SIST EN IEC 61265:2018
(Main)Electroacoustics - Instruments for measurement of aircraft noise - Performance requirements for systems to measure sound pressure levels in noise certification of aircraft (IEC 61265:2018)
Electroacoustics - Instruments for measurement of aircraft noise - Performance requirements for systems to measure sound pressure levels in noise certification of aircraft (IEC 61265:2018)
This document specifies requirements for the electroacoustical performance of systems of
instruments used to measure sound for the purposes of aircraft noise certification, and for
other comparisons among aircraft models, and provides methods by which tests can be made
periodically to verify that the performance continues to conform to the requirements within
stated limits.
In general, a sound measurement system for this purpose comprises a combination of
instruments extending from a microphone, including its windscreen and other accessories,
through data recording and processing devices to a suitable output. Different measurement
systems, regardless of their composition, perform the necessary functions in different ways
and operate on either analogue or digital principles.
Elektroakustik - Geräte zur Messung des Geräuschs von Luftfahrzeugen - Anforderungen an die Eigenschaften von Systemen zur Messung von Schalldruckpegeln bei der Zertifizierung von Luftfahrzeugen
Électroacoustique - Instruments pour la mesure du bruit des aéronefs - Exigences relatives aux systèmes de mesure des niveaux de pression acoustique pour la certification acoustique des aéronefs
IEC 61265:2018 spécifie les caractéristiques électroacoustiques des systèmes instrumentaux utilisés pour la mesure des bruits dans le cadre de la certification acoustique des aéronefs, ainsi que pour l'établissement d'autres comparaisons entre des modèles d'aéronefs, et fournit des méthodes d'essais de vérification périodique qui permettent de s'assurer du maintien des caractéristiques en conformité avec les exigences, à l'intérieur de tolérances spécifiées.
En général, un système de mesure utilisé à cet effet se compose d'une combinaison d'instruments allant du microphone, y compris son écran anti-vent et ses autres accessoires, en passant par des dispositifs d'enregistrement et de traitement des données, jusqu'à un dispositif de sortie approprié. Les différents systèmes de mesure, indépendamment de leur composition, réalisent les fonctions nécessaires de différentes façons et fonctionnent suivant des principes analogiques ou numériques.
IEC 61265:2018 annule et remplace la première édition parue en 1995. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) ajout de recommandations pour les mesures d'aéronefs autres que des gros avions de transport;
b) ajout de microphones utilisés dans les systèmes de mesure à plan de sol;
c) ajout de mesures de niveau acoustique pondéré, autres que les mesures par bandes de tiers d'octave, pour certains types d'aéronefs;
d) révision et clarification des exigences applicables à l'enregistrement audio numérique;
e) ajout d'exigences pour l'évaluation de l'incertitude de mesure.
Elektroakustika - Instrumenti za merjenje hrupa zrakoplova - Zahteve za delovanje sistemov za merjenje zvočnega tlaka pri certificiranju hrupa zrakoplova (IEC 61265:2018)
Ta dokument določa zahteve za elektroakustično zmogljivost sistemov instrumentov, ki se uporabljajo za merjenje zvoka pri certificiranju hrupa zrakoplova in za druge primerjave med modeli zrakoplovov, ter določa metode, s katerimi je mogoče redno izvajati preskuse, s katerimi se preverja, ali zmogljivost še naprej ustreza zahtevam.
