SPECIFICATION
Process management for avionics – Defining and performing highly accelerated
tests in aerospace systems – Application guide

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
W
ICS 03.100.50; 31.020; 49.060 ISBN 2-8318-9933-8
– 2 – TS 62500 © IEC:2008(E)
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Terms and definitions .7
3 Acronyms .9
4 Highly accelerated test goals and principles .10
4.1 General characteristics.10
4.2 General principles of highly accelerated tests.11
4.3 Example of the limitations of highly accelerated tests .13
5 Industrial technical domains covered by highly accelerated tests.14
6 Highly accelerated tests in the lifecycle and associated assembly levels .14
7 Planning and management of highly accelerated tests.16
7.1 General .16
7.2 Validation and verification .16
7.3 Planning of highly accelerated tests .17
7.4 Management of highly accelerated tests.18
8 General methodology for implementing highly accelerated tests .18
8.1 Structure of the approach .18
8.2 Analysis of product sensitive points.19
8.3 Selection of applicable stresses .20
8.4 Producing a test plan.21
8.5 Performing tests .23
8.6 Analysis of test results, corrective action and resumption of testing.24
9 Building on and using experience .24
9.1 General .24
9.2 Creating the database .25
9.3 Inclusion in the company reference system .25
9.4 Use of results for environmental stress screening.25
9.5 Correlation with feedback .26
9.6 Synthesis and impact on company culture .26
10 Customer/supplier relations .26
10.1 Prime contractor/supplier relations .26
10.1.1 Responsibilities .26
10.1.2 Contract procedures .27
10.1.3 Tests synthesis.27
10.2 Supplier/test laboratory relations .27
11 Costs and savings .28
11.1 General .28
11.2 "Non-reliability" costs .28
11.2.1 Cost in delayed time to market .28
11.2.2 Cost of an in-service failure .29
11.2.3 Cost of a recovery operation.30
11.2.4 Impact on brand image .30
11.3 Expenses generated by the highly accelerated tests.30
11.3.1 Engineering upstream of testing .30

TS 62500 © IEC:2008(E) – 3 –
11.3.2 Test resources used .31
11.3.3 Manpower dedicated to highly accelerated tests .31
11.3.4 The cost of damaged or destroyed products .31
Annex A (informative) Comparative characteristics of highly accelerated tests and
reliability tests .32
Annex B (informative) Example of potential effectiveness table for stresses or loadings
according to the nature of the product sensitive point .33
Annex C (normative) Highly accelerated tests implementation logic .34
Annex D (informative) Margin-related statistical considerations – Example:
telecommunications circuit boards or board assembly.36
Bibliography.38

Figure 1 – Exploration of margins using a highly accelerated test .13
Figure 2 – Financial losses generated by a delay in time to market.29
Figure C.1 – General logical flowchart .34
Figure C.2 – Details of test performance.35
Figure D.1 – Examples of the margin options open to the designer .37

Table A.1 – Comparative characteristics of highly accelerated tests and reliability
tests .32
Table B.1 – Example of potential effectiveness table for stresses or loadings according
to the nature of the product sensitive point .33

– 4 – TS 62500 © IEC:2008(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PROCESS MANAGEMENT FOR AVIONICS –
DEFINING AND PERFORMING HIGHLY
ACCELERATED TESTS IN AEROSPACE SYSTEMS –
APPLICATION GUIDE
FOREWORD
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The main task of IEC technical committees is to prepare International Standards. In
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specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC 62500, which is a technical specification, has been prepared by IEC technical committee
107: Process management for avionics.

TS 62500 © IEC:2008(E) – 5 –
This technical specification cancels and replaces IEC/PAS 62500 published in 2006. This first
edition constitutes a technical revision.
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
107/79/DTS 107/90/RVC
Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

