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1、BRITISH STANDARD BS G 190:1964 Specification for Cabin altimeters for aircraft UDC 629.13.052:531.787.2 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:24:47 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 190:1964 This British Standard, having been approved
2、by the Aircraft Industry Standards Committee and endorsed by the Chairman of the Engineering Divisional Council, was published under the authority of the General Council of the Institution on 22 October 1964 BSI 02-2000 The following BSI references relate to the work on this standard: Committee refe
3、rence ACE/30 Draft for comment D63/10695 ISBN 0 580 34541 6 Foreword This British Standard has been prepared to cover the requirements of aircraft cabin altimeters. The optimum accuracy specified for the instruments is related to the cabin altitude and temperature ranges of typical transport aircraf
4、t. The standard provides for two grades of instrument. One is primarily intended to be used by the crew as an accurate monitor of the performance of the aircraft pressurization system: the other grade, having lesser accuracy, is intended to be used by the pilot as a monitor to check that the air pre
5、ssure within the cabin is adequate for the well-being of the passengers and crew. The standard requires reference to the following British Standards: BS 2G 100, General requirements for electrical equipment and indicating instruments for aircraft. BS G 101, General requirements for aircraft indicato
6、rs: presentation and case sizes. NOTEThe figures in British units are to be regarded as the standard. A table for the approximate conversion of feet to metres is given in Appendix B. More accurate conversions should be based on the tables in BS 350, “Conversion factors and tables”. A British Standar
7、d 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 immunity from legal obligations. Summary of pages This document comprises a front cover, an
8、 inside front cover, pages i and ii, pages 1 to 4 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. Amendments issued since publication Amd. No.DateComments Licensed
9、 Copy: London South Bank University, London South Bank University, Sat Dec 09 02:24:47 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 190:1964 BSI 02-2000i Contents Page ForewordInside front cover 1Scope1 Section 1. General requirements 2General construction1 Section 2. Particular requirements 3Con
10、struction1 4Calibration1 Section 3. Tests 5General1 Type tests 6Ranging and accuracy test2 7Hysteresis test2 8Friction test2 9Position test3 10Temperature tests3 11Overload tests3 12Vibration test3 13Acceleration test3 14Climatic test3 15Waterproofness test3 Production routine test 16Ranging and acc
11、uracy, hysteresis, friction, position and overload tests3 Production quality test 17Temperature and resonance tests3 Appendix A Serviceability tests4 Appendix B Conversion of British to metric units4 Table 1 Permissible errors for Grade I instruments2 Table 2 Permissible errors for grade II instrume
12、nts2 Table 3 Hysteresis tolerances2 Table 4 Friction tolerances2 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:24:47 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02
13、:24:47 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 190:1964 BSI 02-20001 1 Scope This British Standard specifies the general design requirements and test procedures for two grades of pressure cabin altimeters for aircraft: Grade I: for use with the pressurization control system, having a range o
14、f 2 000 ft to + 20 000 ft. Grade II: for use by the pilot, having a range of 2 000 ft to + 30 000 ft. Section 1. General requirements 2 General construction a) The design and construction of the instrument shall comply with the relevant requirements of BS 2G 100 and BS G 101. b) The preferred case s
15、izes, as shown in BS G 101, are: Grade I: Type 3, Type 5 and Type 8. Grade II: Type 2, Type 4 and Type 7. Section 2. Particular requirements 3 Construction a) The instrument shall contain an absolute pressure measuring mechanism driving a single pointer. b) In order to withstand cabin pressurization
16、 whilst the aircraft is on the ground, the instruments shall be capable of withstanding an absolute pressure of 2 000 millibars (approximately two atmospheres) or, for Grade I instruments, any lower overload pressure quoted in the individual specification, with a minimum of 1 129 millibars ( 3 000 f
17、t). NOTEIf Grade I instruments are declared to an overload pressure of less than 2 000 millibars, it is essential that the necessity for removing the instrument from the aircraft during ground pressurization tests exceeding the overload pressure be stressed in the relevant maintenance instructions.
