Bsi bs en 04660 004 2011

BS EN 4660-004:2011 BSI Standards Publication Aerospace series — Modular and Open Avionics Architectures Part 004: Packaging NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW raising standards worldwide™ BS EN 4660-004:2011 BRITISH STANDARD National foreword This British Standard is the UK implementation of EN 4660-004:2011 The UK participation in its preparation was entrusted to Technical Committee ACE/6, Aerospace avionic electrical and fibre optic technology A list of organizations represented on this committee 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 © BSI 2011 ISBN 978 580 62444 ICS 49.090 Compliance with a British Standard cannot confer immunity from legal obligations This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2011 Amendments issued since publication Date Text affected BS EN 4660-004:2011 EN 4660-004 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM February 2011 ICS 49.090 English Version Aerospace series - Modular and Open Avionics Architectures Part 004: Packaging Série aérospatiale - Architectures Avioniques Modulaires et Ouvertes - Partie 004: Packaging Luft- und Raumfahrt - Modulare und offene Avionikarchitekturen - Teil 004: Packaging This European Standard was approved by CEN on 26 June 2010 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 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 CEN 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 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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels © 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Ref No EN 4660-004:2011: E BS EN 4660-004:2011 EN 4660-004:2011 (E) Contents Page Foreword 4 0 Introduction 5 0.1 Purpose 5 0.2 Document structure 6 1 Scope 6 2 Normative references 7 3 3.1 3.2 3.3 3.4 Terms, definitions and abbreviations 8 Terms and definitions 8 Abbreviations 8 Precedence 9 Definition of terms 9 4 4.1 4.2 4.3 4.4 4.5 4.6 Generic module specification 11 Introduction 11 Module description 12 Module Physical Specification 12 Module Physical Interface - Connector 16 Module Physical Interface - Cooling 20 Module Physical Interface – Insertion Extraction Device 23 5 5.1 5.2 Module Mechanical Tests 25 Master gauge test 25 Module insertion and extraction 25 6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Guidelines for a rack slot 27 Introduction 27 Interchangeability 27 Rack Slot Design Requirements 27 Connector interface 28 Conduction Cooled Interface 29 Air Flow Cooled Interface 30 Relationship between Cooling, Connector and IED Rack Interfaces 32 7 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 7.10 7.11 7.12 7.13 7.14 7.15 7.16 7.17 7.18 7.19 Typical modular avionics environment 33 Ambient pressure (altitude) 34 Humidity 34 High and low temperatures 34 Thermal shocks 35 Salt spray 36 Vibrations 36 Accelerations 37 Mechanical shocks 38 Contamination resistance 39 Flame resistance 39 Fungus resistance 39 Rain 39 Acoustic noise 40 Electromagnetic environment 40 Explosive atmosphere 40 Nuclear, Biological and Chemical (NBC) Hazards 40 Sand and dust 42 Single Event Upset / Multiple Bit Upset 42 Module Tempest 42 BS EN 4660-004:2011 EN 4660-004:2011 (E) Figures Page Figure — ASAAC Standard Documentation Hierarchy .5 Figure — Module definitions 10 Figure — CFM dimensions 13 Figure — Module Connector Interface Definition and Identification (connector inserts shown for example only) 16 Figure — Preferred Contact Identification (viewed from outside module, lowest numbered contact is towards Side C of the cassette) 17 Figure — Contact Identification – MT Ferrule .18 Figure — Polarisation Key identification 19 Figure — Conduction Cooled Module – Cooling Interface Definition 20 Figure — Air cooled module – Cooling interface definition 22 Figure 10 — IED Hook characteristics 24 Figure 11 — IED Implementation example .25 Figure 12 — Rack Connector Physical Interface 28 Figure 13 — Conduction Cooled rack guide rail 29 Figure 14 — Air Flow Through and Direct Air Flow cooled rack guide rail 30 Figure 15 — Air Flow Around cooled rack guide rail 31 Tables Page Table — Allowed aluminium protective treatments 14 Table — Ambient pressure in relation to altitude 34 Table — Temperature environmental conditions - Conditioned bay .35 Table — Temperature environmental conditions - Unconditioned bay 35 Table — Temperature environmental conditions - Storage 35 Table — Thermal shocks 36 Table — Sinusoidal vibrations .36 Table — Rotational accelerations 37 Table — Transversal accelerations .38 Table 