– 6 – TS 62500 © IEC:2008(E)
INTRODUCTION
In an increasingly harsh economic context (tighter performance requirements, shorter
development cycles, reduced cost of ownership, etc.), it is essential to ensure product
maturity rapidly and, in any case, by the time of commissioning.
It is with a view to remedying shortcomings in traditional development methods that "highly
accelerated" tests have been developed. The main underlying principle behind this new type
of test strategy is as follows: rather than reasoning in terms of conformity with a specification
and simply performing conventional tests, it is on the contrary attempted to push the product
to its limits by applying environmental stresses and/or stimuli of levels higher than the
specification. The aim is thus to take full advantage of current technologies, by eliminating
defects which generate potential failures, as of the first prototypes.
A well-conducted accelerated test process should, in a relatively short time, lead to a
significant increase in the robustness of a product, as early as the initial prototypes stage at
the beginning of the development phase, thus accelerating early maturity of this product.
Furthermore, identification of the margins available on a "mature" product helps to design and
size its future environmental stress screening profile more accurately, by increasing the
severity of the loadings applied to just what is needed, leading to a particularly significant
boost in the efficiency of this environmental stress screening process.

TS 62500 © IEC:2008(E) – 7 –
PROCESS MANAGEMENT FOR AVIONICS –
DEFINING AND PERFORMING HIGHLY
ACCELERATED TESTS IN AEROSPACE SYSTEMS –
APPLICATION GUIDE
1 Scope
This technical specification specifies the targets assigned to highly accelerated tests, their
basic principles, their scope of application and their implementation procedures. It is primarily
intended for programme managers, designers, test managers, and RAMS experts to facilitate
the draft of the specification and execution of highly accelerated tests. This guide is
applicable to all programmes and is of primary interest to the industrial firms in charge of
designing, developing and producing equipment built for these programmes, and also their
customers who, in drafting contractual clauses, may require that their suppliers implement
highly accelerated tests.
NOTE This technical specification applies to all types of equipment used in systems developed in these
programmes, whatever their nature (electronic, electromechanical, mechanical, electro-hydraulic, electro-
pneumatic, etc.) and whatever their size, from "low-level" subassemblies (PCBs, mechanical assemblies,
connectors, etc.), up to system level groups of equipment.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE Most of the terminology used in this technical specification conforms to that used in Recommendation
RG.Aéro 000 27. For the other terms, it relies on those used in other documents, such as ET 99.04 (see
Bibliography).
2.1
step stressing
gradual step-wise increase in the level of stress applied to a product
2.2
hard failure
failure which does not disappear on returning to a lower stress level and which can only be
eliminated by repair
2.3
soft failure
failure appearing after a certain given stress level, which disappears when the stress falls
back below this level
2.4
extrinsic defect
fault or weakness inherent in the design of a product or its manufacturing processes and the
elimination of which, presumed to be economically feasible, leads to an improvement in its
operating and/or destruction margins
NOTE This type of defect, which is always the result of a deviation from standard best practices, is not by
definition related to the intrinsic limit imposed by the technologies used.
2.5
intrinsic defect
defect related to the component design, materials, processing, assembly or packaging and
provoked under circumstances within the component's design specifications

– 8 – TS 62500 © IEC:2008(E)
2.6
latent defect
defect which originally exists in the equipment but has not yet been precipitated and is thus
as yet undetectable by conventional performance checks on this equipment
2.7
patent defect
defect in a component which, after being precipitated, has become detectable by conventional
performance checks
NOTE A patent defect thus stems from a latent defect which has evolved following application of appropriate
stresses (e.g. temperature, vibrations, etc.) and which thus becomes detectable by a performance check.
2.8
environmental stress screening
ESS
set of production process tasks consisting in applying to the equipment concerned, within the
limits permitted by its design, particular environmental stresses in order – during
manufacturing – to reveal and eliminate the largest possible number of extrinsic defects
which, in all probability, would have appeared once utilisation had begun (early life failures)
2.9
accelerated test
test, the aim of which is to predict the behaviour and/or lifetime of a product in its operational
conditions of use, by subjecting it to stresses harsher than the values expected during its
lifespan profile
NOTE Contrary to highly accelerated testing, a "conventional" accelerated test (time/stress exchange) always
relies on one or more analytical lifetime and damage models.
2.10
highly accelerated test
test during which the product or some of its component parts are subjected to environmental
and/or operating stresses that are increased progressively to values far in excess of the
specified values, up to the operating and/or destruction limits of the product
NOTE The rise in exposure time or number of cycles, whether or not associated with a combination of certain
stresses raised to values close to or equal to the specification (or stresses whose nature is not specified) may
meet the same targets as those of the highly accelerated tests, as defined in this technical specification.
2.11
reliability
ability of a product to perform a required function, in given conditions, for a given time interval
NOTE This characteristic is generally expressed by a probability.
2.12
destruction limit
level of stress above which the product will suffer irreversible damage and will no longer be in
conformity with nominal performance once the stress level is returned to below the specified
value (notion of irreversibility)
2.13
operating limit
stress level above which the product no longer functions nominally. When the stress is
returned to below this level, product performance returns to nominal (notion of reversibility)

