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1、BRITISH STANDARD AEROSPACE SERIES BS G 260:1996 ISO 2669:1995 Environmental tests for aircraft equipment Steady-state acceleration ICS 49.020 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:39:35 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 260:1996 This B
2、ritish Standard, having been prepared under the direction of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 June 1996 BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference ACE/58 Draft for
3、 comment 89/75587 DC ISBN 0 580 25627 8 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee ACE/58, Environmental and operating conditions for aircraft equipment, upon which the following bodies were represented: Civil Aviati
4、on Authority Federation of the Electronics Industry Ministry of Defence Society of British Aerospace Companies Society of Environmental Engineers Amendments issued since publication Amd. No.DateComments Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:39:35 GM
5、T+00:00 2006, Uncontrolled Copy, (c) BSI BS G 260:1996 BSI 01-2000i Contents Page Committees responsibleInside front cover National forewordii Introduction1 1Scope1 2Normative reference1 3Apparatus1 4Equipment mounting2 5Classification of tests2 6Test sequence3 7Acceleration severity grades3 8Proced
6、ures3 9Information to be included in the relevant equipment specification6 Annex A (normative) Additional accelerations7 Figure 1 Direction of aircraft acceleration4 Table 1 Equipment severity grades2 Table 2 Classification of tests3 Table 3 Equipment categories4 Table 4 Acceleration severity grades
7、 (functional test)5 Table 5 Acceleration severity grades (structural test)5 Table A.1 Additional accelerations7 List of referencesInside back cover Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:39:35 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 260:1996
8、ii BSI 01-2000 National foreword This British Standard has been prepared by Technical Committee ACE/58 and is identical with ISO 2669:1995 Environmental tests for aircraft equipment Steady-state acceleration, published by the International Organization for Standardization (ISO). NOTEThe latest editi
9、on of an Aerospace series standard is indicated by a prefix number. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immuni
10、ty from legal obligations. Cross-reference Publication referred toCorresponding British Standard ISO 7137:1995BS 4G 229:1996 Schedule for environmental conditions and test procedures for airborne equipment (Identical) Summary of pages This document comprises a front cover, an inside front cover, pag
11、es i and ii, pages 1 to 10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: London South Bank University, London South Bank Uni
12、versity, Sat Dec 09 02:39:35 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 260:1996 BSI 01-20001 Introduction The tests specified in this International Standard aim to determine the performance characteristics and to confirm the structural integrity and safety of airborne equipment and airborne eq
13、uipment mountings when they are subjected to gradually changing acceleration forces generated by an aircraft, manoeuvre such as turn, pull-out, roll, etc. For example, the tests would be expected to indicate: a) any change in operating state and any variations in performance; b) any jamming occurrin
14、g in moving parts and any variation in their path; c) any reduction in the free travel and change in the suspension characteristics of the anti-vibration mountings that could damage the operating state and capability of anti-vibration; d) any breakage or any weakness in the fastenings mounting devic
15、es or structure of the equipment that could constitute a hazard to the aircraft or its occupants. 1 Scope This International Standard specifies two types of steady-state acceleration test and establishes five severity grades of acceleration forces used to simulate a gradually changing acceleration e
16、nvironment representative of that which civil aircraft equipment can encounter in operational use. The emergency landing case is not within the scope of this International Standard; reference should be made to ISO 7137 for this case. 2 Normative reference The following standard contains provisions w
17、hich, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility
18、 of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 7137:, Aircraft Environmental conditions and test procedures for airborne equipment1). 3 Apparatus 3.1 General characteristics 3.1.1 A centr
19、ifuge should be used for producing the required acceleration forces. 3.1.2 In special cases, if stated by the relevant equipment specification, inflight testing or any other method that can produce linear acceleration may be used instead of a centrifuge. 3.1.3 The apparatus shall be capable of produ
20、cing the specified acceleration forces within 10 % at all points in the equipment. 3.1.4 The apparatus shall be fitted with the electrical, hydraulic and/or pneumatic input and output connections needed to operate the equipment under test and to conduct operational checks. The loss of the connection
21、s shall not exceed the limit specified in the relevant specification. 3.1.5 The test apparatus shall be equipped with an adjustable acceleration system, and any additional vibration due to the test apparatus shall be maintained within the tolerance specified in the relevant specifications. 3.1.6 The
22、 centrifuge shall be equipped with an adjustable mass balance system to compensate for any out-of-balance forces due to the mass of the test item. 3.2 Special cases 3.2.1 If, because of the excessive size of the equipment, it is not possible to maintain the tolerance specified in 3.1.3 at all points
23、 in the equipment, the relevant equipment specification may relax requirements on those parts not considered to be sensitive to specified acceleration forces. 3.2.2 During functional tests in vertical directions carried out with equipment sensitive to gravity or inversion and which could cause malfu
24、nctions, a special centrifuge, inflight test bed or other apparatus which reproduces the required acceleration shall be used. 3.2.3 Care should be taken when interpreting results of functional performance tests carried out on equipment subjected to acceleration tests using a centrifuge, if the equip
25、ment contains rotating parts with appreciable moments of inertia (e.g. a rate gyro). The relevant equipment specification shall state if the equipment may be tested on a centrifuge, if it is necessary to use other apparatus, or if special requirements for the tests need specifying. 1) To be publishe
26、d. (Revision of ISO 7137:1992) Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:39:35 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 260:1996 2 BSI 01-2000 3.2.4 Acceleration grade 0 is defined as a gradually changing acceleration which causes equipment to be
