1、flIL-HDBK-208Q 3499770 02127b3 43T NOTE: MIL-SllJ-20omnanding Officer, Engineering Specifications and Standards Department (Code 93), Kaval Air Engineering Center, Lakehurst, NJ 05733, II? using the self-addressed Standardization Document Improvement Proposal (DG Form 1416) appearing at the end of t
2、his document or by letter. li Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-2084 = 9999970 0232765 202 Hantainability it3 an attribute of design and ia a measure of the ease, rapidity, and accuracy vith which systems or equipment can be re
3、stored to operational status following failure ar repair. A high degree of readiness and availability of avionic and electronic syetcme and equipment can be assured only when their design allow6 for positive and accurate identification of operational statua, and when items are found defectlve, rapid
4、 end eff iclent fault solation, removal, replacement, and eubaequeut r opair b The rpecal features designed and built into systems which make them emy to auintain and efficient to support result when maintainability Is clearly deflned as a syetan requirement and the nrafntaibility progrsm is establi
5、shed as a functional area of design. The purpose of this atandsrd le not to subrogate the maintainability progrsm requirement8 of MIGSTD-470, but merely to amplify the design criteria requirements of the maintainability program and to emphasize maintainability by design. Under the concept of maintai
6、nability by design, emphasis is placed on those design areas which tend to have the greatest influence on ease of rartfntenance. Thle Includes requirements for moduhrization, replacement at higher levelr, and increased depth of localization, These physical and technical consideratione of maintainsbi
7、litp design are necessary if cmpll,r. cvianlc erd cltstrfl-ic spstm =c! eq-rc sf :b dzctrriic systsr,. The following criteria a. b. C. shall apply : Switches shall not be placed in series psths for purposes of introducing stimuli, introducing normal signals, ar measuring system performance. Isolatio
8、n shall be provided at signal functions with BIT circuitry and devices and other fault isolation circuitry such that normal BIT or other test operations will not affect system performance, nor vil1 failure of BIT interfere with sps tem operation, BIT stimuli shall be selected such that Bystem perfon
9、pance degredation is minimized ln the presence of the stimuli. 11. Indicators. Indicators shall be utilized to provide clear Indications Of electronic system operational readiness and fault locations. lndiatOr8 selected shall comply wtth the requirements of MIL-STD-1472. For integrate or multi-mode
10、systems, indicators for th various subsystems and equipment may be grouped together in an electronic syatem readiness advisory panel. Requirement 104 6 April 1982 106-5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-20BY MIL-STD-2084 (As) 1
11、1.1 Aircrew statlon indicators. Electronic system status and caution or warning indicators shall be designed and applied in accordance with the requirements of MIL-STD-411. The system status indicators shall provide GO/NO GO indications of system readiness or functional status. 11.2 Fault indicators
12、. Fault indicators shall continuously sense fault signals and provide indications at the aircrew station and, as required, at the WRA or SRA level. BIT fault location features shall energize a GO/NO GO device located at the WRA and, to the extent practicable, at the SRA. Fault location indicators at
13、 the WRA level shall be capable of holding the last test result if power is interrupted or removed. All fault location indicators shall be visible to maintenance personnel with the item in its normally installed position. 11.3 Maintenance panel. One of the WRAs provided for an integrated or multi-mo
14、de electronic system my be a maintenance panel. Vnen provided, a maintenance panel shall be placed in a weapon system so it may be readily viewed and operated by maintenance personnel with all WRAs in their normally installed position. A maintenance panel shall, as a minimum, consist of a group of s
15、everal visual fault indicators which will indicate to maintenance personnel which WRA has malfunctioned. Ta reduce the number of indicators required, the maintenance panel may contain a switch(es) and a failure summary indicator(s) which is independent of switch position. 12. Sensors. Passive sensor
16、s shall be used in preference to active sensors wherever possible. Where active sensors are used to provide the necessary information not obtainable from passive sensors, there shall be minimal effect on the reliability of the circuit-sensor combination. 12.1 Calibration. The use of sensors requirin
17、g calibration, initial or othewise, shall be avoided. 12.2 Shielding. All sensors shall be designed so that interference caused by electromagnetic radiation is minimized through the use of good design principles and by filtering or shielding as required. Electromagnetic interference requiremenrs of