TS 62500 © IEC:2008(E) – 9 –
2.14
fundamental limit
intrinsic limit determined by the technology of a product or particular component, with respect
to a given stress (temperature, vibration, electrical voltage, etc.). This limit, whether or not
destructive, is an absolute barrier and cannot therefore be attributed to a extrinsic defect
EXAMPLE: Melting temperature of a plastic, maximum junction temperature of a semiconductor, yield strength of a
material, etc.
2.15
operating margin
for a given stress, difference between the operating limit and the specification
2.16
destruct margin
for a given stress, difference between the destruct limit and the specification
2.17
maturity
attainment of a product status for which its functional and operational performance can be
considered stabilised with respect to the specifications
NOTE Maturity is the result of a gradual process of eliminating extrinsic defects still present in the product and
the associated processes. This process is called maturing.
2.18
precipitation
transformation, using appropriate stresses, of a latent defect (not yet detectable) into a patent
defect (detectable)
2.19
robustness
property of a product indicating reduced sensitivity of its performance to changes in the
environmental stresses to which it is subjected, to component variation and to drifts in its
manufacturing processes
NOTE Robustness to a large extent is the result of action taken to obtain sufficient operating margins while at the
same time reducing all forms of variability.
2.20
reliability, availability, maintainability, safety
RAMS
range of capabilities of a product enabling it to achieve specified functional performance, at
the required time, for the required duration, without damage to itself or its environment

2.21
failure modes and effects analysis
FMEA
qualitative method of reliability analysis which involves the study of the fault modes which can
exist in every sub-item of the item and the determination of the effects of each fault mode on
other sub-items of the item and on the required functions of the item
3 Acronyms
• CDR: Critical Design Review.
• FMEA: Failure Modes and Effects Analysis.
• EMC: Electromagnetic Compatibility.
• ESS: Environmental Stress Screening.

– 10 – TS 62500 © IEC:2008(E)
• FRACAS: Failure Reporting and Corrective Action System.
• HAT: Highly Accelerated Test
• MTBF: Mean Time Between Failures.
• PCB: Printed Circuit Board.
• PDR: Preliminary Design Review.
• PRA: Preliminary Risk Analysis.
• RAMS: Reliability, Availability, Maintainability, Safety.
• RS: Requirements Specification.
• RTV: Rapid Temperature Variation.
• TTM: Time To Market.
4 Highly accelerated test goals and principles
4.1 General characteristics
A highly accelerated test is a test in which the product or some of its component parts are
subjected to environmental and/or operating stresses which are gradually raised to values in
excess of the specified values, until the product operating and/or destruction limits are
reached.
The primary purpose of highly accelerated tests is to contribute to:
– improving the robustness of the product, by eliminating the weaknesses inherent in the
product design and/or processes, and in the technologies used;
– obtaining products that are mature as of the first production article;
– improving the reliability and lifespan of the product in service;
– reducing development times and costs;
– specifying optimal environmental stress screening.
Attaining these goals involves:
– detecting extrinsic defects as early as possible (so that they can be corrected), as these
defects are inherent in design errors or insufficient control of the manufacturing
processes,
– exploration of the operating limits, once extrinsic defects have been eliminated so that,
whenever applicable, they can be pushed back through new design choices, when the
margins in relation to the specified operating range appear inadequate.
Instead of reasoning in terms of conformity with the specification, which is a poor way of
reflecting the product's real lifespan profile, it is on the contrary attempted to push the product
to breaking point (often up to failure), using environmental stresses or various stimuli at levels
far in excess of the specifications, in order to reveal, identify, then correct the extrinsic
defects still present. This implies on the one hand exploration of the available margins, and
on the other, improving these margins through appropriate action on the design of the product
itself or its manufacturing processes (see Annex D).
Owing to the adopted definition for the highly accelerated test, the following characteristics of
this type of highly accelerated test can be identified:
– A highly accelerated test is a proactive type of test: it is here understood that a highly
accelerated test should be considered as a tool to support the design of the product and
its processes and that it normally leads to engineering activities aimed at understanding
the failure mechanisms observed, in order to provide the corrections felt to be
economically feasible and which will enable them to be eliminated or at least delay their