27、come weightless. For equipment sensitive to zero gravity, a special test procedure may be required and should be detailed in the relevant equipment specification. 3.3 Monitor system 3.3.1 An acceleration pickup, an angular velocity pickup or other method may be used to measure acceleration forces di
28、rectly or indirectly. The accuracy of the acceleration measuring device shall be one-third of the tolerance specified in the relevant equipment specification or better. In some cases, several accelerometers may be located on the equipment under test to determine the acceleration at various places on
29、 the equipment. 3.3.2 When the acceleration is measured with an angular velocity pickup, the angular velocity may be defined by using the following equation: 3.3.3 When the acceleration is measured using an acceleration pickup, it may be located, in accordance with practice, at the geometric centre,
30、 the centre of mass, or the rotary surface, depending on the position of sensitive parts of the equipment under test. 4 Equipment mounting 4.1 Orientation The equipment under test shall be mounted on the apparatus in such a way that it can be successively orientated in the six directions of accelera
31、tion defined by an orthogonal reference system. The relevant equipment specification shall define the reference system. 4.2 Mounting method The orientation may be set by using an adjustable table which is integral with the apparatus or with a special fixture attached to the apparatus. The equipment
32、shall be attached to the adjustable table or fixture by its fastenings or mounting devices, as defined in the installation manual for the equipment. If equipment fitted with an absorber is to be tested, the relevant equipment specification shall define whether the equipment should be installed toget
33、her with the absorber on the centrifuge. 4.3 Supply connections The connection and orientation to the equipment of any electrical, hydraulic or pneumatic supplies shall simulate as closely as possible those used in practice. 5 Classification of tests 5.1 Severity The equipment shall be classified in
34、 accordance with the appropriate severity grade given in Table 1 as a function of environmental and operational conditions. For light and transport aircraft, grade 1 or 2, as applicable, shall be stated in the relevant equipment specification. Table 1 Equipment severity grades 5.2 Types of test Two
35、types of steady-state acceleration test are specified in Table 2. The relevant equipment specification shall state which type of test is to be carried out. 5.3 Categories of equipment The equipment under the imposed acceleration forces shall be classified in accordance with requirements of function,
36、 structural integrity and safety as shown in Table 3. The relevant equipment specification shall state the category of the equipment. where nis the rotational frequency of the arm, in revolutions per minute; ais the acceleration value required by the test, in numbers of g (standard acceleration of f
37、ree fall: gn= 9,806 65 m/s2); dis the distance, in metres, from the rotary shaft of the centrifuge to the position on the equipment under test at which the acceleration value a is to be applied. n2 a 0,0012d - -= Equipment severity grade Intended for installation in 0 Equipment subject to zero gravi
38、ty (e.g. spacecraft) 1Transport aircraft Light aircraft 2 3Helicopters 4 High-performance aircraft Aerobatic aircraft Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:39:35 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 260:1996 BSI 01-20003 Table 2 Classific
39、ation of tests 6 Test sequence 6.1 General case For category A and category B equipment, the functional and structural integrity tests shall be carried out in the following order: a) one functional test with performance check in accordance with 8.1 once in each of the six attitudes; b) one structura
40、l integrity test with performance check in accordance with 8.2 once in each of the six attitudes. For category C equipment, the functional and structural tests are identical. 6.2 Special cases In order to reduce the number of operations necessary for re-orientating the equipment on the test apparatu
41、s, the structural integrity test may immediately follow the functional test unless prohibited by the relevant equipment specification. 7 Acceleration severity grades Functional testing shall be carried out in accordance with Table 4. Structural testing shall be carried out in accordance with Table 5
42、. Directions of the aircraft acceleration are shown in Figure 1. 8 Procedures 8.1 Functional test procedure (all categories) The procedures specified in 8.1.1 to 8.1.4 shall be repeated in each of the six attitudes, unless the equipment under test is symmetrical in both structure and performance. In
43、 this case, it may be tested in only one of the six attitudes, provided the acceleration is that for the most severe mounting attitude. The relevant equipment specification may waive the test requirement for any of the six attitudes in which the equipment is known to be insensitive to acceleration.
44、8.1.1 Initial measurements Mount the equipment on the test apparatus. Carry out a visual check of the appearance and mounting attitudes of the equipment. Operate the equipment and check the electrical and mechanical performance parameters as stated in the relevant specification. 8.1.2 Acceleration t
45、est Operate the equipment in accordance with the functional test given in the relevant equipment specification for a minimum period of 5 min. With the equipment still operating, progressively increase the acceleration to the severity grade specified for the equipment category over a minimum period o
46、f 15 s. Maintain this acceleration for a minimum of 60 s during which time functional performance measurements should be made. Progressively decrease the acceleration to zero taking at least 15 s. Repeat the procedure for all attitudes specified by the relevant equipment specification. 8.1.3 Interme
47、diate measurements During the period of increasing or decreasing acceleration, the equipment operating state shall be monitored. During the period of constant acceleration, the performance parameters shall be checked for compliance with the requirements stated in the relevant specification. Type of
48、testPurpose and requirement of test 1 Functional1) To check the good running order of the equipment under the imposed acceleration forces. 2) The equipment shall be in operation during the acceleration phase and the performance shall be monitored (see 8.1.2). 2 Structural1) To check equipment for st
49、ructural integrity under the imposed acceleration forces, i.e. for structural strength or stiffness of the equipment. 2) To check the equipment and its mounting for safety, i.e. for any structural damage that would constitute a hazard to the aircraft or its occupants. 3) Normally, the equipment shall not be in operation during the acceleration phase. Where it is essential for equipment to operate correctly in emergency situations (e.g. crash recorder) the performance of the equipment shall be monitored (see Table 3, category C).