IEC PAS 62500:2006

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IEC
AVAILABLE
PAS 62500
SPECIFICATION
First edition
Pre-Standard
2006-11
Process management for avionics –

Guide for defining and performing highly
accelerated tests in avionic systems

Reference number
IEC/PAS 62500:2006(E)
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PUBLICLY
IEC
AVAILABLE
PAS 62500
SPECIFICATION
First edition
Pre-Standard
2006-11
Process management for avionics –

Guide for defining and performing highly
accelerated tests in avionic systems

IEC 2006   Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
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V
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – IEC/PAS 62500 © IEC 2006

CONTENTS
FOREWORD.3

1 Scope and object.4

2 Terms and definitions .5

3 Acronyms .7

4 Highly accelerated test goals and principles .7

4.1 General characteristics .7
4.2 General principles of highly accelerated tests.8
4.3 Example of the limitations of highly accelerated tests .10
5 Industrial technical domains covered by highly accelerated tests .11
6 Highly accelerated tests in the life cycle and associated assembly levels.11
7 Planning and management of highly accelerated tests.13
7.1 Validation and verification.13
7.2 Planning of highly accelerated tests .14
7.3 Management of highly accelerated tests.15
8 General methodology for implementing highly accelerated tests .15
8.1 Structure of the approach .15
8.2 Analysis of product sensitive points.16
8.3 Selection of applicable stresses .17
8.4 Producing a test plan.18
8.5 Tests performing .20
8.6 Analysis of test results, corrective action and resumption of testing .21
9 Building on and using experience.21
9.1 Creating the database .22
9.2 Inclusion in the company reference system .22
9.3 Use of results for environmental stress screening.22
9.4 Correlation with feedback .23
9.5 Synthesis and impact on company culture .23
10 Customer/supplier relations .23
10.1 Prime contractor/supplier relations .23
10.2 Supplier/test laboratory relations.24

11 Profitability of highly accelerated tests .25
11.1 General .25
11.2 "Non-reliability" costs.26
11.3 Expenses generated by the highly accelerated tests.28
Annex A (informative) Comparative characteristics of highly accelerated tests and
reliability tests .30
Annex B (informative) Example of potential effectiveness table for stresses or loadings
according to the nature of the product sensitive point .31
Annex C (informative) Highly accelerated tests implementation logic.32
Annex D (informative) Margin-related statistical considerations for telecommunications
circuit-boards or board assembly .34
Bibliography .35

IEC/PAS 62500 © IEC 2006 – 3 –

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
PROCESS MANAGEMENT FOR AVIONICS –

Guide for defining and performing highly accelerated tests

in avionic systems
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
A PAS is a technical specification not fulfilling the requirements for a standard but made
available to the public.
IEC-PAS 62500 has been prepared by IEC technical committee 107: Process management for
avionics.
The text of this PAS is based on the This PAS was approved for publication
following document: by the P-members of the committee
concerned as indicated in the following
document:
Draft PAS Report on voting
107/54/NP 107/61/RVN
Following publication of this PAS, which is a pre-standard publication, the technical committee
or subcommittee concerned will transform it into an International Standard.
This PAS shall remain valid for an initial maximum period of three years starting from 2006-11.
The validity may be extended for a single three-year period, following which it shall be revised
to become another type of normative document or shall be withdrawn.

– 4 – IEC/PAS 62500 © IEC 2006

PROCESS MANAGEMENT FOR AVIONICS –

Guide for defining and performing highly accelerated tests

in avionic systems
1 Scope and object
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, we on the contrary attempt 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 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.
)
The object of this PAS is to specify the targets assigned to the highly accelerated tests,
their basic principle, their scope of application and their implementation procedures.
This guide is thus a methodological document aimed at facilitating drafting of the specification
and then performance of highly accelerated tests by the programme managers.
It is primarily intended for programme managers, designers, test managers, and RAMS
experts.
This guide concerns all programmes, in particular aeronautical, space and armaments
programmes. It primarily concerns the industrial firms in charge of designing, developing and

producing components built for these programmes, but also their customers who, in drafting
contractual clauses, may require that their suppliers implement highly accelerated tests.
The recommendation 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 components or component groups.
NOTE Presently, there are no documentary standards for highly accelerated tests. This recommendation thus
relies on a number of documents which are not standards, which are of various origins and which are usually very
recent, as well as on other more standard documents, but not specifically dedicated to highly accelerated tests.
______________
)
Proposed by a working group comprising representatives of the aeronautical, space and armaments industries
(customers and suppliers), as well as representatives of laboratories specialising in testing.