TS 62500 © IEC:2008(E) – 11 –
evolution. The highly accelerated test is "proactive" in that it encourages these
engineering actions at the earliest stage in development.
– A highly accelerated test is not a conformity test: through the desire to explore the
margins and expand them if necessary, the highly accelerated test looks above all to
reveal the product defects which generate failures when working beyond the
specifications. It is therefore the opposite of a conformity test, which simply aims to
ensure that the product's performance is correct when it is subjected to the specific
operating and environmental conditions.
– A highly accelerated test should not be confused with an ordinary margins
verification test: a margins verification test in fact simply aims to ensure that product
performance remains correct when the stress values are raised to predetermined values
above the specified values, whatever the initially adopted margin. Consequently, the
margins verification test consists in practice in applying an extra coefficient to certain
specified stresses (referred to as the "regulation coefficient" in certain mechanical
professions). It is similar to a conformity test, even if it deals with performance conformity
in operating conditions which are outside the specified range. The highly accelerated test,
for its part, establishes operating and/or destruction margins for the product.
– A highly accelerated test should not be confused with a "conventional" accelerated
lifespan test: the purpose of an accelerated lifespan test is in fact to predict the evolution
of the behaviour of a product in its operational conditions of use, by subjecting it to
stresses that are harsher than the values expected during its lifespan profile. To do this,
the accelerated test relies on analytical product failure mode acceleration models, which is
not the case with the highly accelerated test.
– A highly accelerated test cannot produce reliability measures: as the highly
accelerated test works outside the specified domains, the analytical acceleration models
can no longer apply to the domains explored. Furthermore, it is very hard to involve the
"time" factor given the very short duration of the test. The result is that as things currently
stand, the highly accelerated test cannot be used to estimate product reliability or lifetime
characteristics in the specified conditions of use.
Annex A specifies the characteristics of a highly accelerated test versus a growth, validation
and reliability qualification test.
4.2 General principles of highly accelerated tests
As a design tool, the highly accelerated test aims – through application of stresses going
beyond the specification or simply not specified – to stimulate all the weak points in the
product design during development and in its manufacturing processes. Revealing these weak
points is thus an opportunity to improve the product or processes more quickly than with a
traditional approach, leading to an expansion of the operating margins and thus greater
reliability.
It is important to understand that in a highly accelerated test, the stresses applied are chosen
so as to actively stimulate the defects and weak points of the product and its processes, and
are not therefore designed to simulate the conditions of use of the product during its lifespan
profile. These stresses are applied either alone or combined, well past the values expected
during the lifespan of the product, until they reach the fundamental intrinsic limit set by the
technology. This implies gradually eliminating the various barriers preventing this limit from
being reached and which are due to the existence of any weak points still present (extrinsic
defects). An essential goal of the highly accelerated test is precisely to reveal the existence of
these extrinsic defects, even when they lead to a malfunction of the product used beyond its
qualification conditions.
Among the reasons, which justify the desire to correct extrinsic defects, which only trigger
malfunctions in out-of-specification product operating conditions, the following could be
mentioned:
– 12 – TS 62500 © IEC:2008(E)
– the experience built up by companies that use highly accelerated tests shows that most
malfunctions detected during these tests end up being detected in the field, if the extrinsic
defects revealed by these tests are not eliminated;
– there is often a considerable gap between the specification conditions and the actual
conditions of use of a product, in particular if there is a wide variety of a product usage.
Consequently, certain lifespan profile situations, sometimes very short, require the product
to operate in severity conditions far beyond the specified coverage;
– experience shows that extrinsic defects can often be easily located and can be eliminated
or attenuated both easily and economically (e.g.: insufficient component size,
inadequately tightened screw, components mounted on vibrating parts of a PCB, PCB
inadequately secured in a unit subject to vibration, weakness of a mechanical link, etc.).
Owing to its damaging nature, the principle of the highly accelerated test is thus a cultural
sea-change in relation to the traditional approach, the main aim of which is to ensure the
conformity of product performance within the specified conditions. As shown in Figure 1, the
aim is now no longer simply to show that the product is in conformity, but to prove that
exploration has been conducted beyond the specified frontier, in order to clean the product of
obstacles limiting its potential robustness, that corresponding to the intrinsic limit set by the
technology.
NOTE It is important to note that performing a highly accelerated test should not lead to over-sizing. The ultimate
purpose of the highly accelerated test is to track down and eliminate extrinsic defects, those which by their very
principle are the result of non-compliance with or ignorance of the state of the art rules of good practice (in design
and manufacture). These actions are therefore dedicated to eliminating extrinsic defects, contributing to improving
the operating margins and obtaining potential margins. Generally speaking, one does not attempt to push back the
fundamental limits of the components and/or materials, which would call into question the design choices (product
and/or processes), entailing significant additional investment and time.

