1、BRITISH STANDARD AEROSPACE SERIES BS3G101: 1987 (Superseding BS2G101) Specification for General requirements for mechanical and electromechanical aircraft indicators UDC 629.7.054874BS3G101:1987 This BritishStandard, having been prepared under the directionof the Aerospace Standards Committee, was p
2、ublished under the authorityofthe Board of BSI andcomes into effect on 27February1987 BSI04-2000 The following BSI references relate to the work on this standard: Committee reference ACE/30 Draft for comment84/78651 DC ISBN 0 580 14955 2 Committees responsible The preparation of this BritishStandard
3、 was entrusted by the Aerospace Standards Committee (ACE/-) to Technical Committee ACE/30, upon which the following bodies were represented: Civil Aviation Authority (Airworthiness Division) GAMBICA (BEAMA Ltd.) Ministry of Defence Society of British Aerospace Companies Limited Amendments issued sin
4、ce publication Amd. No. Date of issue CommentsBS3G101:1987 BSI 04-2000 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Cases 1 3 Connections 1 4 Mounting attitude 2 5 Indicator movements 2 6 Presentation 2 7 Cover glasses and windows 4 8 Integral lighting 4 9 Lumine
5、scent and fluorescent markings 4 10 Self-test 5 Figure 1 Dimensions for flangeless round indicator cases 6 Figure 2 Dimensions for flangeless round indicator cases, panel cutouts 7 Figure 3 Standard dimensions for flangeless square and rectangular cases 8 Figure 4 Flangeless square indicator cases,2
6、in(50.8mm) 10 Figure 5 Flangeless square and rectangular cases, cutouts 11 Figure 6 Standard mooring plates, flangeless, square and rectangular cases 13 Figure 7 Standard adaptor plates, flangeless, square and rectangular cases 15 Figure 8 Mounting arrangement for flangeless squareandrectangularindi
7、cator cases 17 Figure 9 Recesses for pitot pressure connections 18 Figure 10 Recesses for static pressure connections 19 Table 1 Types of indicator case 1 Publications referred to Inside back coverBS3G101:1987 ii BSI 04-2000 Foreword This revision of BS2G101:1975 has been prepared under the directio
8、n of the Aerospace Standards Committee to align the general requirements for aircraft indicators with ISO268:1980 published by the International Organization for Standardization (ISO). The general requirements stipulated are for use in conjunction with G series BritishStandards for specific aircraft
9、 indicator types. As in the case of previous editions, the requirements of this standard will not be applied retrospectively. Imperial units are used in this standard to maintain compatibility with existing aircraft practice; metric dimensions are given in parentheses. A British Standard does not pu
10、rport 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 inside front
11、 cover, pagesi andii, pages1 to20, 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.BS3G101:1987 BSI 04-2000 1 1 Scope This BritishStandard spec
12、ifies requirements which are generally applicable to mechanical and electromechanical indicators for use in aircraft. It is to be read in conjunction with specifications for individual indicators and the relevant requirements of BS3G100. For the purpose of this standard, an indicator is regarded as
13、a unit primarily concerned with the visual display of information. NOTE 1The titles of the publications referred to in this standard are listed on the inside back cover. NOTE 2The latest revision of an aerospace standard is indicated by a prefix number. 2 Cases 2.1 The finished indicator cases shall
14、 be of the types given in Table 1, unless specified otherwise in the contract or order. Table 1 Types of indicator case 2.2 The mounting details for the front area of the indicator case and mounting shall comply with Figure 1 to Figure 5 as appropriate (seeTable 1). NOTE 1To allow physical interchan
15、geability of panel indicators, a range of preferred mounting dimensions has been established. NOTE 2The individual specification for the indicator, referred to in this Part of BS3G101 as “the individual specification”, states all the dimensions for the case. NOTE 3Information on panel cutouts is giv
16、en for each type. NOTE 4The two methods of mounting most commonly used are as follows. a) Clamp mounting, with the indicator secured in the operating position by a clamp mounted on the rear face of the indicator panel. For this arrangement access to the rear of the panel is not required when the ind
17、icator is fixed, as the clamp arrangement is operated from the front of the panel. The clamp method of mounting is also used by circular and square indicators. It is particularly important with this type of indicator to ensure that the surface around which the clamp fits is of uniform dimension and
18、of adequate strength to retain rigidity of mounting. b) Clamp mounting, with mooring plate and/or optional adaptor plate as shown in Figure 6, Figure 7 and Figure 8. 2.3 Any limitation in the use of a mounting for which the indicator has been declared shall be stated by the manufacturer. During vibr
19、ation and acceleration testing the declared mounting shall be used. 2.4 An indicator case with electrical connections shall be earthed through a connector terminal pin or bonding point. Unless otherwise required by the individual specification, no internal electrical circuit shall be returned via th