Na splošno sistem za merjenje zvoka za ta namen obsega kombinacijo instrumentov, ki zajema vse od mikrofona, vključno z njegovimi filtri in drugimi dodatki, do naprav za zapisovanje in obdelavo podatkov na ustrezen izhod. Različni merilni sistemi, ne glede na sestavo, opravljajo potrebne funkcije na različne načine in delujejo s pomočjo analognih ali digitalnih načel.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN IEC 61265:2018
01-oktober-2018
1DGRPHãþD
SIST EN 61265:2002
(OHNWURDNXVWLND,QVWUXPHQWL]DPHUMHQMHKUXSD]UDNRSORYD=DKWHYH]DGHORYDQMH
VLVWHPRY]DPHUMHQMH]YRþQHJDWODNDSULFHUWLILFLUDQMXKUXSD]UDNRSORYD ,(&
Electroacoustics - Instruments for measurement of aircraft noise - Performance
requirements for systems to measure sound pressure levels in noise certification of
aircraft (IEC 61265:2018)
Ta slovenski standard je istoveten z: EN IEC 61265:2018
ICS:
17.140.50 Elektroakustika Electroacoustics
49.020 Letala in vesoljska vozila na Aircraft and space vehicles in
splošno general
SIST EN IEC 61265:2018 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN IEC 61265:2018
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SIST EN IEC 61265:2018
EUROPEAN STANDARD EN IEC 61265
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2018
ICS 17.140.50; 49.020 Supersedes EN 61265:1995
English Version
Electroacoustics - Instruments for measurement of aircraft noise
- Performance requirements for systems to measure sound
pressure levels in noise certification of aircraft
(IEC 61265:2018)
Électroacoustique - Instruments pour la mesure du bruit des Elektroakustik - Geräte zur Messung des Geräuschs von
aéronefs - Exigences relatives aux systèmes de mesure Luftfahrzeugen - Anforderungen an die Eigenschaften von
des niveaux de pression acoustique pour la certification Systemen zur Messung von Schalldruckpegeln bei der
acoustique des aéronefs Zertifizierung von Luftfahrzeugen
(IEC 61265:2018) (IEC 61265:2018)
This European Standard was approved by CENELEC on 2018-06-12. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61265:2018 E
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EN IEC 61265:2018
European foreword
The text of document 29/958/CDV, future edition 2 of IEC 61265, prepared by IEC/TC 29
"Electroacoustics" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
EN IEC 61265:2018.
The following dates are fixed:
(dop) 2019-03-12
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2021-06-12
standards conflicting with the
document have to be withdrawn
This document supersedes EN 61265:1995.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Standard IEC 61265:2018 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 61094-4 NOTE Harmonized as EN 61094-4.
IEC 61326-1:2012 NOTE Harmonized as EN 61326-1:2013 (not modified).
IEC 61000-4-2 NOTE Harmonized as EN 61000-4-2.
IEC 61000-4-3 NOTE Harmonized as EN 61000-4-3.
2
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EN IEC 61265:2018
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60942 - Electroacoustics - Sound calibrators EN IEC 60942 -
IEC 61260-1 - Electroacoustics - Octave-band and EN 61260-1 -
fractional-octave-band filters -
Part 1: Specifications
IEC 61672-1 - Electroacoustics - Sound level meters - EN 61672-1 -
Part 1: Specifications
3
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SIST EN IEC 61265:2018
IEC 61265
®
Edition 2.0 2018-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electroacoustics – Instruments for measurement of aircraft noise – Performance
requirements for systems to measure sound pressure levels in noise
certification of aircraft
Électroacoustique – Instruments pour la mesure du bruit des aéronefs –
Exigences relatives aux systèmes de mesure des niveaux de pression
acoustique pour la certification acoustique des aéronefs
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.140.50; 49.020 ISBN 978-2-8322-5695-4
Warning! Make sure that you obtained this publication from an authorized distributor.
Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
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CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Purpose . 11
5 Requirements . 12
5.1 General . 12
5.1.1 Output data . 12
5.1.2 Time-pressure history . 12
5.1.3 Measurements of sound from aircraft ground power units . 12
5.1.4 Measurements of aircraft operations on the ground . 12
5.2 Measurement uncertainty . 12
5.2.1 Relationship with regulatory requirements . 12
5.2.2 Performance verification . 13
5.2.3 Periodic tests . 13
5.3 Reference environmental conditions . 13
5.4 Sound calibrator. 13
5.5 Microphone system . 13
5.5.1 Pressure and free-field type microphones . 13
5.5.2 Grazing incidence microphone configuration . 14
5.5.3 Ground plane microphone configuration . 15
5.5.4 Measurement configurations . 16
5.6 Measurement system exclusive of the microphone . 16
5.6.1 Frequency response . 16
5.6.2 Level linearity . 16
5.6.3 Floating-range measurement systems . 17
5.7 Spectrum analysis system . 17
5.7.1 Third-octave analysis . 17
5.7.2 Time constants . 17
5.7.3 Time offset . 17
5.7.4 Anti-aliasing. 18
5.8 Readout device resolution . 18
5.9 Sensitivity to various environments . 18
5.9.1 General . 18
5.9.2 Atmospheric pressure . 18
5.9.3 Air temperature . 18
5.9.4 Humidity . 19
5.9.5 Electromagnetic compatibility . 19
Annex A (informative) Methods of testing the electroacoustical performance of a
measurement system . 20
A.1 General . 20
A.2 Operating conditions for test . 20
A.3 Sound calibrator. 20
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A.4 Microphone system frequency response . 20
A.5 Frequency response of the measurement system exclusive of the
microphone . 21
A.6 Linear operating range of the measurement system exclusive of the
microphone . 21
A.7 Spectrum analysis system . 21
Annex B (informative) Relationship between tolerance interval, corresponding
acceptance interval and the maximum permitted uncertainty of measurement . 22
Bibliography . 24
Figure 1 – Illustration of sound incidence angles from the principal axis of the
microphone . 15
Figure B.1 – Relationship between tolerance interval, corresponding acceptance
interval and the maximum permitted uncertainty of measurement . 22
Table 1 – ICAO measurement protocols (informative) . 11
Table 2 – Maximum difference between the free-field sensitivity level of a microphone
used in grazing-incidence microphone configuration at normal incidence and at
specified sound incidence angles . 15
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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROACOUSTICS – INSTRUMENTS FOR MEASUREMENT OF
AIRCRAFT NOISE – PERFORMANCE REQUIREMENTS FOR
SYSTEMS TO MEASURE SOUND PRESSURE LEVELS
IN NOISE CERTIFICATION OF AIRCRAFT
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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.