TS 62500 © IEC:2008(E) – 13 –
Stress "j"
Stress "i"
Fundamental
intrinsic limit
Potential
margin
Product
specification area
Combination of
stresses "j+k"
Current domain revealed
by highly accelerated tests Stress "k"
IEC  1265/08
Specified domain: described in the product Technological domain: this corresponds to the

specification. ideal product, designed and produced without
error, but which represents the fundamental
limit, and defines the potential margin with
respect to the specification.
Domain revealed by the highly accelerated tests:

this corresponds to the real limits of the product, Growth in margin by gradually increasing the
as revealed by the highly accelerated tests. The stresses and correcting the extrinsic defects
stars bordering this domain correspond to revealed
extrinsic defects detected, causing the product
to cease to function at this stress level.

Extrinsic defect (to be detected and eliminated)

Figure 1 – Exploration of margins using a highly accelerated test
4.3 Example of the limitations of highly accelerated tests
Despite its efficiency and speed, the highly accelerated test method does, nevertheless, have
its limitations, and these may, in certain cases, require it to be supplemented by prior specific
testing or security checking of product components.
In practice, and independently of the parameters that highly accelerated tests do not address
by their very nature (such as ESDs, sealing, etc.), they provide relatively little information
about the robustness of products that change over time as a result of internal physical-
chemical reactions.
Take, for example, the issue of electromigration in ceramic capacitors:
This effect causes capacitors ultimately to fail as a result of short-circuiting, which may take 2
weeks or 2 years to occur, depending on the design of the product, the manufacturing process
and the conditions under which it is used.

– 14 – TS 62500 © IEC:2008(E)
Highly accelerated testing of a new product cannot always reveal this type of fault, because at
the time of testing, the ceramic capacitor complies fully with its specification and these tests
only marginally accelerate the latent electromigration effect.
In this example, prior “batch reliability” security checking of the capacitors supplied would
considerably reduce the risk involved. Such prior reliability checking could involve specific
humidity/temperature testing of ceramic capacitors, using tests that it may be impossible to
apply to the finished product.
On the basis of this example, it is the feedback of experience that will enable manufacturers
to decide whether the highly accelerated tests they have installed in their development and
mass production processes are sufficient. If not, they should design, evaluate and implement
additional filters to achieve the desired degree of robustness.
5 Industrial technical domains covered by highly accelerated tests
The highly accelerated tests apply to all industrial domains.
From the technical viewpoint, highly accelerated tests are appropriate both to electrical and
electromechanical equipment and to primarily mechanical components.
In the first case, that of electronic or electromechanical systems, they often consist in
applying temperature, vibration and electrical stimuli stresses.
In the second case, the mechanical case, they relate directly to the robustness characteristic
well-known to mechanics and which itself relies on the "safety coefficient" concept. Thus, in a
purely mechanical context, a static highly accelerated test can consist in subjecting a
component or assembly to a rising static stress until, for example, the part deforms or breaks.
A dynamic highly accelerated test can consist in subjecting the component or assembly to
repeated stress cycles (traction/compression cycles, repeated shocks, etc.) to generate
cumulative damage once again leading to deformation or breakage. In this latter case, the
highly accelerated nature can apply to various types of criteria: the stress level, the number of
cycles, the length of the loadings, the combination of stresses, and so on.
In short, highly accelerated tests can apply to all equipment categories, provided that the
most pertinent stresses (mechanical, climatic, electrical, etc.) are used with respect to the
expected failure modes on this equipment.
6 Highly accelerated tests in the lifecycle and associated assembly levels
To ensure optimum efficiency, the highly accelerated tests should be integrated as far
upstream as possible into the product lifecycle, as of the program feasibility phase, at the time
the initial design choices are being made.
During the definition phase, the highly accelerated tests can be implemented on test vehicles
to validate the technological choices and/or processes, and then on the first mock-ups or
prototypes once available, down to basic subassembly level (board, module, etc.), if the level
of testability so allows. The purpose of these first highly accelerated tests is to reveal and
correct the design weaknesses. As the development cycle progresses, more advanced highly
accelerated tests linked to the degree of complexity of the current levels of assembly, are
envisaged. Their goals are: to identify operating margins, to estimate the degree of maturity of
the product and/or its manufacturing processes.
There are four advantages in beginning the highly accelerated tests at a low level of
assembly, as soon as testability makes it possible:
– corrections are easy to make;