20、is case/earth bonding connection. The current-carrying capacity of the case earthing wire shall be greater than the current-carrying capacity of the associated airframe wiring. 2.5 The design and construction of the indicator case shall be such that the indicators specified performance is unaffected
21、 when the indicator, installed in accordance with the relevant declarations, is subjected to the test for drip-proof equipment in accordance with BS3G100-2, and to tests for resistance to other fluids, as required by the individual specification. 2.6 The legibility of the indicator shall not be affe
22、cted by any misting inside the glass under the conditions of use for which it is declared. 2.7 An indicator required by the individual specification to have an airtight or pressure-resisting case shall be capable of withstanding, without damage or leakage greater than that permitted by the individua
23、l specification, external pressures from100kPa (1000mbar) above that of the interior to20kPa (200mbar) below that of the interior, and there shall be no interference between the moving elements and the cover glass during and after the application of pressure. NOTEIndicators should not present a haza
24、rd due to implosion or explosion. 2.8 Where an indicator is vented to the surrounding atmosphere, the vent shall not affect the performance of the indicator. It shall be screened to prevent the ingress of sand and dust. The vent shall be protected against inadvertent closure and located at approxima
25、tely the lowest point connecting with the interior when the indicator is in the normal position. 2.9 Hermetically sealed instruments shall be used only where essential for performance lifting requirements. 2.10 The sealing of the indicator shall not preclude easy access to its interior for servicing
26、 purposes. 3 Connections 3.1 Pressure connections 3.1.1 Where an indicator has more than one pressure connector, the connectors shall be of different sizes. 3.1.2 The tapped holes of the pitot and static connections shall be indelibly identified. Type Figure Flangeless round Flangeless square and re
27、ctangular Flangeless square2in (50.8mm) Figure 1 andFigure 2 Figure 3 andFigure 5 Figure 4BS3G101:1987 2 BSI 04-2000 3.1.3 Where indicators are supplied without adaptors, the female recesses shall comply with the following requirements. a) Recesses for pitot connections shall be in accordance with F
28、igure 9. b) Recesses for static connections shall be in accordance with Figure 10. c) Recesses for connections to pressure-measuring indicators other than pitotstatic instruments shall be in accordance with Figure 9. d) The connections shall be unobstructed to a depth as given in Figure 9 and Figure
29、 10. e) The connections shall be securely attached to the case and shall be capable of withstanding a torque of200lbfin (22.6Nm) when mounted on the panel. For test purposes the case shall be mounted on a suitable plate. The plate shall be firmly clamped and the torque gradually applied to the conne
30、ctions. NOTEThe boss shown in Figure 9 and Figure 10 is to provide clearance when banjo fittings are used; it should be omitted or modified if so required by the individual specification. 3.2 Electrical connections 3.2.1 It shall be impossible for a multi-pin electrical connector used on an indicato
31、r to be mated incorrectly with the complementary cable-mounted connector. 3.2.2 Where an indicator has more than one multi-pin electrical connector, the design of the connectors shall be such as to make incorrect connections impossible. 4 Mounting attitude 4.1 The indicator shall be suitable for mou
32、nting in any attitude, and shall comply with the accuracy requirements in any attitude. Any limitations on mounting attitudes shall be declared by the manufacturer. 4.2 The individual specification shall state the normal mounting attitude at which the indicator is to be calibrated. 5 Indicator movem
33、ents 5.1 Indicator movements shall be securely fixed to the body of the indicator in such a manner that any distortion by connection or mounting of the indicator does not affect the accuracy of indication. 5.2 The design of an indicator and the form of its input information shall ensure that each va
34、lue of the input parameter results in a unique indicator reading. 5.3 Stops shall be fitted to indicator movements where otherwise the display would be able to move beyond the end of the scale to positions that result in erroneous readings. These stops shall be operative above the maximum and/or bel
35、ow the minimum scale graduations respectively, but shall be such that the direction from which the display is deflected is still apparent. 5.4 Indicators shall accurately and smoothly follow changes of input at rates of change up to maximum conditions defined in the individual specification. 5.5 Poi
36、nter oscillations and display fluctuations which result from environmental conditions or noisy input information shall be suppressed. 5.6 Indicator movements shall not be damaged or deranged by sudden or extreme changes of input information which are experienced at switch-on or during ground tests.