IEC/PAS 62500 © IEC 2006 – 5 –

2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

NOTE Most of the terminology used in this recommendation 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
chargeable 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 resistance limit imposed by the technologies used.
2.5
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
2.6
patent defect
defect in a component which, after being precipitated, has become detectable by conventional
performance checks. A patent defect thus stems from a latent defect which has evolved
following application of appropriate stresses (for example, temperature, vibrations, etc.) and
which thus becomes detectable by a performance check.

2.7
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 defects which, in all
probability, would have appeared once utilization had begun (teething troubles)
2.8
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. Contrary to highly accelerated testing, a "conventional" accelerated test
(time/stress exchange) always relies on one or more analytical lifetime and damage models

– 6 – IEC/PAS 62500 © IEC 2006

2.9
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 PAS.

2.10
reliability
ability of a product to perform a required function, in given conditions, for a given time interval,
generally expressed by a probability
2.11
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)
2.12
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)
2.13
fundamental limit
resistance 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 chargeable
defect
NOTE Examples are the melting temperature of a plastic, the maximum junction temperature of a semiconductor,
the yield strength of a material, etc.
2.14
operating margin
for a given stress, difference between the operating limit and the specification
2.15
destruct margin
for a given stress, difference between the destruct limit and the specification

2.16
maturity
attainment of a product status for which its functional and operational performance can be
considered stabilized with respect to the specifications
NOTE Maturity is the result of a gradual process of eliminating chargeable defects still present in the product
and the associated processes. This process is called maturing.
2.17
precipitation
transformation, using appropriate stresses, of a latent defect (not yet detectable) into a patent
defect (detectable)
IEC/PAS 62500 © IEC 2006 – 7 –

2.18
robustness
property of a product indicating reduced sensitivity of its performance to changes in the

environmental stresses to which it is subjected, to dispersions of its components and to drifts

of its manufacturing processes. 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

2.19
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

3 Acronyms
• CDR Critical Design Review.
• EMC Electromagnetic Compatibility.
• ESS Environmental Stress Screening.
• FMECA Failure Mode Effects and Criticality Analysis.
• FRACAS Failure Reporting and Corrective Action System.
• MTBF Mean Time Between Failures.
• PCB: Printed Circuit Board.
• PDR: Preliminary Design Review.
• PRA Preliminary Risk Analysis.
• 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;
– 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 chargeable 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;
– 8 – IEC/PAS 62500 © IEC 2006

– exploration of the operating limits, once chargeable 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, we will on the contrary look 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 chargeable

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: we here understand that a highly
accelerated test shall 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 evolution. The
highly accelerated test is "proactive" in that it encourages these engineering actions at the
earliest 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 at ensuring that the
product's performance is correct when it is subjected to the specific operating and
environmental conditions.
– A highly accelerated test must 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 must 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 has no predictive goal: 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

IEC/PAS 62500 © IEC 2006 – 9 –

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 resistance 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 (chargeable
defects). An essential goal of the highly accelerated test is precisely to reveal the existence of

these chargeable 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 chargeable defects which only trigger
malfunctions in out-of-specification product operating conditions, we could mention the
following.
– 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
chargeable 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 chargeable defects can often be easily located and can be
eliminated or attenuated both easily and economically (for example, 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 in 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 correspond to the resistance 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 chargeable 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 chargeable 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.