International Standard IEC 61265 has been prepared by IEC technical committee 29:
Electroacoustics.
This second edition cancels and replaces the first edition published in 1995. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) addition of guidance for measurements for aircraft other than large transport aeroplanes;
b) addition of microphones used in ground plane measurement systems;
c) addition of weighted sound level measurements other than one-third-octave band
measurements, for certain aircraft types;
d) revision and clarification of requirements for digital audio recording;
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e) addition of requirements for evaluation of measurement uncertainty.
The text of this International Standard is based on the following documents:
CDV Report on voting
29/958/CDV 29/980A/RVC
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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INTRODUCTION
IEC 61265 provides requirements for the electroacoustical performance of instruments for
measurement of the sound produced by aircraft in flight or on the ground, or by an aircraft
engine installed on an outdoor test stand, for the purposes of demonstrating compliance with
aircraft noise certification limits established by relevant national aviation authorities and for
other comparisons among aircraft models. The instruments can be components of a complete
measurement system. Methods are also indicated by which the performance of such
instruments can be tested periodically.
Measurement and data-analysis procedures for aircraft noise certification are described in
Volume I of Annex 16 to the Convention on International Civil Aviation, with further guidance
and descriptions of acceptable "equivalent procedures" given in the Environmental Technical
Manual prepared by the Committee on Aviation Environmental Protection (CAEP) of the
International Civil Aviation Organization (ICAO). Together these documents are referred to in
this document as "ICAO Annex 16". The procedures include measurement and analysis of the
sound from aircraft in operation, and, in some circumstances, of the sound from static engines
and engines under test, under given operating and atmospheric conditions.
Several of the requirements given in this document differ from the requirements of
IEC 61672-1 for sound level meters, especially concerning the frequency and directional
response, linear operating range and sensitivity to various environments. Many of these
differences are due to the requirement for uniform response at a wide range of angles of
sound arrival as an aircraft moves through the certification test flight. If the output signal from
a measurement system conforming to this document is processed to yield an overall sound
pressure level from all frequency bands, the level derived can differ from that obtained from a
sound level meter conforming to IEC 61672-1.
Systems in accordance with this document are used to perform measurements meeting the
requirements of ICAO Annex 16 or a certifying authority’s specific procedures to demonstrate
that a given aircraft complies with the limits for noise level near the ground over the course of
a test flight. Uncertainty of each measurement is considered when establishing the test
procedures, and it is not the intent of this document to duplicate the confidence interval
analysis inherent in the noise flight test procedure.
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ELECTROACOUSTICS – INSTRUMENTS FOR MEASUREMENT OF
AIRCRAFT NOISE – PERFORMANCE REQUIREMENTS FOR
SYSTEMS TO MEASURE SOUND PRESSURE LEVELS
IN NOISE CERTIFICATION OF AIRCRAFT
1 Scope
This document specifies requirements for the electroacoustical performance of systems of
instruments used to measure sound for the purposes of aircraft noise certification, and for
other comparisons among aircraft models, and provides methods by which tests can be made
periodically to verify that the performance continues to conform to the requirements within
stated limits.
In general, a sound measurement system for this purpose comprises a combination of
instruments extending from a microphone, including its windscreen and other accessories,
through data recording and processing devices to a suitable output. Different measurement
systems, regardless of their composition, perform the necessary functions in different ways
and operate on either analogue or digital principles.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60942, Electroacoustics – Sound calibrators
IEC 61260-1, Electroacoustics – Octave-band and fractional-octave-band filters – Part 1:
Specifications
IEC 61672-1, Electroacoustics – Sound level meters – Part 1: Specifications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
calibration record
time-pressure history or recorded value obtained during a calibration procedure, consisting of
a measurement system output while its acoustic input is provided by a sound calibrator
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3.2
effective perceived noise level
EPNL
EPNdB
single number evaluator of the subjective effects of aircraft noise on human beings,
expressed in decibels (EPNdB) as described in ICAO Annex 16, Appendix I
Note 1 to entry: This note applies to the French language only.
