1、- MIL-L-25467D h2 7977706 0305444 7 m MIL-L-25467D 12 July 1977 Superseding 29 May 1964 MIL-L-25467C MILITARY SPECIFICATION LIGHTING, INTEGRAL, RED, AIRCRAFT INSTRUMENT, GENERAL SPECIFICATION FOR This specification is approved for use by all Depart -. ments and Agencies of the Department of Defense.
2、 1. SCOPE * 1.1 This specificati0n:covers the general requirements for a 5-volt incandescent or 115 volt electroluminescent illuminating system for red integrally lighted aircraft instruments. This specification defines the requirements and test procedure applicable to the lighting system for aircra
3、ft instruments when referenced in an instrument specificatign; 2. APPLICABLE DOCUMENTS 2.1 - The following documents, of the issue in effect on dite of invitation for bids, form a part of. this specification to the extent specified herein: * SPECIFICATIONS Military MIL-C- 14806 Coating, Reflection R
4、educing, for Instrument Cover GIass and Lighting Wedges MIL-C-25050 Colors, Aeronautical Lights and Lighting Equip- ment, General Requirements for MIL-C-81774 Control Panel, Aircraft, General Requirements for Beneficial comments (recommendations, additions, deletions). and any pertinent data which m
5、ay be of use in improving this document shold be addressed eo: Engineering Specifications and Standards Department (Code 93), Naval Air Engineering Center, Lakehurst, NJ 08733, by using the self-addressed Standardization.Document Improvement Proposal (DD- Form 1426) appearing at the end of this docu
6、ment or by letter. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-L-25467D STANDARDS Federal PED-STD-595 Colors Military MS24367 Lamp, Incandescent, Miniature Integral Lighting MS24515 Lamp, Sub-Miniature BIS25237 Lamp, Incadescent, Single Conta
7、ct Midget Flanged Base (T-1-3/4 Bulb) MS27569 Lamp, Incandescent, Miniature Integral Lighting, T-1-314 Size MS27570 Lamp, Incandescent, Miniature Integral Lighting, T-1-114 Size MS27571 Lamp, Incandescent, Miniature Integral Lighting, T-1 Size (Copies of specifications, standards, drawrtngs, and pub
8、lications required by contractors in connection with specific procurement functions should be obtained from the procuring activity or as directed by the contracting officer.) 3. REQUIREMENTS 3.1 General. The requirements of this specification are applicable as the lighting system requirements .of th
9、e applicable instrument specification. (See 42) 3.2 Materials- Materials used in the lighting systems shall be of the type to withstand the service, functional and environmental conditions specified by the applicable instrument specification. 3*3 Design and construction. the achi 3.31 Design. The li
10、ghting system shall be so designed that lighted portion of the display will be held to the minimum required to .eve the optimum presentation of information. Light emitted from the edge of a coverglass or wedge, or both, and light emitted from around the dial (halo-effect) shall not be visible when v
11、iewed from any point on a 36- inch line determlned by the intersection of a plane parallel to and 18 inches from the front surface of the instrument coverglass and a horizontal plane 12 inches above the geometric center of the instrument coverglass (See Figure 1). The middle of the line shall be the
12、 point determined by the intersection of the 36-inch line and a vertical plane perpendicular to the instrument coverglass and passing through the geometric center of the display (See Figure 1). Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-L-25
13、467D 62 m 7777906 0105q46 O m MIL-L-25467D HORIZONTAL PLANE 36-INCH LINE T MIDDLE OF INSTRUMENT 12 N. I I 36 INCH LINE - FRONT SURFACE PLANE PARALLEL GEOMETRIC CENTER OF COVERGLASS TO FRONT SURFACE OF DISPLAY OF COVERGLASS 18 IN. m VERTICAL PLANE SIDE VIEW FRONT VIEW FIGURE 1. * 3.3.2 Construction.