10 — Functional Shocks 38 Table 11 — Summary of environment and bonding environmental Conditions 40 Table 12 — Initial Nuclear radiation conditions 41 Table 13 — Nuclear hardening conditions .41 BS EN 4660-004:2011 EN 4660-004:2011 (E) Foreword This document (EN 4660-004:2011) has been prepared by the Aerospace and Defence Industries Association of Europe - Standardization (ASD-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 ASD, prior to its presentation to CEN This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by August 2011, and conflicting national standards shall be withdrawn at the latest by August 2011 Attention is drawn to the possibility that some of the elements of this document 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: 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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom BS EN 4660-004:2011 EN 4660-004:2011 (E) Introduction 0.1 Purpose This document is produced under contract ASAAC Phase II Contract n°97/86.028 The purpose of the ASAAC Programme is to define and validate a set of open architecture standards, concepts and guidelines for Advanced Avionics Architectures (A3) in order to meet the three main ASAAC drivers The standards, concepts and guidelines produced by the Programme are to be applicable to both new aircraft and update programmes from 2005 The three main goals for the ASAAC Programme are: Reduced life cycle costs Improved mission performance Improved operational performance The ASAAC standards are organised as a set of documents including: A set of agreed standards that describe, using a top down approach, the Architecture overview to all interfaces required to implement the core within avionics system The guidelines for system implementation through application of the standards The document hierarchy is given hereafter: (in this figure the document is highlighted) Standard for Architecture Standard for Software Guidelines for System Issues • • • • Standard for Packaging • • • System Management Fault Management Initialisation / Shutdown Configuration / Reconfiguration Time Management Security Safety Standard for Communications and Network Standard for Common Functional Modules Figure — ASAAC Standard Documentation Hierarchy BS EN 4660-004:2011 EN 4660-004:2011 (E) 0.2 Document structure The document contains the following clauses: Clause 1, Scope Clause 2, Normative references Clause 3, Terms, definitions and abbreviation Clause 4, Generic module specification Clause 5, Module Mechanical Tests Clause 6, Guidelines for a rack slot Clause 7, Typical modular avionics environment Scope The purpose of this standard is to establish uniform requirements for Packaging for the Common Functional Modules (CFM) within an Integrated Modular Avionic (IMA) system, as defined per ASAAC It comprises the module physical properties and the Module Physical Interface (MPI) definitions together with guidelines for IMA rack and the operational environment The characteristics addressed by the Packaging Standard are: Interchangeability:  For a given cooling method all modules conforming to the packaging standard will function correctly when inserted into any rack slot conforming to the standard for the cooling method  All modules conforming to the Module Physical Interface (MPI) definitions for connector, IED and cooling interface will function correctly when inserted into any rack slot conforming to the same MPI definition Maintainability:  All modules are easily removable at first line  No special tools required at first line  No manual adjustment is necessary when installing modules No tool is required for installation or removal of the modules  Mechanical keying is provided that prevents insertion of a module into a rack slot that may cause an unsafe condition The Module Physical Interface definition, contained within this standard, does not include the properties of the signalling used in the optical interface (e.g wavelength) These are covered in EN 4660-003 BS EN 4660-004:2011 EN 4660-004:2011 (E) 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 (including any amendments) applies EN 2101, Aerospace series — Chromic acid anodizing of aluminium and wrought aluminium alloys EN 2284, Aerospace series — Sulphuric acid anodizing of aluminium and wrought aluminium alloys EN 2437, Aerospace series — Chromate conversion coatings (yellow) for aluminium and aluminium alloys EN 4660-001, Aerospace series — Modular and Open Avionics Architectures — Part 001: Architecture EN 4660-002, Aerospace series — Modular