1、MIL-L-27160C(USAF)3 March 1972 SupersedingMIL-L-7160B(USAF)16 Jul 1963MILITARY SPECIFICATIONLIGHTING, INSTRUMENT, INTEGRAL, WHITEGENERAL SPECIFICATION FOR1. SCOPE1.1 This specification covers the general requirements for a 5.0V illuminating system forintegrally white-lighted aircraft instruments usi
2、ng incandescent lamps as the light source.2. APPLICABLE DOCUMENTS2.1 The following documents, of this issue in effect on date of invitation for bids orrequest for proposal, form a part of this specification to the extent specified herein:SPECIFICATIONSMilitaryMIL-C-675 Coating of Glass Optical Eleme
3、nts (Anti-reflection)MIL-C-14806 Coating, Reflection Reducing, for Instrument Cover Glassesand Lighting WedgesSTANDARDSFederalFED-STD-595 ColorsMilitaryMS21376 Lamp Sub Miniature Helium Retardant Flange Base, T-1 SizeMS24367 Lamp, Incandescent - Miniature Integral LightingMS24515 Lamp - Sub Miniatur
4、eMS25237 Lamp, Incandescent, T-1 3/4 Bulb, Midget Flange BaseMS27569 Lamp, Incandescent - Miniature Integral Lighting, T-1 3/4 SizeMS27570 Lamp, Incandescent - Miniature Integral Lighting, T-1 1/4 SizeMS27571 Lamp, Incandescent - Miniature Integral Lighting, T-1 SizeProvided by IHSNot for ResaleNo r
5、eproduction or networking permitted without license from IHS-,-,-MIL-L-27160 (USAF)2(Copies of documents required by suppliers in connection with specific procurementfunctions should be obtained from the procuring activity or as directed by the contractingofficer.)3. REQUIREMENTS3.1 Qualification or
6、 preproduction. Qualification or preproduction provisions shall be asspecified in the applicable instrument specification.3.2 Materials. The instrument lighting system shall be of materials that will enable it towithstand the service, functional, and environmental conditions specified by the applica
7、bleinstrument specification.3.3 Design and construction. The lighting system shall be contained within the instrumentcase. A minimum of two lamps shall be used for each instrument. The lighting systemshall not interfere with the visibility of any portion of the dial or scale. No one portion ofthe di
8、splay shall depend upon one lamp for its illumination. The lighting system shall in noway interfere with correct operation of the instrument.3.3.1 Coverglass. The instrument coverglass and any other transparent element betweenthe coverglass and dial shall be coated with a reflection reducing film in
9、 accordance withMIL-C-675 or MIL-C-14806 as specified in the applicable instrument specification.3.3.2 Lamps. When any portion of helium is used in the filling medium of the instrument,only MS21376, MS27569, MS27570-8515AS15, MS27570-1191AS15, MS27571-6809AS15, or MS27571-6808AS15 lamps may be used.
10、 If helium is not used or if a non-hermetically sealed case is used, the MS25237-328AS10, MS24367-715AS15, MS24367-713AS15, MS24515-718AS15 lamps may be used in addition to the above lamps. Anylamp selected shall be used throughout the system.3.3.2.1 Lamp location. Lamps may be accessible either fro
11、m the outside of theinstrument or contained within the instrument case. Where practicable, lamps shall beremovable without opening the case. In-flight replacement will not be required. Whereapplicable instrument specification required hermetic sealing, lamps need not be containedwithin the seal.3.3.
