1、BRITISH STANDARD BSG190:1964 Specification for Cabin altimeters for aircraft UDC 629.13.052:531.787.2BSG190:1964 This BritishStandard, having been approved by the Aircraft Industry Standards Committee and endorsed by the Chairman ofthe Engineering Divisional Council, was published under theauthority
2、 of the General Council of the Institution on 22October1964 BSI 02-2000 The following BSI references relate to the work on this standard: Committee reference ACE/30 Draft for comment D63/10695 ISBN 0 580 34541 6 Foreword This BritishStandard has been prepared to cover the requirements of aircraft ca
3、bin altimeters. The optimum accuracy specified for the instruments is related to the cabin altitude and temperature ranges of typical transport aircraft. 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
4、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 pressure within the cabin is adequate for the well-being of the passengers and crew. The standard requires reference to the following BritishStandards:
5、BS2G100, General requirements for electrical equipment and indicating instruments for aircraft. BSG101, General requirements for aircraft indicators: 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 me
6、tres is given inAppendix B. More accurate conversions should be based on the tables in BS350, “Conversion factors and tables”. 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. Complian
7、ce with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated
8、. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSG190:1964 BSI 02-2000 i Contents Page Foreword Inside front cover 1 Scope 1 Section 1. General requirements 2 General construction 1 Section 2. Particular requiremen
9、ts 3 Construction 1 4 Calibration 1 Section 3. Tests 5 General 1 Type tests 6 Ranging and accuracy test 2 7 Hysteresis test 2 8 Friction test 2 9 Position test 3 10 Temperature tests 3 11 Overload tests 3 12 Vibration test 3 13 Acceleration test 3 14 Climatic test 3 15 Waterproofness test 3 Producti
10、on routine test 16 Ranging and accuracy, hysteresis, friction, position and overload tests 3 Production quality test 17 Temperature and resonance tests 3 Appendix A Serviceability tests 4 Appendix B Conversion of British to metric units 4 Table 1 Permissible errors for Grade I instruments 2 Table 2
11、Permissible errors for grade II instruments 2 Table 3 Hysteresis tolerances 2 Table 4 Friction tolerances 2ii blankBSG190:1964 BSI 02-2000 1 1 Scope This BritishStandard specifies the general design requirements and test procedures for two grades of pressure cabin altimeters for aircraft: Grade I: f
12、or use with the pressurization control system, having a range of 2000ft to+20000ft. Grade II: for use by the pilot, having a range of 2000ft to+30000ft. Section 1. General requirements 2 General construction a) The design and construction of the instrument shall comply with the relevant requirements
13、 of BS2G100 and BSG101. b) The preferred case sizes, as shown in BSG101, are: Grade I: Type3, Type5 and Type8. Grade II: Type2, Type4 and Type7. Section 2. Particular requirements 3 Construction a) The instrument shall contain an absolute pressure measuring mechanism driving a single pointer. b) In
14、order to withstand cabin pressurization whilst the aircraft is on the ground, the instruments shall be capable of withstanding an absolute pressure of2000millibars (approximately two atmospheres) or, for Grade I instruments, any lower overload pressure quoted in the individual specification, with a
15、minimum of1129millibars(3000ft). NOTEIf Grade I instruments are declared to an overload pressure of less than2000millibars, 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
16、maintenance instructions. c) The instrument shall be capable of withstanding a pressure equivalent to an altitude10000feet 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
17、it satisfies the requirements of BS2G100-2 in respect of Grade B drip proof equipment. e) The dial of Grade I instruments shall be marked at intervals of2000ft with subdivisions at1000 and500ft intervals. f) The dial of Grade II instruments shall be marked at5000ft intervals with subdivisions at1000
18、ft intervals. g) The scale of Grade I instruments may extend over360degrees so that the zero height and20000ft positions are coincident at the top vertical position, or the scale may subtend less than360degrees. In either case stops shall be fitted to ensure that at altitudes above20000ft the pointe
19、r does not go above/the20000ft 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 BSG101. j) The instruments shall be capable of operation down to2000ft(1088.7millibars) and the
20、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 Document7488, May1954. Section 3. Tests 5 General a) Tests shall be made to prove compliance with all the requirem
21、ents of this BritishStandard. 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 be made on all
22、 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 this BritishSta
23、ndard are indicated in Appendix A. c) Vibration not exceeding0.2g shall be applied to the instruments during the performance tests, except the friction test specified in Clause8, to remove the effects of friction. NOTEVibration of this order is attainable with a total amplitude of0.04mm and a freque
24、ncy of50c/s.BSG190:1964 2 BSI 02-2000 d) No pressure cycling or exercising other than that produced by normal variation of terrestial barometric pressure shall be applied to the instruments for a period of not less than16hours before the ranging tests are performed. e) Readings taken from barometers