18、c) The instrument shall be capable of withstanding a pressure equivalent to an altitude 10 000 feet higher than the maximum calibrated range of the instrument. d) The design and construction of the instrument, including the case pressure communicating vent, shall be such that it satisfies the requir
19、ements of BS 2G 100-2 in respect of Grade B drip proof equipment. e) The dial of Grade I instruments shall be marked at intervals of 2 000 ft with subdivisions at 1 000 and 500 ft intervals. f) The dial of Grade II instruments shall be marked at 5 000 ft intervals with subdivisions at 1 000 ft inter
20、vals. g) The scale of Grade I instruments may extend over 360 degrees so that the zero height and 20 000 ft positions are coincident at the top vertical position, or the scale may subtend less than 360 degrees. In either case stops shall be fitted to ensure that at altitudes above 20 000 ft the poin
21、ter does not go above/the 20 000 ft position. h) The scale of Grade II instruments shall have a gap between the zero and full scale positions, and shall be fitted with stops complying with the requirements of BS G 101. j) The instruments shall be capable of operation down to 2 000 ft (1088.7 milliba
22、rs) and the dial shall be suitably marked to indicate this point. 4 Calibration The relationship between height and pressure to which the instruments are calibrated shall be in accordance with ICAO Document 7488, May 1954. Section 3. Tests 5 General a) Tests shall be made to prove compliance with al
23、l the requirements of this British Standard. It is not intended or recommended that complete tests shall be made on every instrument supplied. Three kinds of tests, therefore, are specified as follows: Type tests: to be made on representative samples to prove the design. Production routine tests: to
24、 be made on all instruments manufactured in accordance with the standard. Production quality tests: to be made on samples as specified in the individual specification. b) For the guidance of users, minimum tests recommended to verify the serviceability of instruments manufactured in compliance with
25、this British Standard are indicated in Appendix A. c) Vibration not exceeding 0.2g shall be applied to the instruments during the performance tests, except the friction test specified in Clause 8, to remove the effects of friction. NOTEVibration of this order is attainable with a total amplitude of
26、0.04 mm and a frequency of 50 c/s. Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:24:47 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 190:1964 2 BSI 02-2000 d) No pressure cycling or exercising other than that produced by normal variation of terrestial bar
27、ometric pressure shall be applied to the instruments for a period of not less than 16 hours before the ranging tests are performed. e) Readings taken from barometers used to test the altimeters shall be corrected for latitude and temperature. f) Unless otherwise specified, tests shall be made at a t
28、emperature of 20 5 C. Table 1 Permissible errors for Grade I instruments Type tests 6 Ranging and accuracy test With the instrument in the normal position with the dial upright and in a vertical plane, the errors shall not exceed the amounts specified in Table 1 or Table 2, as appropriate, when test
29、ed with pressure increasing and decreasing at a nominal rate of 1 000 ft/min. Table 2 Permissible errors for grade II instruments 7 Hysteresis test The hysteresis as determined from the errors at the same barometric pressure, with the pressure decreasing and increasing in the ranging test, shall not
30、 exceed the limits specified in Table 3. Table 3 Hysteresis tolerances 8 Friction test At three approximately equally spaced increments of the dial, the pointer shall be brought to the desired reading and then held constant, the instrument being carefully isolated from vibration. Two readings shall
31、then be taken, the first whilst the instrument remains undisturbed and the second after the instrument has been tapped until the pointer no longer moves. The difference between the two readings shall not exceed the tolerances specified in Table 4. This test may be combined with the ranging test but
32、in any event shall be performed with both increasing and decreasing pressure. Table 4 Friction tolerances HeightPressure Permissible errors ft 2 000 0 2 000 3 000 4 000 6 000 7 000 8 000 10 000 12 000 14 000 16 000 18 000 20 000 millibars 1088.7 1013.25 942.13 908.12 875.10 811.99 781.85 752.62 696.
