1、BRITISH STANDARD AEROSPACE SERIES BS2G191: 1988 Specification for Lighting for aircraft indicators using integral filament lamps UDC 629.7.048.8:681.2.085:621.326BS2G191:1988 This BritishStandard, having been prepared under the directionof the Aerospace Standards Committee, was published under the a
2、uthority ofthe Executive Board and comesinto effect on 29February1988 BSI04-2000 The following BSI references relate to the work on this standard: Committee referenceACE/30 Draft for comment86/78583DC ISBN 0 580 16301 6 Committees responsible The preparation of this BritishStandard was entrusted by
3、the Aerospace Standards Committee (ACE/-) to Technical Committee ACE/30, upon which the following bodies were represented: Civil Aviation Authority (Airworthiness Division) Ministry of Defence Society of British Aerospace Companies Limited Amendments issued since publication Amd. No. Date of issue C
4、ommentsBS2G191:1988 BSI 04-2000 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definition 1 3 Supply voltage 1 4 Colour of light source 1 5 Measurements 1 6 Luminance 1 7 Warning flags 1 8 Stray light 1 9 Markings to background contrast ratio by daylight 2 10 Relia
5、bility 2 11 Safety electrical connections 2 Figure 1 Positioning of indicator for stray light tests 3 Publications referred to Inside back coverBS2G191:1988 ii BSI 04-2000 Foreword This BritishStandard has been prepared under the direction of the Aerospace Standards Committee and is a revision of BS
6、G191:1965 which is withdrawn. This revision brings the standard into line with modern instrument lighting practice, and updates the references. Aircraft indicators produced in accordance with this standard have to meet the requirements of individual aircraft applications specified by the aircraft ma
7、nufacturer or the aircraft operator. For each application, the indicator manufacturer produces an individual indicator specification which will specify the lighting requirement and which is called up in the appropriate clauses of this standard. The standard has been based on the latest knowledge and
8、 experience of manufacturers of instrument integral lighting systems. 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 immu
9、nity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4, 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 ame
10、ndment table on the inside front cover.BS2G191:1988 BSI 04-2000 1 1Scope This BritishStandard specifies requirements for the integral lighting of aircraft panel indicators. It sets out limits of luminance which should be met so that instruments grouped on an aircraft instrument panel may have an acc
11、eptable uniformity of luminance. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definition For the purposes of this BritishStandard the following definition applies. integral lighting a system of lighting wholly contained within the case of an
12、aircraft indicator. It does not include warning lights or lighting systems consisting wholly or partly of lamps projecting from the front of the indicator in such a way as to provide local floodlighting from outside the indicator 3 Supply voltage The lighting system shall be designed to operate with
13、 a maximum supply voltage of5.0Vr.m.s., or5.0Vd.c. 4 Colour of light source The colour of the light shall be either red or white. NOTEIt is preferred that only one of these colours should be used in any one instrument. The colour of the light, with a supply of5.0V, shall be as specified in BS1376, c
14、lassA colours. 5 Measurements 5.1 A spot photometer or a comparable alternative, colour matched to the lighting colour specified and calibrated in candelas per square metre or foot-lamberts, shall be used to measure the brightness of the individual scale markings, pointers and characters. The same p
15、hotometer may be used to check the brightness of the background. 5.2 When the final instrument is to be fitted with a cover glass reflection-reducing coating to comply with BSG211, this type of glass shall be fitted for all brightness tests. 6 Luminance NOTE 1The requirements of this clause apply to
16、 all black and white areas of the indicator, including any essential lettering. NOTE 2Any special luminance requirements for coloured areas of the display should be stated in the individual indicator specification. In the absence of all external sources of illumination, the luminance of the indicato