37、5.7 The indicator shall be designed to have minimum power consumption. NOTEIt should be a design aim not to exceed0.30W/in 3 (18.3kW/m 3 ) or0.20W/in 2(0.31kW/m 2 ) of external surface area. Heat dissipation should be measured for the maximum duty cycle during normal operation, including integral li
38、ghting. 6 Presentation 6.1 General 6.1.1 The indicator shall present the required information concisely and with a degree of precision compatible with the indication required and with the sensitivity of the movement. The data presented shall be prime, that is, no further operation upon it shall be n
39、ecessary apart from simple factoring. 6.1.2 The design and purpose of the display shall be clear and unambiguous and such that it cannot be confused with other types of display likely to be used with it. In particular, for scales in excess of360 with a single pointer, means shall be provided to prev
40、ent ambiguity. Single channel, concentric, multi-pointer displays (for example, three-pointer altimeters) shall be avoided. 6.1.3 Indicators shall be designed so that parallax effects and tunnel (masking) effects do not interfere with reading of the indicator, to the degree of precision appropriate
41、to the function(s) being displayed, when viewed from angles up to40 to a perpendicular axis through the centre of the display face. 6.1.4 Manufacturers name, symbol or part number or other information not essential to the function(s) being displayed shall be unobtrusive if marked on dial faces or in
42、strument bezels. 6.1.5 Where a display has both a pointer and counter presentation, masking of the counters by the pointer shall be kept to a minimum.BS3G101:1987 BSI 04-2000 3 6.1.6 Where the indicator is luminous, the treated area shall be kept to a minimum compatible with ease of reading (see9.3.
43、2). 6.2 Scales and counters 6.2.1 Figures and graduations shall be restricted to the minimum number compatible with the accuracy of reading required. If the purchaser does not state requirements for coloured markings, markings shall be white on black background. All coatings used shall have a matt f
44、inish. NOTEThe colour specification for markings or other areas of colour is a matter for agreement between the purchaser and the manufacturer. 6.2.2 For circular scale displays, the values shall increase in a clockwise direction. For strip (straightscale) displays, the values shall increase from bo
45、ttom to top or from left to right. 6.2.3 Where non-linear scales are used, linear interpolation between graduations shall not result in errors greater than the specified instrument accuracies. Indicators with individually calibrated scales and having the same part number shall have identical scale n
46、umbers and divisions, and the working range shall be geometrically similar. Over those parts of the scale which are operationally important, graduations shall represent equal increments of indicated quantity. The tolerances governing these instrument accuracies shall be as given in the individual sp
47、ecification. 6.2.4 Sufficient figures shall be marked on the dial to minimize the possibility of misreading by a whole scale division. Those numerals, located against major scale graduations, shall increase in single units, in twos, in fives or in decimal equivalents. 6.2.5 The preferred smallest sc
48、ale interval which is marked but has no numeral against it shall represent one, or two or five units, or any decimal fraction of such units. 6.2.6 If a rotating-drum digital display is incorporated in the presentation, the higher digit shall appear above the lower digit, that is the digits shall mov
49、e downwards for increasing values. Counter indicators shall be provided with a means of ensuring that a complete number is always visible and of identifying the direction of increase or decrease of the value indicated, either by the provision of an aperture large enough for adjacent numeral(s) to be seen or by other means. 6.3 Pointers and indices 6.3.1 The shape and size of pointers shall be such as to enable the indication to be readily appreciated to meet required operational conditions. NOTEWhere speed of reading is essential, it is preferable tha