3.3
floating-range measurement system
measurement system incorporating automatic level range switching
3.4
free-field microphone
microphone having substantially uniform frequency response to plane progressive sound
waves arriving at angles substantially normal to the plane of the microphone diaphragm
3.5
free-field sensitivity
quotient of the root-mean-square voltage at the output of a microphone
system by the root-mean-square sound pressure that would exist at the position of the
microphone in the absence of the microphone, for a sinusoidal plane progressive sound wave
of specified frequency, at a specified sound-incidence angle
Note 1 to entry: The free-field sensitivity is expressed in volts per pascal.
3.6
free-field sensitivity level
twenty times the logarithm to the base ten of the ratio of the free-field
sensitivity to the reference sensitivity of one volt per pascal
Note 1 to entry: The free-field sensitivity level is expressed in decibels.
Note 2 to entry: The free-field sensitivity level can be determined by subtracting the sound pressure level (re
20 μPa expressed in dB) of the sound incident on the microphone from the voltage level (re 1 V expressed in dB) at
the output of the microphone system, and adding 93,98 dB to the result.
3.7
grazing incidence
condition where sound from the source of interest impinges on the microphone primarily at an
incidence angle parallel to the plane of the microphone diaphragm
3.8
L
ASmax
maximum value obtained during a given time period or event of A-frequency-weighted, S-time-
weighted sound pressure level
3.9
L
AE
sound exposure level (SEL) of the time integral of squared A-weighted sound pressure over a
given time period or event, with reference to the square of the reference sound pressure of 20
µPa, and a reference duration of one second, as provided by an integrating sound level meter
in accordance with ICAO Annex 16, Appendix 4
Note 1 to entry: L is expressed in decibels.
AE
EXAMPLE L is the sound energy of an acoustic event lasting one second that is equal to the sound energy of
AE
the measured event over the time interval that the A-weighted sound pressure level is within 10 dB of its maximum
value. It is typically 7 dB to 12 dB higher than the L during the same interval.
Amax
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3.10
level difference
measured one-third-octave band output signal level on any level range, adjusted for the
difference between the settings of the level range controls on the level range and the
reference level range, minus the level of the corresponding electrical input signal
Note 1 to entry: The level difference is expressed in decibels.
3.11
level non-linearity
level difference on any level range, at a selected one-third-octave mid-band frequency, minus
the reference level difference, all input and output signals being relative to the same
reference quantity
Note 1 to entry: The level non-linearity is expressed in decibels.
3.12
level range
setting of the controls provided in a measurement system for the recording and level
measurement or spectral analysis of a sound pressure input signal
Note 1 to entry: The level range is expressed in decibels.
3.13
linear operating range
range of levels of steady sinusoidal electrical signals applied to the input of a measurement
system exclusive of the microphone system, extending from a lower boundary to an upper
boundary, over which the level non-linearity is within limits specified in 5.6.2
Note 1 to entry: The linear operating range applies to a stated level range and is expressed in decibels.
3.14
measurement system
combination of instruments used for the measurement of sound pressure levels, including a
sound calibrator, microphone system, signal recording and conditioning devices, and one third
octave band spectrum analysis or A-frequency-weighted, S-time-weighted sound level
measurement as required for the aircraft type being evaluated
Note 1 to entry: The measurement system covered by this document does not include analysis means for
computing metrics such as EPNL (EPNdB) or SEL (L ).
AE
Note 2 to entry: Practical installations can include a number of microphone systems, the outputs from which are
recorded simultaneously by a multi-channel recording device. The signal recording and conditioning devices and/or
the spectrum analysis system can have separate channels in parallel, again with facilities for selection, either of
the input or of the output. For the purposes of this document, each combination of a single microphone system and
a single data-recording and data-analysis channel within the other instruments comprises a separate, complete
measurement system, and the requirements apply accordingly.
3.15
microphone
electroacoustic transducer converting audio-frequency air pressure variations to AC voltage
Note 1 to entry: Microphones used for aircraft noise certification are typically of the electrostatic or "condenser"
type which have an output impedance requiring a preamplifier to be located adjacent to the microphone rather than
in external equipment connected to the microphone by a cable.
3.16
micro
...
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