1、BRITISH STANDARDBS EN 4533-003:2006Aerospace series Fibre optic systems Handbook Part 003: Looming and installation practicesThe European Standard EN 4533-003:2006 has the status of a British StandardICS 49.060g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g
2、50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 4533-003:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2006 BSI 2006ISBN 0 580 49445 4National forewordThis B
3、ritish Standard was published by BSI. It is the UK implementation of EN 4533-003:2006. The UK participation in its preparation was entrusted by Technical Committee ACE/6, Aerospace avionic electrical and fibre optic technology, to Subcommittee ACE/6/-/10, Aerospace Fibre optic systems and equipment.
4、A list of organizations represented on ACE/6/-/10 can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from lega
5、l obligations.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 4533-003July 2006ICS 49.060English VersionAerospace series - Fibre optic systems - Handbook - Part 003:Looming and installation practicesSrie arospatiale - Systmes des fibres opti
6、ques - Manueldutilisation - Partie 003 : Rgles de lart pour la fabricationet linstallation des harnaisLuft- und Raumfahrt - Faseroptische Systemtechnik -Handbuch - Teil 003: Praktiken zur Fertigung undInstallation von LeitungsbndelnThis European Standard was approved by CEN on 28 April 2006.CEN memb
7、ers are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application
8、 to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same
9、status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia
10、, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reservedworldwide for CE
11、N national Members.Ref. No. EN 4533-003:2006: E2 Contents Page Foreword3 Introduction .4 1 Scope 5 2 Normative references 5 3 Initial design considerations 5 3.1 General5 3.2 System design considerations.6 3.2.1 Connectorisation and available power budget.6 3.2.2 The use of redundancy .7 3.2.3 Spare
12、 cabling .7 3.2.4 Dormant fibres .7 3.3 Harness routing considerations.8 3.3.1 General8 3.3.2 Drip loops .8 3.3.3 Circular paths.9 3.4 Securing and attachment mechanisms.9 3.5 Protection mechanisms . 11 3.5.1 General. 11 3.5.2 Conduit 11 3.6 Installation mechanisms 13 3.7 Through life support. 13 4
13、Manufacturing issues. 15 4.1 General. 15 4.2 Handling. 15 4.2.1 General. 15 4.2.2 Minimum bend radii 15 4.2.3 Forming the loom 16 4.3 Cable identification methods. 16 4.3.1 Identifications 16 4.3.2 Heatshrink identification sleeves 16 4.4 Installation of fibres in conduit . 17 4.4.1 General. 17 4.4.
14、2 Connectors and conduit 17 5 Looming and installation on aircraft. 17 5.1 Termination, protection of the end-face. 17 5.1.1 General. 17 5.1.2 Free connectors 18 5.1.3 Fixed connectors 18 5.2 Pulling of fibre optic cables/harnesses through conduits during installation. 19 5.3 Routing of fibre optic
15、cables through pressure bulkheads . 19 5.4 Electrical/optical . 19 5.5 Additional considerations 19 5.5.1 Cable marking . 19 5.5.2 Cable storage 20 EN 4533-003:20063 Foreword This European Standard (EN 4533-003:2006) has been prepared by the European Association of Aerospace Manufacturers - Standard
16、ization (AECMA-STAN). After enquiries and votes carried out in accordance with the rules of this Association, this Standard has received the approval of the National Associations and the Official Services of the member countries of AECMA, prior to its presentation to CEN. This European Standard shal
17、l be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January 2007, and conflicting national standards shall be withdrawn at the latest by January 2007. Attention is drawn to the possibility that some of the elements of this docu
18、ment may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard:
19、Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 4533-003:200
20、64 Introduction a) The handbook The handbook draws on the work of the Fibre-Optic Harness Study, part sponsored by the United Kingdoms Department of Trade and Industry, plus other relevant sources. It aims to provide general guidance for experts and non-experts alike in the area of designing, instal
21、ling, and supporting multi-mode 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:
22、 Test and measurement Part 003: Looming and installation practices Part 004: Repair, maintenance and inspection b) Background It is widely accepted in the aerospace industry that photonic technology offers a number of significant advantages over conventional electrical hardware. These include massiv
23、e signal bandwidth capacity, electrical safety, and immunity of passive fibre-optic components to the problems associated with electromagnetic interference (EMI). To date, the latter has been the critical driver for airborne fibre-optic communications systems because of the growing use of non-metall
24、ic 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
25、in many avionic applications, such as video/sensor multiplexing, flight control signalling, electronic warfare, and entertainment systems, as well as in sensing many of the physical phenomena on-board aircraft. The basic optical interconnect fabric or optical harness is the key enabler for the succe
26、ssful 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, vibrations, and contamination) and accommodate additi
27、onal 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 in
28、ternational 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 le