33、81 644.41 595.24 549.15 506.00 465.63 ft + and 250 150 150 100 100 100 100 200 300 300 300 400 500 500 HeightPressurePermissible errors ft 2 000 0 5 000 10 000 15 000 20 000 25 000 30 000 millibars 1088.7 1013.25 843.07 696.81 571.82 465.63 376.01 300.89 ft + and 500 500 500 500 500 500 500 600 Heig
34、ht Permissible error Grade I instruments Grade II instruments ft 0 to 10 000 above 10 000 ft 150 300 ft 250 500 Height Tolerance Grade I instruments Grade II instruments ft 0 to 10 000 above 10 000 ft 100 200 ft 200 400 Licensed Copy: London South Bank University, London South Bank University, Sat D
35、ec 09 02:24:47 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 190:1964 BSI 02-20003 9 Position test The change in reading shall not exceed 100 feet when the instrument is tilted 90 in any direction from the normal position. 10 Temperature tests a) The instrument shall be tested over the range 0 C t
36、o + 40 C and the errors shall not exceed those quoted in Table 1 or Table 2, as appropriate. b) The instrument shall be tested at 20 C and + 50 C and the errors shall not exceed twice those quoted in Table 1 or Table 2, as appropriate. c) The instrument shall not be deranged by being subjected to te
37、mperatures of 40 C and + 70 C. After this test the instrument shall comply with the requirements of Clauses 6, 7 and 8 of this standard. 11 Overload tests a) Positive pressure. The instrument shall be subjected to an absolute pressure of 2 000 millibars, or for Grade I instruments to the declared ov
38、erload pressure, for five minutes. Immediately following this test the tolerances specified in Table 1 or Table 2, as appropriate, shall not be exceeded by 100 feet; when retested within 16 hours the tolerances shall be as specified in Table 1 or Table 2, as appropriate. b) Negative pressure. The in
39、strument shall be subjected for five minutes to a pressure equivalent to an altitude 10 000 feet higher than the maximum calibrated range of the instrument. The calibration shall be checked immediately afterwards at 20 000 ft, 10 000 ft and 0 ft and shall be within the tolerances of Table 1 or Table
40、 2, as appropriate. 12 Vibration test The instrument, without vibration mountings, shall be subjected to vibration tests in accordance with BS 2G 100-2, as required by the individual specification. 13 Acceleration test The instrument shall be subjected to acceleration tests in accordance with BS 2G
41、100-2, as required by the individual specification. 14 Climatic test The instrument shall be subjected to the tests specified for climatic Class 2 equipment in BS 2 G 100-2. The functioning test, to be made at the end of the third day and repeated at the end of the test cycles, shall consist of rang
42、ing and accuracy, hysteresis and friction tests at the following altitudes: The indicated altitudes shall be within the appropriate tolerances shown in Table 1 to Table 4. 15 Waterproofness test The instrument shall be subjected to the drip test specified in BS 2G 100-2. Production routine tests 16
43、Ranging and accuracy, hysteresis, friction, position and overload tests Each instrument shall satisfactorily fulfil the requirements of the tests specified in Clauses 6, 7, 8, 9 and 11. Production quality tests 17 Temperature and resonance tests Sample instruments, selected as specified in the indiv
44、idual specification, shall satisfactorily fulfil the requirements of the tests specified in Clauses 10 and 12, except that for the purposes of the test in Clause 12 only the requirements of BS 2G 100-2 for the resonance search test shall apply. 0 ft4 000 ft8 000 ft20 000 ft. Licensed Copy: London So
45、uth Bank University, London South Bank University, Sat Dec 09 02:24:47 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 190:1964 4 BSI 02-2000 Appendix A Serviceability tests The minimum tests recommended to verify the serviceability of instruments manufactured in compliance with this British Standar
46、d are as follows: 1) Ranging and accuracy test (Clause 6) at the following test points: 2) Friction Test (Clause 8). Appendix B Conversion of British to metric units Approximate metric equivalents of the heights quoted in this British Standard are shown in the following table. More accurate conversi
47、ons should be based on the tables in BS 350. Grade I instrumentsGrade II instruments 0 ft0 ft 6 000 ft5 000 ft 10 000 ft10 000 ft 20 000 ft20 000 ft 30 000 ft ftmftm 100 150 200 250 300 400 500 600 1 000 2 000 3 000 4 000 5 000 30.5 45.7 61.0 76.2 91.4 121.9 152.4 182.9 304.8 610.0 914.4 1 219.2 1 5
48、24.0 6 000 7 000 8 000 10 000 12 000 14 000 15 000 16 000 18 000 20 000 25 000 30 000 1 828.0 2 133.6 2 438.4 3 048.0 3 657.6 4 267.2 4 572.0 4 876.8 5 486.4 6 096.0 7 620.0 9 144.0 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:24:47 GMT+00:00 2006, Uncontr
49、olled Copy, (c) BSI blank Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:24:47 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 190:1964 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standar
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