and Open Avionics Architectures — Part 002: Common Functional Modules EN 4660-003, Aerospace series — Modular and Open Avionics Architectures — Part 003: Communications/Network EN 4660-005, Aerospace series — Modular and Open Avionics Architectures — Part 005: Software ASAAC2-GUI-32450-001-CPG Issue 01, Final Draft of Guidelines for System Issues 1) — Volume — System Management — Volume — Fault Management — Volume — Initialisation and Shutdown — Volume — Configuration / Reconfiguration — Volume — Time Management — Volume — Security — Volume — Safety ARINC 600, Air transport avionics — Equipment interfaces Def Stan 03-18, Chromate Conversion Coatings (Chromate Filming Treatments) Grades: Standard and Brushing for Aluminium and Aluminium Alloys Def Stan 03-24, Chromic Acid Anodizing of Aluminium and Aluminium Alloys Def Stan 03-25, Sulphuric Acid Anodizing of Aluminium and Aluminium Alloys 1) In preparation at the date of publication of this standard BS EN 4660-004:2011 EN 4660-004:2011 (E) BS 5599, Specification for hard anodic oxidation coatings on aluminium and its alloys for engineering purposes 2) MIL-C-26074E, Coatings, Electroless Nickel Requirements MIL-A-8625E, Anodic Coatings for Aluminium and Aluminium Alloys MIL-C-81706, Chemical Conversion Materials for Coating Aluminium and Aluminium Alloys MIL-C-5541, Chemical Conversion Coatings on Aluminium and Aluminium Alloys Terms, definitions and abbreviations 3.1 Terms and definitions Use of “shall”, “should” and “may” within the standards observe the following rules:  The word SHALL in the text express a mandatory requirement of the standard  The word SHOULD in the text expresses a recommendation or advice on implementing such a requirement of the standard It is expected that such recommendations or advice will be followed unless good reasons are stated for not doing so  The word MAY in the text expresses a permissible practice or action It does not express a requirement of the standard 3.2 Abbreviations AFA Air Flow Around AFT Air Flow Through ARINC Aeronautical Radio Inc ASAAC Allied Standard Avionics Architecture Council CC Conduction Cooled CFM Common Functional Module DAF Direct Air Flow EMC ElectroMagnetic Compatibility IED Insertion Extraction Device IMA Integrated Modular Avionics MBU Multiple Bit Upset 2) Replaces Def Stan 03-26 BS EN 4660-004:2011 EN 4660-004:2011 (E) 6.5.2.2 Cooling requirements The cooling requirements are dependant on the characteristics of the modules to be accommodated, the rack design and the cooling air characteristics The system shall be modelled by the rack integrator to establish the allowable module configurations In use, the System Blue Prints (see EN 4660-001) will hold a record of which module types may be fitted to which slot, together with the module power dissipation for each module type These Blue Prints may be used to ensure a valid configuration 6.6 Air Flow Cooled Interface 6.6.1 Guide Rail Outline drawing 6.6.1.1 Air Flow Through and Direct Air Flow Figure 14 shows the critical dimensions of a guide rail for Air Flow through and Direct Air Flow cooled racks 233.4 218 233.4 max Rack manufacturer specif ic 218 28 20 26 – – 0.1 10 Reference Plane position a) Side C rack guide rail 233.4 218 233.4 max Rack manufacturer specif ic 218 28 b) Side D rack guide rail Reference Plane position Figure 14 — Air Flow Through and Direct Air Flow cooled rack guide rail 30 – 0.1 20 26 – 10 BS EN 4660-004:2011 EN 4660-004:2011 (E) 6.6.1.2 Air Flow Around Figure 15 shows the critical dimensions of a guide rail for an Air Flow Around cooled rack The guide rails are identical for Side C and Side D 233.4 Rack manufacturer specif ic 218 28 1.5 – 0.1 14 26 – 0.1 Reference Plane position Figure 15 — Air Flow Around cooled rack guide rail 6.6.2 Specific requirements for Air Flow Through cooled slot 6.6.2.1 Mechanical requirements 6.6.2.1.1 Sealing Seals may be provided on the rack slot to prevent cooling air escaping at the module/rack slot interfaces The performance requirements for these seals are dependant on the cooling air pressure and allowable leakage Additional sealing between rack slots and at the rack cover may be necessary if the rack is to house air flow around modules 6.6.2.1.2 Compatibility with conduction cooled modules If the slot is to be capable of cooling a conduction cooled module the slot shall provide the following additional features:  Flatness and surface finish requirements as defined in 4.5.1.2.1.1 and 4.5.1.2.1.2  Blanking of cooling air slots, either automatically on insertion