17、r, measured in a direction within10 to the normal of the part of the dial being measured, shall comply with the following. a) For indicators with white lighting, at a supply voltage of2.7 0.05V: b) For indicators with red lighting, at a supply voltage of5.0V. 7 Warning flags Warning flags shall be v
18、isible when viewed under all lighting levels at which the indicator may be used. 8 Stray light NOTEThe requirements of this clause relate to instruments designed for mounting in panels within25 of the vertical position: the requirements for instruments for use in other positions shall be agreed with
19、 the manufacturer. The lighting system shall be designed to shield all lamps from direct view when the indicator is viewed from angles of up to60 either side of and above its centreline and up to30 below its centreline. The following tests shall be carried out with a supply voltage of5.0V, and with
20、the indicator situated on a neutral85% reflective surface. a) With the indicator dial in its normal orientation and with the mounting plane of the indicator case perpendicular to the surface see Figure 1(a), the maximum luminance measured on the surface shall not exceed23.98Cdm 2 (7.0ft-L) for white
21、 lighting and5.139Cdm 2 (1.5ft-L) for red lighting. +0 0.1 Part of indicator Luminance Cdm 2 (ft-L a ) Pointers, flags, counters, indices (inall positions) 0.856 to3.426 (0.25 to1.0) Dial markings 0.856 to2.570 (0.25 to0.75) Black areas Not more than0.171 (Not more than0.05) a 1ft-L=3.426 Cdm 2 Part
22、 of indicator Luminance Cdm 2 (ft-L) Pointers, flags, counters, indices (inall positions) 1.713 to6.852 (0.5 to2.0) Dial markings 1.713 to5.139 (0.5 to1.5) Black areas Not more than0.343 (Not more than0.1) +0 0.1 +0 0.1BS2G191:1988 2 BSI 04-2000 b) With the indicator dial rotated through90 in either
23、 direction from its normal orientation and perpendicular to the surface see Figure 1(b) and Figure 1(c), the maximum luminance measured on the surface above the centreline of the dial shall not exceed3.426Cdm 2 (1.0ft-L) for white lighting and0.685Cdm 2 (0.2ft-L) for red lighting. c) With the indica
24、tor dial rotated through180 from its normal orientation and perpendicular to the surface see Figure 1(d), the maximum luminance measured on the surface shall not exceed3.426Cdm 2 (1.0ft-L) for white lighting and0.685Cdm 2 (0.2ft-L) for red lighting. 9 Markings to background contrast ratio by dayligh
25、t The luminance contrast ratio between white areas and background areas of the instrument dial, viewed by day-light in the range of200 to90000lux 1)from any direction within10 normal to the instrument glass, shall be not less than13:1, where contrast ratio is defined as 10 Reliability 10.1 Life The
26、design of, and the components used in, integral lighting systems shall be of such a standard and quality that they do not impose a limit on the useful life of the indicator as specified in the individual specification for the indicator. Provision may be made for lamps to be changed with the indicato
27、r mounted in the operating position. Such provision shall not affect the reliability of the indicator. 10.2 Environmental conditions The integral lighting system shall be capable of functioning correctly under the full range of environmental conditions specified in the individual specification for t
28、he indicator. 10.3 Lamp failure The design of the lighting system shall be such that in the event of failure of a single lamp the indicator shall be capable of being read accurately. 11 Safety electrical connections 11.1 The lighting connections shall be either brought out on separate supply pins or
29、 as stated in the individual specification for the indicator. The lamps shall be directly connected in parallel to the supply pins without series resistors. No part of the lighting circuit within the instrument shall be connected to ground. 11.2 The insulation resistance between the lighting circuit
30、 and the indicator case shall comply with BS3G100-4.1.1. 1) 1foot candle (obsolete)=10.764lux. Luminance of white areas Luminance of background areas -BS2G191:1988 BSI 04-2000 3 Figure 1 Positioning of indicator for stray light tests (see clause7)4 blankBS2G191:1988 BSI 04-2000 Publications referred
31、 to BS1376, Specification for colours of light signals. BS3G100, Specification for general requirements for equipment for use in aircraft. BS3G100-4.1.1, Electrical insulation tests. BSG211, Specification for reflection-reducing coating of instrument windows and lighting wedges. BS2G191: 1988 BSI 38
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