prEN 4533-003

SLOVENSKI STANDARD
01-junij-2024
Aeronavtika - Sistemi iz optičnih vlaken - Priročnik - 003. del: Postopki za izdelavo
in namestitev vezalnega pasovja
Aerospace series - Fibre optic systems - Handbook - Part 003: Looming and installation
practices
Luft- und Raumfahrt - Faseroptische Systeme - Handbuch - Teil 003: Verfahren zur
Fertigung und Installation von Leitungsbündeln
Série aérospatiale - Systèmes des fibres optiques - Manuel d’utilisation - Partie 003 :
Règles de l’art pour la fabrication et l’installation des harnais
Ta slovenski standard je istoveten z: prEN 4533-003
ICS:
33.180.01 Sistemi z optičnimi vlakni na Fibre optic systems in
splošno general
49.060 Letalska in vesoljska Aerospace electric
električna oprema in sistemi equipment and systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2024
ICS 49.060 Will supersede EN 4533-003:2017
English Version
Aerospace series - Fibre optic systems - Handbook - Part
003: Looming and installation practices
Série aérospatiale - Systèmes des fibres optiques - Luft- und Raumfahrt - Faseroptische Systeme -
Manuel d'utilisation - Partie 003 : Règles de l'art pour Handbuch - Teil 003: Verfahren zur Fertigung und
la fabrication et l'installation des harnais Installation von Leitungsbündeln
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee ASD-
STAN.
If this draft becomes a European Standard, CEN 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.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 4533-003:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Initial design considerations . 5
4.1 General. 5
4.2 System design considerations . 6
4.2.1 Introduction . 6
4.2.2 Interconnects . 7
4.2.3 Maintainability strategy . 8
4.3 Practical harness routing considerations . 9
4.4 Securing and attachment mechanisms . 9
4.5 Protection mechanisms . 12
4.5.1 General. 12
4.5.2 Conduit. 12
4.6 Installation mechanisms . 14
4.7 Through life support . 15
4.8 Enabling fibre optic cable re-termination . 15
4.9 Handling . 17
Bibliography . 18
European foreword
This document (prEN 4533-003:2024) has been prepared by ASD-STAN.
After enquiries and votes carried out in accordance with the rules of this Association, this document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 4533-003:2017.
The main changes with respect to the previous edition are as follows:
— update of the document to remove trademarks.
Introduction
a) The handbook
This handbook aims to provide general guidance for experts and non-experts alike in the area of
designing, installing, and supporting fibre-optic systems on aircraft. Where appropriate more detailed
sources of information are referenced throughout the text.
It is arranged in 4 parts, which reflect key aspects of an optical harness life cycle, namely:
— Part 001: Termination methods and tools;
— Part 002: Test and measurement;
— Part 003: Looming and installation practices;
— Part 004: Repair, maintenance, cleaning and inspection.
b) Background
It is widely accepted in the aerospace industry that photonic technology significant advantages over
conventional electrical hardware. These include massive signal bandwidth capacity, electrical safety,
and immunity of passive fibre-optic components to the problems associated with electromagnetic
interference (EMI). Significant weight savings can also be realized in comparison to electrical harnesses
which may require heavy screening. To date, the EMI issue has been the critical driver for airborne
fibre-optic communications systems because of the growing use of non-metallic aerostructures.
However, future avionic requirements are driving bandwidth specifications from 10s of Mbits/s into the
multi-Gbits/s regime in some cases, i.e. beyond the limits of electrical interconnect technology. The
properties of photonic technology can potentially be exploited to advantage in many avionic
applications, such as video/sensor multiplexing, flight control signalling, electronic warfare, and
entertainment systems, as well as sensor for monitoring aerostructure.
The basic optical interconnect fabric or ‘optical harness’ is the key enabler for the successful
introduction of optical technology onto commercial and military aircraft. Compared to the mature
telecommunications applications, an aircraft fibre-optic system needs to operate in a hostile
environment (e.g. temperature extremes, humidity, vibration, and contamination) and accommodate
additional physical restrictions imposed by the airframe (e.g. harness attachments, tight bend radii
requirements, and bulkhead connections). Until recently, optical harnessing technology and associated
practices were insufficiently developed to be applied without large safety margins. In addition, the
international standards did not adequately cover many aspects of the life cycle. The lack of accepted
standards thus lead to airframe specific hardware and support. These factors collectively carried a
significant cost penalty (procurement and through-life costs), that often made an optical harness less
competitive than an electrical equivalent. This situation is changing with the adoption of more
standardized (telecoms type) fibre types in aerospace cables and the availability of more ruggedized
COTS components. These improved developments have been possible due to significant research
collaboration between component and equipment manufacturers as well as the end use airframers.
1 Scope
This handbook considers the best practices during initial design and how the practices chosen affect
through life support of the installation. Looming and installation practices are a critical aspect of any
aircraft electrical/avionics installation. In order to provide a reliable and efficient system, it is
important that the fibre optic installation is designed for reliability and maintainability.
This document provides technical advice and assistance to designers and engineers on the
incorporation of fibre optic harnesses into an airframe, while, wherever possible, maintaining
maximum compliance with current aircraft electrical harness procedures.
All topics that are related to the installation of optical cables are addressed in EN 3197.
These rules are applicable for fibre optic cables and connectors defined by EN specifications.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
4 Initial design considerations
4.1 General
Wherever possible the installation of fibre optic links and bundles should aim to mirror that of copper
systems and comply as much as possible with current general aircraft electrical harness procedures.
There are numerous installation specifications detailing the requirements for the routing of copper-
based harnesses, however they are very similar in content, therefore fibre optic harness routing will
have to fulfil the following criteria:
a) accessibility for inspection and maintenance;
b) prevent or minimize the risk of damage from:
— chafing, scraping or abrasion,
— use as handholds or as support for personal equipment,
— damage by personnel moving within the aircraft,
— stowage or movement of cargo,
— battery electrolytes and fumes,
— stones, ice, mud and burst tyre debris in landing gear bays,
— combat damage (to the maximum extent practicable),
— loose or moving parts,
— moisture and fluids,
— localized high temperatures,
— frequent mating and de-mating of connectors,
— exposure to high temperature/high vibration areas.
Copper installations are prone to electrical interference and their use is restricted in “volatile” zones.
Fibre optic cables are immune to electrical interference and are ideally suited for use in, or routing
through “volatile” zones. Examples of areas that fibre optic harnesses may provide a better solution
over copper include:
c) areas where there are high levels of electrical field;
d) areas where electric fields need to be kept to a minimum, e.g. compass deviation;
e) routing through and close to fuel tanks;
f) close proximity to electrically initiated explosive devices (EIEDs) and their systems.
During the design phase of a fibre optic installation routing considerations need to be addressed when
determining the optimum routing, these include:
g) system criticality;
h) harness accessibility, improves on-aircraft repair and maintenance, but should not degrade system
protection;
i) system segregation and redundancy, maximization of damage limitation;
j) accessibility of connectors;
k) system and component repair and maintenance issues (it is noted that design of common harness
lengths on an aircraft may improve the supportability (common spares inventory) if repairs are
required);
l) introduction of dormant fibre in harnesses and/or extra fibre lengths may reduce on-aircraft repair
times.
4.2 System design considerations
4.2.1 Introduction
In the design of a fibre optic harness, the link topology and the available routing path on the platform
will dictate the physical length of the harness and any requ
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