of the module or by blanking plugs/plates  Sufficient heat exchange between the rack cooling air and the rack structure to allow conduction cooling 6.6.2.1.3 Compatibility with air flow around cooled modules If the slot is to be capable of cooling an air flow around cooled module the slot shall provide in addition improved sealing around the rack front cover If air flow around modules share the same rack with other module types a blanking plate may have to be installed in a module position between the two to control the air flow This is dependant on the details of the installation and may be determined by thermal modelling 31 BS EN 4660-004:2011 EN 4660-004:2011 (E) 6.6.2.2 Cooling requirements The cooling requirements are dependant on the characteristics of the modules to be accommodated, the rack design and the cooling air characteristics The system should be modelled by the rack integrator to establish the allowable module configurations In use, the System Blue Prints (see EN 4660-005) will hold a record of which module types may be fitted to which slot, together with the power dissipation and air flow rate for each module type These Blue Prints may be used to ensure a valid configuration 6.7 Relationship between Cooling, Connector and IED Rack Interfaces The relationship between the interface elements on the rack, cooling, connector and IED (corresponding to the module’s MPI) are shown in Figure 16 The detail of the IED interface is shown in Figure 17 Cassette Side C Rack Guide Rail Module Reference Plane Connector Mating surface Cassette Side D Rack Guide Rail Detail Figure 16 — Inter-relationship of Rack Physical Interfaces 32 BS EN 4660-004:2011 EN 4660-004:2011 (E) Figure 17 — Detail of IED – Rack interface Typical modular avionics environment These requirements are not necessarily mandatory either on the rack or the module but are provided for guidance This is offered as a candidate for the design of the modules This subclause describes the general environmental specifications for the ASAAC rack Environmental levels applicable to CFMs will be modified by the rack from those given here The environmental conditions applicable to IMA depend on:  The zone where the equipment is located within the aircraft  The different types of aircraft The equipment design should take into account the overall environmental conditions defined in the following subclauses as a general operational environment The test conditions not necessarily apply at module level and are not mandatory Modules shall be designed to meet the environmental conditions of the project on which they are to be used 33 BS EN 4660-004:2011 EN 4660-004:2011 (E) 7.1 Ambient pressure (altitude) The rack is expected to withstand and operate in the following pressure conditions Table — Ambient pressure in relation to altitude Sea level 55 000 ft 65 000 ft Maximum Ambient 115 kPa abs 11.1 kPa abs 7.6 kPa abs Minimum Ambient 87.3 kPa abs 7.1 kPa abs 3.6 kPa abs – – Maximum Rate of Change 318 kPa/min increasing 220 kPa/min decreasing The test procedure is described in MIL-STD-810E, method 500.3, procedure II NOTE This specification is only applicable in case of sealed housings or trapped zones 7.2 Humidity Normal operation is Required, when relative humidity is equal to 98 % throughout the temperature range, even when this humidity involves an internal or external condensation In case of storage, equipment must be able to endure a relative humidity of 98 % and a maximum absolute humidity of 27 g/kg Racks and modules materials must operate correctly and resist to the effects of this warm and humid atmosphere which levels are defined in MIL-STD-810E, method 507.3, procedure III (aggravated test cycle) 7.3 High and low temperatures Racks and modules should function correctly when stored, manipulated and operated under low and high temperature conditions without experiencing physical damage or deterioration in performance Normal operating is expected in the following conditions 34 BS EN 4660-004:2011 EN 4660-004:2011 (E) 7.3.1 Temperature environmental conditions Table — Temperature environmental conditions - Conditioned bay Mode Temperature range Operation conditions Flight Continuous + 70 °C maximum − 40 °C minimum Sea level Flight Continuous + 58 °C maximum − 40 °C minimum 25 000 ft Flight Continuous + 40 °C maximum − 40 °C minimum 40 000 ft Flight Continuous + 20 °C maximum − 40 °C minimum 55 000 ft Ground Soak + 70 °C maximum − 40 °C minimum Operating Ground Soak + 90 °C maximum − 40 °C minimum Non-operating Table — Temperature