29、ss competitive than an electrical equivalent. c) The fibre-optic harness study The Fibre-Optic Harness Study concentrated on developing techniques, guidelines, and standards associated with the through-life support of current generation fibre-optic harnesses applied in civil and military airframes (
30、fixed and rotary wing). Some aspects of optical system design were also investigated. This programme has been largely successful. Guidelines and standards based primarily on harness study work are beginning to emerge through a number of standards bodies. Because of the aspects covered in the handboo
31、k, European prime contractors are in a much better position to utilise and support available fibre optic technology. EN 4533-003:20065 1 Scope Looming and installation practices are a critical aspect of any aircraft electrical/avionics installation. In order to provide a reliable and efficient syste
32、m it is important that the harness installation is designed for reliability and maintainability. This concept holds true for both copper based and fibre optic harnesses. The objective of this part of EN 4533 is to provide technical advice and assistance to designers and engineers on the incorporatio
33、n of fibre optic harnesses into an airframe, while maintaining maximum compliance with current aircraft electrical harness procedures. This part considers the looming and installation aspects during initial design, throughout the manufacture and installation of the fibre optic harness and how the pr
34、actices chosen affect through life support of the harness. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (in
35、cluding any amendments) applies. EN 4533-001, Aerospace series Fibre optic systems Handbook Part 001: Termination methods and tools. 3 Initial design considerations 3.1 General The installation of fibre optic harnesses should aim to mirror that of copper systems and comply as much as possible with c
36、urrent 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) A
37、ccessibility for inspection and maintenance; b) Prevent or minimise 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
38、, mud and burst tyre debris in landing gear bays; Combat damage (to the maximum extent practicable); Loose or moving parts; Moisture and fluids; Localised high temperatures; Frequent mating and de-mating of connectors; Exposure to high temperature/high vibration areas. EN 4533-003:20066 Copper insta
39、llations are prone to electrical interference and their use is restricted in “volatile” zones. Fibre optic cables are virtually 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
40、solution over copper include: c) Areas where there are high levels of electrical, field strength; 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) an
41、d 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 protecti
42、on; i) System segregation and redundancy, maximisation of damage limitation; j) Accessibility of connectors; k) System and component repair and maintenance issues; l) Introduction of dormant fibre in harnesses and/or extra fibre lengths may reduce on-aircraft repair times. 3.2 System design consider
43、ations 3.2.1 Connectorisation and available power budget Careful attention should be made to the number and placement of connectors in the optical harness. The final choice and location of connectors needs to consider the required performance, reliability and maintenance aspects of the system. These
44、 aspects often conflict with each other in system design and so some trade-off should be performed at the design stage. Of primary importance is that the harness components do not introduce a loss that exceeds the power budget of the system. Provided that sufficient power budget is available, the us
45、e of appropriately positioned connector breaks can improve the maintainability of the system. For example, in areas of high maintenance activity where there is an increased likelihood of damage, the use of additional connector breaks will facilitate a quick and simple replacement of damaged cable. T
46、his in turn has to be traded off against the possibility that the additional connectors may themselves fail, reducing the reliability of the system. Experience has shown that failures at or near to the connector are not an uncommon failure mode, particularly where loads placed on the harness are eas
47、ily transferred to the connector backshell. Careful placement of the connector and the use of appropriate harness tie-down mechanisms will reduce the likelihood of this type of failure. In summary the introduction of additional connectors should be considered if the loss increase induced by the intr
48、oduction is within the power budget of the system, and the additional connectors improve maintainability without causing impact on the reliability of the system. EN 4533-003:20067 3.2.2 The use of redundancy Redundancy can be utilised in a fibre optic application without excessively diminishing the
49、weight savings attained by using fibre optic cable. However, the introduction of additional cables will inevitably increase initial cost and system complexity, together with the additional problems of cable end/ferrule protection and stowage. In addition, any spare or redundant fibres would be subject to the same or similar environmental conditions as the live fibre it is duplicating. Clearly, the more in-built redundancy the increased survivability of the system. Deciding on the level of redundancy and depth required, shoul
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