TS 62500 © IEC:2008(E) – 15 –
– it is often easier to stimulate low-level assemblies, by applying high stresses, than a
complete system;
– defect monitoring is all the easier, the less complex the level of assembly of the entity
tested;
– it is possible to work on homogeneous technologies.
For each phase in a highly accelerated test, the number of examples under test will depend
on the nature of the highly accelerated tests planned (analysis of a design parameter,
validation of operating margins, identification of inadequacies in the manufacturing processes,
etc.) and on the economic context.
The main goals of the highly accelerated tests at each of the various steps in the lifecycle are
mentioned below.
a) Feasibility
Feasibility corresponds to a technical and industrial analysis with regard to the specified
targets. At this stage, a product design orientation file is produced, and risks are
examined, in order to eliminate unacceptable risks and draw up a plan of action (to be
taken into account as of the definition phase). At this point, the highly accelerated tests to
be performed during the definition phase are scheduled.
b) Definition (preliminary design)
After the feasibility analysis and the preliminary risks have been identified, the highly
accelerated tests help to ratify the product configuration used as the reference for
development launch. When performed on basic sub-assemblies or on an existing product,
they contribute to validating a design mode or a technological choice, to clearing risks
related to the initial design choices, to requesting additional definition work, to proposing
plans of action for the subsequent phases.
c) Development
At the beginning of the development phase, the highly accelerated tests performed on low-
level assembly prototypes enable inadequacies to be highlighted and corrected in terms of
the electrical, mechanical and sometimes software design.
However, when no functional performance is yet measurable, this becomes a limitation of
the highly accelerated tests at this level of assembly. In this case, the highly accelerated
tests process can only be initiated at higher levels of assembly.
As the development phase progresses, other prototypes corresponding to more complex
levels of assembly become available: sets of interconnected boards, unit components in a
system, assembly of mechanical parts, etc. A cycle of highly accelerated tests can be
performed at this level on one or more examples, in order to reveal insufficient operating
margins of the new assemblies thus created. The quantity and nature of these tests also
depend on technological innovations employed and the persistence of the risks, on the
checks needed to prepare for running qualification, control of the series production
resources, and the need for preparing the environmental stress screening profile
applicable to industrialisation and production.
Subject to feasibility, when the first examples of the complete product are available
(component or system), in a configuration representative of the production item, a new
cycle of highly accelerated tests, tailored to this configuration, can again be run, in order
to:
– identify insufficient margins on the interconnections and modules,
– highlight weak points in the manufacturing and assembly processes,
according to the representativeness of the sample of the examples chosen.
Furthermore, the highly accelerated tests facilitate verification and validation stages in the
design cycle.
– 16 – TS 62500 © IEC:2008(E)
d) Qualification and industrialisation
The highly accelerated tests performed during the previous step contribute to the decision
taken during the testability review which determines whether the product is able to
undergo qualification and acts as the starting point for defining the profiles to be applied in
the environmental stress screening or burn-in program. The product configuration is
frozen.
e) Production
During the production phase, periodic highly accelerated tests may be considered on
samples, in order to assess/check variability of processes, procured parts, etc. A process
risk analysis has to be performed previously as a trigger to determine the need of highly
accelerated tests (HAT) during this phase.
f) Commissioning
Not applicable.
g) Operation
In the operation phase,
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