environmental conditions - Unconditioned bay Mode Temperature range Operation conditions Flight Continuous + 96 °C maximum − 40 °C minimum Sea level Flight Continuous + 73 °C maximum − 51 °C minimum 25 000 ft Flight Continuous + 40 °C maximum − 54 °C minimum 40 000 ft Flight Continuous + 40 °C maximum − 54 °C minimum 55 000 ft Ground Soak + 70 °C maximum − 40 °C minimum Operating Ground Soak + 90 °C maximum − 40 °C minimum Non-operating Test method is described in MIL-STD-810E, method 501.3, procedure I and method 502.3, procedure I 7.3.2 Storage temperatures Table — Temperature environmental conditions - Storage 7.4 Mode Temperature range Operation conditions Storage + 90 °C maximum − 60 °C minimum Sea level Thermal shocks In normal operating, thermal shocks due to rapid altitude variations, for example, may occur Racks and modules must withstand these sudden changes in the surrounding atmosphere without physical damage or deterioration in performance 35 BS EN 4660-004:2011 EN 4660-004:2011 (E) The maximum rate can reach 10 °C per minute in total spectrum of applicable temperatures The test method is described in MIL-STD-810E, method 503.3 Test conditions Table — Thermal shocks T1 T2 Number of cycles Rate − 57 °C + 90 °C 10 °C/min 7.5 Salt spray Racks and installed modules must withstand the effects of an aqueous salt atmosphere by appropriate protection against corrosion The test method is described in MIL-STD-810E, method 509.3, procedure I Test conditions Salt concentration 5% Temperature 35 °C Duration 96 hours Alternatively, the equipment shall be tested in accordance with BS3G100 Part 2, section 3, subsection 3.8, Severity 7.6 Vibrations Vibration testing is performed to determine the mechanical resistance of the rack to stresses expected in its shipment and application environment Racks and modules should be designed without failure in respect of MIL-STD-810E, method 514.4 (Vibration Endurance Test) 7.6.1 Sinusoidal vibrations The following test conditions will be applied to each axis X, Y and Z: Table — Sinusoidal vibrations Test conditions spectrum 36 20 - 50 Hz 1g 50-2 000 Hz 10 g Logarithmic sweep speed octave/minute Number of cycles BS EN 4660-004:2011 EN 4660-004:2011 (E) 7.6.2 Random vibrations The following test conditions will be applied for each axis X, Y, and Z: Power Spectral Density (PSD) (Functional) (Endurance) 0.04 g /Hz 0.17 g /Hz 7.6.3 Frequencies 20 - 2000 Hz Duration hour Gunfire vibrations The gunfire vibration test is performed to ensure that equipment mounted in an aircraft with onboard guns can withstand the vibration levels caused by the excess pressure pulses emitted from the gun muzzle Racks and modules are expected to meet such conditions when subjected to the vibration tests described in MIL-STD-810E, method 519.4, procedure I The spectra will be in accordance with Fig 519.4-1 and Table III Equipment found most susceptible to gunfire is this equipment that is usually located within a 3-foot radius of the gun muzzle and is mounted on the structural surface exposed to the gun blast Next in order of failure susceptibility is equipment mounted on drop-down doors and access panels, equipment mounted in cavities adjacent to and near the aircraft surface structure, and finally, equipment located in the interior of the vehicle 7.6.4 Combined vibrations (Helicopter) On this type of aircraft, the vibration spectrum is characterised by a random noise on which vibration peaks are superposed These peaks are generated by rotating elements:  main rotor and tail rotor,  transmissions The peak values are dependant on the type of helicopter 7.7 Accelerations Racks and modules must structurally withstand the g-forces that are expected to be induced by acceleration in the service environment and function without degradation during and following exposure to these forces The test method is described in MIL-STD-810E, method 513,4 procedure I (structural) and II (operational) The load parameters are the following ones 7.7.1 Rotational accelerations The following test conditions will be applied: Table — Rotational accelerations Parameter Value Roll Rate +/− rad/s Roll Acceleration +/− 17 rad/s Pitch Rate +/− 0.5 rad/s Pitch Acceleration +/− rad/s Yaw Rate +/− rad/s Yaw Acceleration +/− rad/s 2 37 BS EN 4660-004:2011 EN 4660-004:2011 (E) 7.7.2 Transversal accelerations The following test conditions will be applied: Table — Transversal accelerations Parameter Value Longitudinal 25 g aft Lateral +/− 8.75 g Vertical +/− 12.5 g Pitch Acceleration +/− rad/s 7.8 Mechanical shocks Racks