18、the electronic system specification shall apply. 13. BIT fault detection and isolation level verification. When reliability development tests in accordance with MXL-STD-Z068(AS) are required by conrract, the contractor shall niaintain a record of all faiiures and develop data to verify the WRA and S
19、RA fault detection and isolation requirements. On the occurrence of an electronic system failure, the 3IT function shall be exercised and a record made in the test log and in the failure report of BIT capability to fault detect and fault isolate in accordance with this requirement. During repair and
20、 ?zquirement 104 5 April 1982 104-6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-Sm-2084 (AS) troubleehmtfng, BIT capability to fault isolate to the faulty SRA shall be recorded. BIT failures or the inability of BIT to detect or isolate failur
21、es shall be reported and Investigated in accordance with the failure reporting, analyeis, and corrective action requirements of MIL- ST”2068(AS). Qe failure suannary report required by contract shall include the listing of al1 reported BIT failures and malfunctions. Data from all primary system fail
22、ures occurring during the reliability development teet ehrll be used to evaluate WRA and SA fault detection and isolation requirements. These data shall be summarized and reported in the reliability teet rerults reports. 14. Details to be specified. Details to be specified in the Statement of Work s
23、hall Include the following, 88 applicable. B. Identification of maintenance and support concepts, b. Ptojected facility, training program, skills, and equipment availability. C. Specificatisn of particular continuous monitoring or operational resting requirements. d. Specification failure and out-of
24、-tolerance mode detection requirements. e. Specification of mximun: BIT self-test time. f. Specification of a reliability development tes: in accordance with MZL-STD-2068 (AS) . g. Identification of test attribute data to be reported (proportion of detection, percent isolation, false alarm rate, amb
25、iguity, etc. ) h. Delivery identification of any data items required. 104-7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1 Purgom. Thlr rrquiremrrnt establishes the criteria for the deeign end appUcation of test points which will adequately euppor
26、t the defined maintenance concept. 2, Referenced doculPLnta. The foll4wing documente ate applicable to Requitunent 10s. STANDARDS Hilitpry Hft Sm4 15 Teet Provisions for Electrical Syeteme and Aesocated Equfpment, Design Criteria for MIGSTD-454 Standard General Requirements for Electronic Equipment
27、MIGSTP2076 Unit Under Test Compatibility with Automatic Test Equipment; General Requirements for 3. Definitions. Definitions sppllcable to Requirement 105 are in 8ccordanct vith HIL-ETb415, ?!A.LI-,S?!2-454, ?CL-,SI?-28?6, Srrti,n 3 of this standard. 4. Tesr pointa. Both external and internal test p
28、oints shall be provided which will permit the functionel and static parameters of an electronic syetem to be monitored, evaluated, and Isolated. The number Of test points shall be kept to a minim but sufficient to provide the ecope of maintenuncc required by the defined maintenance concept. 5. Deei,
29、 Teet points shall be designed 88 an integral part of the electronic system design in accordance with this requirement and MIL- STD-415. Tset points provided shall permit quantitative testing, performsnce monitoring, fault isolation, and calibration or alignment. Test point compatibility with the de
30、signated or pianned Automatic Test Equipment (ATE) ehall be in accordance kdth MIL-STD-2076. 5. I External test points. External test points shall be grouped, to the extent practicable, ln 8 single multl-pin connector which ie readily accessible on the surface of each WRA to permit testing while the
31、 WRA is in its normally instslled position in the weapon syetem and without need for disconnecting operational connectors. Unless othewiee epeclfied, external test points shall be provided for the functional checkout and monitoring of the electronic eystem and for WRA and SU f alt: isolation, To the
32、 extent practicable, the functional and fault isolation teet points shall be combined in a single connector. All external test point connectore shall be provided with captive caps. 105-1 Requirement 105 6 Apri 1 1982 Provided by IHSNot for ResaleNo reproduction or networking permitted without licens
33、e from IHS-,-,- MIL-HDBK-2084 9999970 02L278b T37 5.2 Organizational level test points. The external test points shall permit application of external functional etimuli for conductlng en-to-end quantitative checkouts and measurements of the electronic system functional performance. The fault isolati
