IEC TS 62500:2008
(Main)Process management for avionics - Defining and performing highly accelerated tests in aerospace systems - Application guide
Process management for avionics - Defining and performing highly accelerated tests in aerospace systems - Application guide
IEC/TS 62500:2008(E) specifies the targets assigned to highly accelerated tests, their basic principles, their scope of application and their implementation procedures. 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. 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.
General Information
Standards Content (sample)
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)
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2008 IEC, Geneva, Switzerland
All rights reserved. Unless otherwise specified, 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 either IEC or
IEC's member National Committee in the country of the requester.If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,
please contact the address below or your local IEC member National Committee for further information.
IEC Central Office3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
Web: www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.ƒ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.ƒ IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.ƒ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.ƒ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:Email: csc@iec.ch
Tel.: +41 22 919 02 11
Fax: +41 22 919 03 00
---------------------- Page: 2 ----------------------
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
ICS 03.100.50; 31.020; 49.060 ISBN 2-8318-9933-8
® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 3 ----------------------
– 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
---------------------- Page: 4 ----------------------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
---------------------- Page: 5 ----------------------– 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
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
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
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.---------------------- Page: 6 ----------------------
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.
---------------------- Page: 7 ----------------------
– 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.---------------------- Page: 8 ----------------------
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 repair2.3
soft failure
failure appearing after a certain given stress level, which disappears when the stress falls
back below this level2.4
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 marginsNOTE 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---------------------- Page: 9 ----------------------
– 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 equipment2.7
patent defect
defect in a component which, after being precipitated, has become detectable by conventional
performance checksNOTE 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.
2.8environmental 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)
2.9accelerated 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 profileNOTE 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 productNOTE 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.
2.11reliability
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)
---------------------- Page: 10 ----------------------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 specificationsNOTE 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 processesNOTE 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
2.21failure 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 item3 Acronyms
• CDR: Critical Design Review.
• FMEA: Failure Modes and Effects Analysis.
• EMC: Electromagnetic Compatibility.
• ESS: Environmental Stress Screening.
---------------------- Page: 11 ----------------------
– 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 beeconomically feasible and which will enable them to be eliminated or at least delay their
---------------------- Page: 12 ----------------------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 thespecifications. 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...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.