and modules must withstand relatively infrequent, non repetitive shocks or transient vibrations encountered in handling, transportation and service environment The test method is described in MIL-STD-810E, method 516.4-4 Shock pulse shape, peak value and duration are defined in figure 516.4-4 7.8.1 Functional shocks The test method is described in MIL-STD-810E, procedure I The elements should withstand the following values without any damage: Table 10 — Functional Shocks 7.8.2 Test Procedure Peak Acceleration TE Cross Over Frequency Functional Test for Flight Equipment 20 g 6-9 ms 45 Hz Functional Test for Ground Equipment 40 g 6-9 ms 45 Hz Crash Hazard Test for Flight Equipment 40 g 6-9 ms 45 Hz Crash Hazard Test for Ground Equipment 75 g 3.5-5 ms 80 Hz Bench handling This test procedure described in MIL-STD-810E, method 516.4, procedure VI is applied to equipment that may experience bench or bench-type maintenance It is used to determine the ability of the test item to withstand the usual level of shock encountered during typical bench maintenance or repair 7.8.3 Crash hazard The test method is described in MIL-STD-810E 516.4, procedure V It is applied to equipment mounted in an air or ground vehicle that could break loose from its mounts and present a hazard to vehicle occupants It is intended to verify the structural integrity of equipment mounts during simulated crash conditions 38 BS EN 4660-004:2011 EN 4660-004:2011 (E) 7.8.4 Catapult launch, arrested landing The test method is described in MIL-STD-810E 516.4, procedure IX It is intended for equipment mounted in or on fixed-wing aircraft that are subjected to catapult launches and arrested landings 7.9 Contamination resistance Most of liquid or gaseous fluids used in the various aircraft systems shall be considered as possible pollution agents for the generally non metallic components of the equipment with which they might accidentally come into contact The case of cleaning agents is considered too This contact shall be made by spraying or exceptionally by immersion These potential polluting products are the following ones (non exhaustive list):  hydraulic fluids,  fuels and additives (antifreeze, antistatic, anticorrosive, fungicide),  lubricants for engines,  various greases,  extinguisher liquids,  cleaning fluids, etc Racks and modules will be chosen to resist the effects of contamination by any of these fluids No degradation (bulk materials, polymers, paints, seals ) is accepted and fluid retention zones should be avoided The test method is described in GAM-EG-13, Instalment 16 or BS3G100, part 2, section 3, subsection 3.12 for class A 7.10 Flame resistance Flame resistance tests shall determine the behaviour of samples of polymeric matrix composites in which racks are made Toxic fumes due to combustion of these materials must be avoided The A UL-94-VO classification is recommendable The test procedure and approval criteria are specified by FAR 25, Appendix F Regulations The equipment will be designed using materials which not support combustion The test method is described in BS3G100, part 2, section 3, subsection 3.13 7.11 Fungus resistance All materials exposed to fungal contamination must be non-nutritive When not practicable, a suitable fungicide agent or other means should be used to protect the materials The test method is described in MIL-STD-810E, method 508.4 7.12 Rain Racks and modules will be designed in such a way that accumulation zones will be eliminated The test method is described in MIL-STD-810E, method 510.3 39 BS EN 4660-004:2011 EN 4660-004:2011 (E) 7.13 Acoustic noise The test method is described in MIL-STD-810D, Method 515.3, Procedure II, Cat C 7.14 Electromagnetic environment A summary of all environmental conditions is presented They are representative for an equipment to be installed in non-metallic aircraft respectively in a relatively open area of a metallic aircraft The most severe requirement will determine the design of the equipment case Table 11 — Summary of environment and bonding environmental Conditions Requirement Signal Level Low Frequency Magnetic Fields 400 Hz 10 ms Spike 0.15 ms Spike 20 A through wire wrapped around equipment case in 0.3 m distance or 100 A/m ElectroMagnetic Radiation CW-Modulations Pulse-Modulations Radiated Emission ElectroStatic Discharges (ESD)s Bonding Cat C of ED14/RTCA DO 160 D No perturbation to other surrounding CFMs Conducted CW-Signals Conducted Transients 200 V/m from 10 kHz up to 40 GHz Shielded compartment Required Waveform > kA Racks and modules