34、on test points shall permit unmnbiguoua fault isolation, calibration or all-t of W, and checkout or calibration of BIT while the WRAs are installed in their normal position ln the weapon system. 5.3 Shop repair test points. External test pointe shall be provided on each WRA for use when the WRA is r
35、emoved from the Ve8pOn system. The external test points, ln conjunction with the operational * connectors, shall permit end-to-end quantitative checks, calibration or alignment, and other functional testing of the WRA. External test pointa shall also pennit, fn the went of a failure, the fault isola
36、tion of the faulty SU or circuit within the W. The acceptable percsntagc of all URA faults which ehall be isolated to the faulty SU, or small group of SRAs, by ATE utilizing external test points shall be 88 listed ln Table 105-1. Table 105-1. Nonambiguous SRA iso18tion RTOUPB. *WU. 1 nn* 90% * 1 SRA
37、 5.4 Xnternal test paints. Internal test points shall be provided on each SRA to pennit the application of external stimuli aud to permit external measurement of performance when the SRA is removed from the WRA. Internal test points shall be conditioned to provide undistorted signals to the teet equ
38、ipment and shall provlde the meam for measuring input and output parameters to enable calibration or alignment of SRAS. The Internal test points shall also petmit, in the event of failure, the isolation of the faulty subassembly, sub-=, or part within the SRA. The acceptable percentage of all SRA fa
39、ults which shall be solated to the faulty subassembly, eub-SU, or part, or ad1 group of subaesemblles, eub-SRAs, or parts, ehall be 88 listed in Table 105-11. 6. Manual fault isolation level. Provisions and procedures shall be developed which enable the ambiguous SM groups resulting from BIT or ATE
40、Isolation to be further isolated to the faulty SRA. No special support equipment shall be required and isolation procedures shall not include the use of spare SUS from the supply system. Requirement 105 6 April 1982 105-2 Provided by IHSNot for ResaleNo reproduction or networking permitted without l
41、icense from IHS-,-,-MIL-STD-2084 (AS) Table 105-11. Fault isolation groups within SRA. I ._ SUBASSEKBLY OR PART GROUP SIZE XE SRA OF I SM FAULTS GROUP SIZE GROUP SIZE XSOLATED 10 - c 10 r 7. Automatic test equipment (ATE) compatibility. The electronic system and each WRh and SU shall be designed to
42、be compatible with the ATE designated or planned for fleet use. Compatibility requirements snall be in accordance with MIL-STD-2076(AS). 8. Details to be speclf led. Details to be specified in the Statement of Work shall include the following, as applicable: (R) a. Operational and support concepts a
43、n requirements, including eE-v*irrzsritd cudi Lions. b. Lisrs of standard tools, equipment , and designated or planned Automatic Test Equipment. c. Projected facility, training program, skills, and equipment d. manual e. reported ambiguity f. required. availability . Establishment of PA approval req
44、uirements for fault isolation provisions and procedures. Identification of test attribute data to be (proportion of detection, percent isolation, rates, etc. ). Delivery identification of any data items Requirement 105 6 April 1982 105-3 Provided by IHSNot for ResaleNo reproduction or networking per
45、mitted without license from IHS-,-,-MIL-HDBK-20B4 9999770 02329% AClT R REpnIREHENT 106 MAINTAINABILITY INDEX 1. Purpose. This requirement establishes criteria for determining maintainability indices of the electronic system. 2. Referenced documents. The following referenced document is applicable t
46、o Requirement 106. STANDARDS Military MIL- ST. The SR4 FI ratio is calculated as follows: Huaber of SRAS not requirinr, adiustment F ,= Total Number of SR+ in the WRA . Reqrlirement 106 6 Apri 1 1982 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MT
47、L-STD-2084 (AS) 5. tight replaceable assembly (LM) ratio. Unless othervlse specified, Che ratio of LW to the total number of WRAs in the electronic system shall not be less than 1.0. Analytical estimates of the LRA ratio shall be a consideration at all design reviews, The LRA ratio is calculated as
48、f ul:ows : LRA ratio = Number of LU in electronic system Total number of WRAS in electronic system 6. Quick replaceable assembly (QRA) ratio. The ratio of QRAS to the tljtai nuinber df SRAs in a WRA shall not be less than 0.90. Analytical estimates of the QRA ratio for each WRA shall be a considerat
49、ion at all desiRn i-eviews. The QRA ratio is calculated as follows: “ Number of QRAs in WRA QRA ratio Total number of SRAS in WRA 7. FI ratio verification. When WRAS and SRAs are replaced OT substituted durin however, individual maintainability program tasks from MIL-STD-470 may be cited in the contract wichout requiring Requirement 101. 50. DETAIL REQUIREXENTS 50.1 Requirement 101 - Maintainability P