14、The lighting system shall be so con- structed that the light sources are contained within the instrument enclo- sure. The coverglass, when used as part of the lighting system, shall not interfere with the visibility of any portion of the dial or scale (for incandescent lighting a minimum of two (2)
15、lamps shall be used for each instrument), No one portion of the indicia shall depend solely on one incandescent lamp for its illumination. No portion of the illuminated display shall be decreased by more than 60 percent of its original bright- ness when a lamp is deenergized or fails in service. The
16、 lighting system shall. be built to last the normal life of the instrument and shall in no way interfere with the correct operation of the instrument. Otherwise, the method best suited for the instrument involved may be used, provided it meets the requirements specified herein. * 3.3*3 Coverglass 2n
17、d wedges. All surfaces of the instrument coverglass and any other transparent element between the coverglass and dial, such as a lighting wedge shall be treated with a reflection reducing coating conforming to MIL-C-14806. For wedge assemblies, alignment marks shall be placed on the edge of the wedg
18、e-coverglass to facilitate alignment of the coverglass with the bezel. 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-L-25467D 3.3.4 Lamps. When any helium is used in the filling medium of an hermetically sealed instrument, only MS27569, MS275
19、70-8515AS15, or MS27571-6809AS15 lamps shall be used. If helium is not used or if a non- hermetically sealed case is used then MS25237-328AS10, MS24367-715AS15 or MS24515-710AS15 lamps may be used. For any one instrument the same type of lamp shall be used. If an electroluminescent light source is c
20、hosen, a lamp capchle of providing 100 hours of life to half of initial brightness shall be used. Initial brightness shall be defined as that brightness measured after an initial period of 100 hours. 3.3.5 Lamp location. Where practicable lamps shall be replaceable without opening the instrument cas
21、e or using tools. Replace- ment units shall not protrude beyond the surface of the instrument case. In-flight replacement is not intended, Where the applicable instrument specification requires hermetic sealing, the lamps need not be contained within the seal. 3.3.6 Lamp circuit. Unless otherwise sp
22、ecified by the procuring activity, the lamp circuit shall be designed to operate from a 5.00 0.1Ov or a 115 2V, 400 2 20 Hz power source. All lamps shall be connected in parallel. The lamp circuit may use a ground return within the instrument except in applications where a case ground return would b
23、e harmful to the correct operation of the instrument. In all applications, the lamp circuit shall terminate in two pins used solely for the lamp circuit. When a case ground return is used, the case grounded portion of the lighting system shall be clearly marked on the instrument wiring diagram to in
24、sure proper connection to the grounded side of the power supply. Externally adjustable resistors may be used to balance lighting between instruments. 3.3.6.1 Dielectric. The lamp circuit shall be able to withstand 5OOV plus twice the lamp circuit design voltage of 400 Hz for one minute between each
25、terminal and ground and between the lighting terminals with lamps removed. If the lamp circuit uses a ground return, this requirement shall be compiled with before the circuit is connected to ground. 3.3.6,2 Electric connector. Unless otherwise specified by the procuring activity, the electrical cir
26、cuit for the lighting system shall terminate in the electric connector used or other electrical terminals to the indicator. In the event the instrument does not require an electric connector except for the lighting circuit, a connector suitable for attachment to the plug assembly shall be as specifi
27、ed in the detail specification. A suitable cap shall be provided to protect the connector during shipment and storage. Unless sthexwise specified by the procuring activity, the connector shall be located on the back of the instrument case. A mating connector plug assembly with approximately 3 feet o
28、f wire attached to the lighting terminals shall be furnished for qualification or preproduction test purposes. 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-7 MIL-L-25467D h2 U 7799706 0305Y48 4 m MIL-L-25467D 3,3.,7 Color. AU thtz light emitted
29、by the lamps shall be converted to aviation. red -as specified in MIL-C-25050, except that the color shall not be paler or yellower than the Instrument Panel Lighting Limit Filter National Bureau of Standards (NBS) No. 3215 * 3.3.8 Brightness I When 5.00 ,+ O. 10V or 115 2 2V, 400 f 20 Hz are applie
30、d to the lighting terminals, whichever is applicable, the light intensity and the light: distribution of the lighting system shall be such that the brightness of .the presentation shall eonform to Table .I., For any single display, the average brightness of. the pointer ad. lubber lines shall always
31、 be greater than the average of the display markfngs; In no case shall the brightness of the pointer and.lubber line exceed 1.7 foot- .- - lamberts. . - TABLE I. Photometric. Brightrre.ss . . - * Incandescent : Daylight Color Lighting System Brightnesa (Foot-Lamberts). White - (Markhgs) , . . 1-0 +,