12、2.2 Lamp circuit. The lamp circuit shall be designed to operate from a 5.0V 400-Hzpower system. All lamps shall be connected in parallel. In all applications, the circuit shallterminate in two pins which shall be used solely for the lamp circuit. Resistors ortransformers shall not be used within the
13、 instrument to change to voltage applied to thelamp terminals. (Wiring between the two lighting terminals on the connector and the lampsocket or terminals shall be of sufficient size to prevent any appreciable voltage drop in thewiring.)Provided by IHSNot for ResaleNo reproduction or networking perm
14、itted without license from IHS-,-,-MIL-L-27160 (USAF)33.3.2.2.1 Dielectric. The lamp circuit shall withstand 500V plus twice the lamp circuitdesign voltage at 60 Hz for one minute under the conditions specified in 4.5.7.3.3.3 Life and reliability. The lighting system shall be designed for a life of
15、1,000 hours orfor the period required by the applicable instrument specification, whichever is greater.Reliability shall be in accordance with the applicable detail specification.3.3.4 Color. The color of the white portions of the indicator display with 4.50 0.050Vapplied to the lighting terminals s
16、hall be x = 0.440 0.020 and y = 0.405 0.020 whenmeasured as specified herein.3.3.5 Brightness. When 4.50 0.050V are applied to the lighting terminals, the lightintensity and distribution shall be as follows:a. White areas: 1.00 0.50 foot-lambert. The average of all readings taken in thewhite areas s
17、hall be 1.00 0.30 foot-lamberts.b. Gray area: 0.60 0.30 foot-lambert.c. Black areas: 0.05 0.03 foot-lambert when reflected light (wedge and ring lighting) is used and 0.04 0.02 foot-lambert for refracted light (back lighting).d. Pointers, lubber lines, command bars, miniature airplane symbols deviat
18、ion bars, andother similar reference marks:1.20 0.50 foot-lambert. The average brightness of all of the (pointer) readings shall be 0.10 to 0.50 foot-lamberts higher than the average brightness of the (dial) white areas.e. Red areas: 1.00 0.50 foot-lambert.The brightness of other colors and the sele
19、ction of colors shall be governed by theirrelative brightness in daylight and shall be subject to the approval of the procuring activity.When no other guidance is available, the brightness of these other colored areas shall be1.0 0.50 foot-lambert.3.3.6 Stray light. The lighting system shall be so h
20、oused as to prevent the leakage ofstray light and to shield all lamp filaments from direct view.3.3.7 Light leakage. The lighting system shall in no way restrict the visibility of anygraduations, numerals, pointers, or other specific markings.Provided by IHSNot for ResaleNo reproduction or networkin
21、g permitted without license from IHS-,-,-MIL-L-27160 (USAF)43.3.8 Knobs and lettering. Unless otherwise specified in the applicable instrumentspecification, all indicia associated with instrument knob positions and all lettering on theinstrument face shall be illuminated. The brightness range shall
22、be as specified herein.3.4 Indicia. The presentation may be combination of white, black, and gray as specified inthe applicable instrument specification. Unless otherwise specified in the applicableinstrument specification, the colors shall conform to Table I.Table I. ColorsColor Color No. as listed
23、 inFED-STD-595White 37875Black 37038Gray 364403.5 Contrast. Contrast between the white and black portions of the indicator scale shallbe 12 or greater. Contrast between the gray and black portions of the indicator scale shallbe five or greater. Contrast, C, is defined as:C = B2- B1B1Where: B2is the
24、brightness of the gray or white, and B1is the brightness of the blackportions of the instrument scales.4. QUALITY ASSURANCE PROVISIONS4.1 Responsibility for inspection. Unless otherwise specified in the contract or purchaseorder, the supplier is responsible for the performance of all inspection requ
25、irements asspecified herein. Except as otherwise specified in the contract or order, the supplier mayuse his own or any other facilities suitable for the performance of the inspectionrequirements specified herein, unless disapproved by the Government. The Governmentreserves the right to perform any
26、of the inspections set forth in the specification wheresuch inspections are deemed necessary to assure supplies and services conform toprescribed requirements.4.2 Classification of tests. The inspection and testing of systems shall be classified asfollows:a. Qualification or preproduction tests as s
27、pecified in the applicable instrumentspecification.b. Quality conformance tests.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-L-27160 (USAF)54.3 Test conditions4.3.1 Standard atmospheric conditions. Unless otherwise specified, tests shall becon
28、ducted at an atmospheric pressure of 22 to 32 inches Hg, at a temperature of 2510C, and at a relative humidity of 80 percent or less.4.3.2 Environmental conditions. The tests specified in 4.5, with the exception of 4.5.4and 4.5.7, shall be performed after completion of the environmental tests requir
29、ed by theapplicable instrument specification. Where possible, the brightness and color tests shall beperformed after each environmental test specified in the applicable instrumentspecification. The tests shall be conducted in the sequence specified under 4.5.4.4 Quality conformance tests. Quality co
30、nformance tests shall consist of:a. Individual testsb. Sampling tests.4.4.1 Individual tests. Each lighting system shall be subjected to the following tests asdescribed under 4.5:a. Examination of product.b. Operation.4.4.2 Sampling tests.4.4.2.1 Sampling plan A. One system shall be selected at rand