25、 used to test the altimeters shall be corrected for latitude and temperature. f) Unless otherwise specified, tests shall be made at a temperature of20 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 di
26、al upright and in a vertical plane, the errors shall not exceed the amounts specified inTable 1 or Table 2, as appropriate, when tested with pressure increasing and decreasing at a nominal rate of1000ft/min. Table 2 Permissible errors for grade II instruments 7 Hysteresis test The hysteresis as dete
27、rmined from the errors at the same barometric pressure, with the pressure decreasing and increasing in the ranging test, shall not exceed the limits specified inTable 3. Table 3 Hysteresis tolerances 8 Friction test At three approximately equally spaced increments of the dial, the pointer shall be b
28、rought to the desired reading and then held constant, the instrument being carefully isolated from vibration. Two readings shall 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 be
29、tween the two readings shall not exceed the tolerances specified inTable 4. This test may be combined with the ranging test but in any event shall be performed with both increasing and decreasing pressure. Table 4 Friction tolerances Height Pressure Permissible errors ft 2000 0 2000 3000 4000 6000 7
30、000 8000 10000 12000 14000 16000 18000 20000 millibars 1088.7 1013.25 942.13 908.12 875.10 811.99 781.85 752.62 696.81 644.41 595.24 549.15 506.00 465.63 ft+and 250 150 150 100 100 100 100 200 300 300 300 400 500 500 Height Pressure Permissible errors ft 2000 0 5000 10000 15000 20000 25000 30000 mil
31、libars 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 Height Permissible error Grade I instruments Grade II instruments ft 0 to10000 above10000 ft 150 300 ft 250 500 Height Tolerance Grade I instruments Grade II instruments ft 0 to10000 above10000 ft
32、100 200 ft 200 400BSG190:1964 BSI 02-2000 3 9 Position test The change in reading shall not exceed100feet when the instrument is tilted90 in any direction from the normal position. 10 Temperature tests a) The instrument shall be tested over the range0 C to+40 C and the errors shall not exceed those
33、quoted inTable 1 orTable 2, as appropriate. b) The instrument shall be tested at20 C and+50 C and the errors shall not exceed twice those quoted inTable 1 orTable 2, as appropriate. c) The instrument shall not be deranged by being subjected to temperatures of40 C and+70 C. After this test the instru
34、ment shall comply with the requirements of Clauses6, 7 and8 of this standard. 11 Overload tests a) Positive pressure. The instrument shall be subjected to an absolute pressure of2000millibars, or for Grade I instruments to the declared overload pressure, for five minutes. Immediately following this
35、test the tolerances specified inTable 1 orTable 2, as appropriate, shall not be exceeded by100feet; when retested within16 hours the tolerances shall be as specified inTable 1 orTable 2, as appropriate. b) Negative pressure. The instrument shall be subjected for five minutes to a pressure equivalent
36、 to an altitude10000feet higher than the maximum calibrated range of the instrument. The calibration shall be checked immediately afterwards at20000ft,10000ft and0ft and shall be within the tolerances ofTable 1 or Table 2, as appropriate. 12 Vibration test The instrument, without vibration mountings
37、, shall be subjected to vibration tests in accordance with BS2G100-2, as required by the individual specification. 13 Acceleration test The instrument shall be subjected to acceleration tests in accordance with BS2G100-2, as required by the individual specification. 14 Climatic test The instrument s
38、hall be subjected to the tests specified for climatic Class2 equipment in BS2G100-2. 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 ranging and accuracy, hysteresis and friction tests at the following altitudes: The indicated
39、 altitudes shall be within the appropriate tolerances shown inTable 1 toTable 4. 15 Waterproofness test The instrument shall be subjected to the drip test specified in BS2G100-2. Production routine tests 16 Ranging and accuracy, hysteresis, friction, position and overload tests Each instrument shall
40、 satisfactorily fulfil the requirements of the tests specified in Clauses6, 7, 8, 9 and11. Production quality tests 17 Temperature and resonance tests Sample instruments, selected as specified in the individual specification, shall satisfactorily fulfil the requirements of the tests specified in Cla
41、uses10 and12, except that for the purposes of the test in Clause12 only the requirements of BS2G100-2 for the resonance search test shall apply. 0ft 4000ft 8000ft 20000ft.BSG190:1964 4 BSI 02-2000 Appendix A Serviceability tests The minimum tests recommended to verify the serviceability of instrumen
42、ts manufactured in compliance with this BritishStandard are as follows: 1) Ranging and accuracy test (Clause6) at the following test points: 2) Friction Test (Clause8). Appendix B Conversion of British to metric units Approximate metric equivalents of the heights quoted in this BritishStandard are s
43、hown in the following table. More accurate conversions should be based on the tables in BS350. Grade I instruments Grade II instruments 0ft 0ft 6000ft 5000ft 10000ft 10000ft 20000ft 20000ft 30000ft ft m ft m 100 150 200 250 300 400 500 600 1000 2000 3000 4000 5000 30.5 45.7 61.0 76.2 91.4 121.9 152.
44、4 182.9 304.8 610.0 914.4 1219.2 1524.0 6000 7000 8000 10000 12000 14000 15000 16000 18000 20000 25000 30000 1828.0 2133.6 2438.4 3048.0 3657.6 4267.2 4572.0 4876.8 5486.4 6096.0 7620.0 9144.0blankBSG190:1964 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independ
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