– 10 – IEC/PAS 62500 © IEC 2006

Stress "i"
Stress "j"
Fundamental
Potential
resistance limit
margin
Combination
of stresses "j+k"
Current domain
revealed by highly
accelerated tests
Specified domain: described in the product  Technological domain: this corresponds to

specification. the 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 Growth in margin by gradually increasing
the product, as revealed by the highly the stresses and correcting the chargeable
accelerated tests. The stars bordering this defects revealed

domain correspond to chargeable defects
Chargeable defect (to be detected and
detected, causing the product to cease to
eliminated)
function at this stress level.

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 physico-
chemical reactions.
Take, for example, the issue of electromigration in ceramic condensers.
This effect causes condensers ultimately to fail as a result of short-circuiting, which may take
two weeks or two years to occur, depending on the design of the product, the manufacturing
process and the conditions under which it is used.

IEC/PAS 62500 © IEC 2006 – 11 –

Highly accelerated testing of a new product cannot always reveal this type of fault, because at

the time of testing, the ceramic condenser 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 condensers supplied would

considerably reduce the risk involved. Such prior reliability checking could involve specific

humidity/temperature testing of ceramic condensers, 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 must 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 life cycle and associated assembly levels

To ensure optimum efficiency, the highly accelerated tests must be integrated as far upstream
as possible into the product life cycle, as of the programme 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 and to estimate the degree of
maturity of the product and/or its manufacturing processes.
The following are the four advantages in beginning the highly accelerated tests at a low level
of assembly, as soon as testability makes it possible.

– 12 – IEC/PAS 62500 © IEC 2006

– Corrections are easy to make.

– 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 subassemblies 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 industrialization 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; and
– 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 the verification and validation stage in
the design cycle.
IEC/PAS 62500 © IEC 2006 – 13 –

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 programme. The product configuration is

frozen and no corrective action must be taken.

e) Production
During the production phase, periodic highly accelerated tests may be envisaged on

samples, in order to ensure that there is no drift in the functional margins identified
following the development phase. They represent a pertinent indicator for maintaining

production quality, as well as an effective tool for taking account of corrective action

(processes, procurements, checks, etc.).
f) Commissioning
Not applicable.
g) Operation
In the operation phase, highly accelerated tests may be used during investigations into
confirmed or revealed drifts (modification of certain components, change in suppliers, etc.)
through experience feedback or during evolution of design.
7 Planning and management of highly accelerated tests
The highly accelerated tests constitute both a major development activity, facilitating in
particular the verification and validation stages, in the same way as the qualification tests,
and an activity involving many programme representatives (design, industrialization,
production) whose work must be harmonized by a coordinator, guaranteeing correct
performance of the tests and their successful completion, as well as a demanding activity in
terms of human resources, equipment and tests.
In this respect, and in the same way as the qualification tests, this activity shall be planned in
the upstream phases of the programme and shall then be closely monitored during
implementation.
The aim of this paragraph is to state, independently of the techniques employed and as
described in the next chapter, the steps that should be taken when planning the tests and
when performing them.
In addition, setting up a highly accelerated tests procedure is one of the steps taken to deal
with the risk of belated product maturity and lack of robustness. The aims of the approach are
set in the light of these risks, at the same time as the requirements concerning the product.

The level of residual risk after performance of the highly accelerated tests shall therefore be
analysed, as should the stresses linked to this approach.
7.1 Validation and verification
Highly accelerated tests are central to the validation of specifications and the verification of
final products.
The objectives of this approach are
– to ensure that the requirements imposed by technical specifications will meet the needs of
the final user (validation);
– to ensure that the intermediate products and final product will comply with their
specifications, particularly those concerned with maturity and robustness (verification).

– 14 – IEC/PAS 62500 © IEC 2006

To achieve these two objectives, the validation and verification approach requires the

implementation of key activities, such as

– accepting the requirements imposed by technical specifications and validating the user

needs and constraints supplied by the customer;

– validating the hypotheses on which product specifications are based, i.e. the assurance

that the specifications are sufficiently appropriate, correct and complete that the final

product will comply with the explicit and implicit needs of users;

– verifying that intermediate products and the final product comply with their individual

specifications.
Highly accelerated tests use the results obtained from the first two activities as preliminary
product risk analyses and form an integral part of validation and verification.
7.2 Planning of highly accelerated tests
When planning the programme
...