31、om from each 100 or lessproduced on the contract or order and subjected to the following tests as described under4.5:a. Individual tests.b. Light.4.4.2.2 Sampling plan B. Unless otherwise specified (see 6.2), two systems shall beselected at random from the first ten produced on the contract or order
32、 and subjected tothe following test as described under 4.5:a. Sampling plan A tests.b. Life and reliability.c. Contrast.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-L-27160 (USAF)6d. Lamp circuit.e. Dielectric.4.4.3 Rejection and retest. When
33、one system selected from a production run fails to meetthe specification, no systems still on hand or later produced will be accepted until theextent and cause of failure are determined and appropriately corrected. The contractorshall explain to the Government representative the cause of failure and
34、 the action taken topreclude recurrence. After correction, all tests shall be repeated.4.4.3.1 Individual tests may continue. For operational reasons, individual tests may becontinued pending the investigation of a sampling test failure. But final acceptance ofsystems on hand or later produced shall
35、 not be made until it is determined that all systemsmeet all requirements of the specification.4.4.4 Defects in items already accepted. The investigation of a test failure could indicatethat defects may exist in systems already accepted. If so, the contractor shall fully advisethe procuring activity
36、 of all defects likely to be found and the method of correcting them.4.5. Test methods4.5.1 Examination of product. The lighting system shall be examined to determinecompliance with the requirements that can be checked visually.4.5.1.1 Light leakage. The instrument shall be checked to assure conform
37、ance to 3.3.7.Light or reflections emitted from the edge of a coverglass or from around the dial orbetween openings in counters and warning flags shall not be visible when viewed from anypoint on a 36-inch line. The line shall be determined by the intersection of a plane parallelto and 18 inches fro
38、m the front surface of the instrument coverglass and a horizontal plane12 inches above the geometric center of the instrument coverglass.4.5.2 Operation. the lighting system shall be excited with 5.0V and examined todetermine that all lamps function properly.4.5.3 Lamp circuit. The instrument shall
39、be opened and the lamp circuit checked asfollows. The examination shall be made prior to sealing.a. Determine if lamps are connected in parallel.b. Determine if the lighting circuit is connected as indicated on the wiring diagram.c. Determine if any resistances are used to drop the input voltage to
40、the lamps, or if anytransformers are used to vary the voltage to the lamp terminals.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-L-27160 (USAF)7d. Determine if at least two lamps are used.e. Determine if any portion of the display depends sole
41、ly upon one lamp for itsillumination. Not more than 70 percent of the brightness on any portion of the displayshall be illuminated by one lamp.4.5.4 Life and reliability. The lighting system shall be subjected to a life test with 5.00.05V 400 Hz applied to the lighting terminals. The duration of the
42、 test shall be 1,000hours or for a period equal to the life test time required by the applicable instrumentspecification, whichever is greater. Wherever possible, this test shall be performedconcurrently with the reliability or life test, or both, of the instrument specification. Thepower supplied t
43、o the lighting circuit shall be interrupted every 57 minutes for a period ofthree minutes. Measurement of color and brightness shall be made prior to and after thistest. When this test is run as part of the reliability test, the brightness and color shall bemonitored each 500 hours of testing and fa
44、ilure of the instrument to meet either thebrightness or color requirements shall be counted as a reliability failure of that instrument.Pattern failures (the same type of failure on several instruments) shall require redesign andretesting.4.5.5 Light (calibration and measurement of brightness and co
45、lor of white lightedindicators). Light tests shall be made with 4.50 0.050V applied to the lighting terminals.All measurements shall be in complete darkness and with the axis of the photometerperpendicular to the coverglass.4.5.5.1 Equipment. Equipment required for the light test shall be as follows
46、:a. Photo Research Corporation model UB 1/2 Spectra Brightness Spot Meter, orapproved equivalent.b. Microspectar lens.c. Filter holder between meter and lens.d. External foot-lambert meter (internal impedance must match photometer).e. Regulated power supply, 1 percent accuracy (regulating voltage to
47、 the indicator).f. All voltmeters used shall be accurate to with in 1/2 percent of the specified voltage(AC voltmeters should provide readings that are independent of wave form of the appliedvoltage).g. Lamp and opal glass combination calibrated by the National Bureau of Standards(NBS) for 2,854K (o
48、r applicable specified color temperature). This is the colortemperature of the light emitted by the opal glass.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-L-27160 (USAF)8h. the following constants shall be determined:C1= 1.0984 YRC2= 0.3556 Y
49、RC1and C2are determined by solving the following equations simultaneously:0.4476 = RC1Y+RC1+BC20.4076 = YY+RC1+BC24.5.5.2.1 Color correction graph. Known light sources shall be determined by takingspectral analysis data and computing the true x and y coordinates for a NBS combinationof 2360K light source and filter which yield color coordinate limits as specified herein. Aminimum of the four corners of the s