32、 0.5 White - (Pointer and . - . Lubber Lines) 1.2 f.0.5 - Transilluminated Gray - (Background) . . . 0.6 .-amherfin the upper half ofth instrument. The upper half and lower half of the instrument; are separated by a-horizontal plane containing the instrument centerline when the instrument face is in
33、 the vertical upr.ight position. Where-the instrument coverglass is square or rectangular, a sheet of white paper shall be placed perpendicular to the coverglass and on any line .parallel to the top edge of the coverglass. The brightness of any point looking down on the paper shall not exceed 1.50 f
34、oot-lamberts and on any ponc looking up on the paper shall not exceed 0,ZO foot-lambert. The sheet df white paper used.in.the ab.ove measurements shall be neutral, diffusing, and have a reflectance of 85 5 percent. Th measurement of stray light shall be edeat a point 0.5 inch in front of the instrum
35、ent Coverglass. . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-L-25467D 3.3.10 Dial visibility. The lighting system shall in no way restrict the visibility of any graduations, numerals, pointers, and other specific markings, when viewed from t
36、he line defined in 3.3.1. 3.3.11 Knobs and lettering. Unless otherwise specified in the applicable instrument specification, all indicia associated with instrument knob positions and all lettering on the instrument face shall be Illuminated. !Che brightness range shall be as specified in MIL-C-81774
37、. 3.3.12 Indicia. The presentation may be any combination of white, black, or gray, as specified in the applicable instrument specifi- cation. Unless otherwise specified in the applicable instrument specifi- cation, the colors shall conform to Table II, TABLE II. Colors 37875 Black . . . . . . 37038
38、 Grav 36440 3.3.13 Contrast. Contrast between the white and black portions of the indicator scale shall be 12 or greater. Contrast between the gray and black portions of the indicator scale shall be 5 or greater. Contrast “C“ is defined as: B2 - BI BI C= Where B2 is the brightness of the gray or whi
39、te and E I the brightness of the black portions of the instrument scale. Contrast measurements shall be made under uniform, diffuse illumination. For contrast qualification and preproducton tests, one sample of all portions of the presentation behind the coverglass (dials, pointers, tapes, counters,
40、 etc.) shall be furnished. 4. QUALIIY ASSURANCE PROVISIONS 4.1 Contr.actots responsibility. The supplier is responsible for the performance of all inspection requirements as specified herein. Except as otherwise specified, the supplier may utilize his own or any other inspection facilities and servi
41、ces acceptable to the Government. Inspection records of the examination and tests shall be kept complete and availabl.8 to the Government as specified in the contract or order. The Government reserves the right to perform any of the inspections set forth in the specification where such inspections a
42、re deemed necessary to assure supplies and services conform to prescribed requirements. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-L-25Llb7D 62 U 7777706 OLO5Ll50 2 U MIL-L-25467D * 4.2 Classification of tests. All the tests specified in T
43、est Methods (4.5) constitute the lighting system requirements of the qualification or first article tests, whichever is applicable, and acceptance tests of the applicable instrument specification. 4.3 Tests. The lighting system tests shall consist of the individual and sampling tests of this specifi
44、cation. * 4.3.1 Individual tests. Each instrument lighting system shall be subject-ed to the following tests: a. Examination of product (4.5 1) b. Operation (4.5.2) 4.3.2 Sampling tests. * 4.3.2.1 Sampling plan A. One instrument selected at random from each lot of 100 or less produced on the contrac
45、t or order shall be subjected to the following tests: a. Individual tests (4.3.1) b. Light (4.5.3) * 4.3.2.2 Sampling plan B. Unless otherwise specified, two instruments selected at random from the first 10 items of the contract or order shall be subjected to the following tests: a. Sampling plan A
46、(4.3.2.1) b. Contrast (4.5.4) c. Lamp circuit (4.5.5) d. Dielectric (4.5.6) e. Life (4.5.7) * 4.3.3 Rejection and retest. When one item selected from a production run fails t6 meet the requirements of the specification, no items still on hand or later produced will be accepted until the extent and c
47、ause of failure are determined and corrected. 4,3.3.1 Ind-ividual tests may continue. For operational reasons, individual tests may be continued pending the investigation of a sampling test failure. But final acceptance of items on hand or later produced will not be made until it is determined that
48、items meet all the requirements of this specification. 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-L-25467D 4. 3.4 Defects in items already accepted. The investigation of a test failure could indicate that- defects may exist in items alread
49、y accepted. If so, the contractor shall fully advise the procuring activity of all defects likely to be found and methods of correcting them. 4.4 Test conditions 4.4.1 Atmqspheric conditions. Unless otherwise specified, tests required by this specification sh$l beemade at atmospheric pressure of 28 to 32 in. Hg, a temperature of 25 2 10 C, and a relative humidity of 80 percent or less. 404.2 Environmental conditions. Wherev