when installed, not damaged by an ESD of 16 000 V Modules when not installed, not damaged by an ESD of 000 V < 25 mΩ between conducting parts < mΩ connectors/bonding facility Good surface-to-surface contacts 7.15 Explosive atmosphere Racks or modules will not cause ignition in an ambient explosive gaseous atmosphere complying with the environmental conditions of MIL-STD-810E, Method 511.3, Procedure 7.16 Nuclear, Biological and Chemical (NBC) Hazards Racks or modules may not be subjected to a direct attack during NBC Hostilities, although contamination may occur within the environment of the avionics bay of the aircraft and may also occur during maintenance procedures or during storage Materials and finishes should be resistant against and impermeable to contaminants and be able to be decontaminated Surfaces and finishes should be smooth and textureless Special attention should be paid to eliminating crevices, blind holes or traps and joints where capillary action could occur Racks should be designed to be as plain and simple as possible in order to reduce the possibility of contaminant or decontaminant entrapment 40 BS EN 4660-004:2011 EN 4660-004:2011 (E) Modules should be designed for easy handling 7.16.1 Nuclear threats In this domain, the most critical and demanding specification level is that due to human limitations However, the following elements give some aspects of the System Nuclear Protection Environmental conditions Components within racks and modules will be exposed to the same Nuclear environment 7.16.2 Nuclear radiation The following Initial Nuclear Radiation should be considered Table 12 — Initial Nuclear radiation conditions Dose Level Total Dose (Neutron and Gamma) 150 cGy (Ti) Maximum Gamma Contribution 70 cGy (Ti) Peak Gamma Dose Rate 1x10 cGy/ (Silicon) Maximum Neutron Contribution 110 cGy (Ti) 10 Maximum Neutron Flux 6x10 n/cm²/s The figures given are compatible with a manned aircraft Unmanned aircraft, shipborne equipment and ground vehicle environmental conditions may differ considerably 7.16.2.1 Nuclear hardening The following categories of Nuclear Hardening should be recognised Table 13 — Nuclear hardening conditions Category Attributes I No malfunction allowed II Malfunction allowed All functions and data must be available again after a time shorter than the time constant of the circuit III Malfunction allowed All functions and data must be available again after a time tbd IV Malfunction allowed but no damage After a Nuclear Event, a Return to Base Capability should be maintained and Mission Performance should still be possible albeit in a degraded role The ultimate design feature is complete Nuclear Hardening of all aircraft systems (Category I above, at the levels shown in Table 12) 7.16.3 Biological and Chemical These threats include Chemical Warfare Agents in the form of gas, aerosols, liquids or gels as well as Biological Agents which can gain access to the Crew Chemical Agents can also have an effect on the differing materials making up the airframe and its contents etc., causing corrosion, structural fatigue and deterioration 41 BS EN 4660-004:2011 EN 4660-004:2011 (E) Racks and modules should function as specified when exposed to Biological and Chemical attack The Decontaminant Products, some of which are aggressive to the materials they are used on, should also be taken into account 7.17 Sand and dust The rack should withstand a Sand and Dust test according to MIL-STD-810E The modules not meet to withstand such a test: the connectors will be cleaned before insertion in any rack slot to avoid sand and dust being present between the two connector halves 7.18 Single Event Upset / Multiple Bit Upset The hardware and software implementation solutions shall consider the possibility of SEU (Single Event Upset) and MBU (Multiple Bit Upset, especially MBU leading to Single Word Multiple Upset) due to particle environment (radiations for example: neutrons, protons, heavy ions, etc.) at high flight altitude and latitude 7.19 Module Tempest Modules shall be designed such that electromagnetic coupling effects between data communication and power supply not result in unintentional transmission of data off modules This impacts the mechanical and electrical design of all processing and networking modules that shall provide sufficient electromagnetic decoupling between internal areas to ensure that no unintentional transmission can be observed on the module electrical interfaces 42 This page deliberately left blank 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