MIL-STD-1629-RevA - Barringer and Associates, Inc.

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MTl,-STl)-lii?(l ATASK 101FAILURE MODE AND EFFECTS ANALYSIS1. Purpose. The purpose of the FMEA is to study the resultsor effects of item failure on system operation and,to classify eachpotential failure ~ccording to its severity.2. Documents referenced in Task 101:SPECIFI CATIONSMilitarvSTANDARDSHIL-M-24100 Manual, Technical, Functionally Oriented MaintenanceManuals (FOMM) for Equipment and SystemsMilitaryMIL-STD-756 Reliability PredictionMIL-STD-78Cl lkfinitions of item Levels, item Exchangeability,Models and Related Terms:3. Analysis approach. Variations in design complexity andavailable data will generally dictate the analysis approach to be used.There are two primary approaches for accomplishing an FMEA. One is thehardware approach which lists individual hardware items and analyzestheir possible failure modes. The other is the functional approachwhich recognizes that every item is designed to perform a number offunctions that can be classified as outputs. The outputs are listed andtheir failure modes analyzed. For complex systems, a combination of thefunctional and hardware approaches may be considered. Tile FMEA may beperformed as a hardware analysis, a functional analysis, or a combinationanalysis and may be initiated at either the highest indenture level andproceed through decreasing indenture levels (top-down approach) or atthe part or assembly level and proceed t}]rougllincreasing indenturelevels (bottom-up approach) until the FMEA for the system is complete.3.1 Hardware approach. The hardware approach is normallyused when hardware items can be uniquely identified from schematics,drawings, and other engineering and design data. The hardware approachis normally u~ilized in a part level up fashion (boLtom-up approacl~);however, it can be initiated at i~ny lC!VC1 of indenture and progress ineither direction. Eat}) identified f,~ilurt-mode shall be assigned aseverity classification wl]ich will be utilizud during design LO establishpriori~ies for corrective actions. *‘-)1*,,
MT1,-STD-1629A3.2 Functional approach. The functional approach is normallyused when hardware items cannot be uniquely identified or when systemcomplexity requires analysis from the initial indenture level downwardthrough succeeding indenture levels. The functional approach is normallyutilized in an initial indenture level down fashion (top+own approach);however, it can be initiated at any level of indenture and progress ineither direction. Each identified failure mode shall be assigned aseverity classification which will be utilized during design to establishpriorities for corrective actions.3.3 Failure mode severity classification. Severity classificationsare assigned to each failure mode and each item to provide a basis forestablishing corrective action priorities. First priority shall begiven to the elimination of the identified Category I (catastrophic) andCategory 11 (critical) (see General Requirements, 4.4.3) failure modes.Where the loss of input or output at a lower indenture level is criticalto the operational success of a higher indenture level, action shall betaken to eliminate or control the identified failure modes. When identifiedCategory I and Category II failure modes cannot be eliminated or controlledto levels acceptable to the procuring activity, alternative controls andrecommen~at~ons shall be presented to the procuring activity.4. Procedure. Each single item failure, as its effects areanalyzed, is to be considered the only failure in the system. Where asingle item failure is non-detectable, the analysis shall be extended todetermine the effects of a second failure, which in combination with thefirst undetectable failure, could result in a catastrophic or criticalfailure condition. Passive and multiple failures which may result incatastrophic or critical conditions shall also be identified. Whensafety, redundant, or back-up items exist, failure assumptions shall bebroadened to include the failure conditions which resulted in the needfor the safety, redundant, or back-up item. Design changes or specialcontrol measures shall be identified and defined for all catastrophic(Category I) and critical (Category 11) failure modes. All singlefailure points identified during the analyses shall be uniquely identifiedon the FMEA worksheets to maintain visibility of these failure modes.4.1 System definition. The first step in performing the FMEAis to define the system to be analyzed. Functional narratives shall bedeveloped for each mission, mission phase, and operational mode andinclude statements of primary and secondary mission objectives. Thenarratives shall include system and part descriptions for each missionphase and operational mode, expected mission times and equipment utilization,functions and uu~put of each item, and conditions which constitutesystem and part failure,4.1.1 Mission functions and operational modes. The systemdefinition shall include descriptions of each mission in terms of functionswhich identify the task to be performed and the functional mode ofTASK 10124 November 1980101-2
Page 1 and 2: MIL-STD-1629A24 NOVEMBER 1980SUPERS
Page 3 and 4: MT7,-STW 1629AFOREWORDIThe~failure
Page 5 and 6: ----MIL-STD-16Z9ACONTENTS(Continued
Page 7 and 8: MI1.-STD-1629A1. SCOPEThis standard
Page 9 and 10: MTL-STD-1 629A3. DEFINITIONS3.1 Ter
Page 11 and 12: !’11 L-!;’J’l)- 1629A3. 1.17.
Page 13 and 14: .MT1.-ST~-l629A4.3.5 Failure defini
Page 15 and 16: MTT,-sTn-1629Afor each mission, mis
Page 17: ?f?l.-STD-l629Ab. Des~ripGlon of de
Page 21 and 22: MI J,-STD-16?9Afunctional block dia
Page 23 and 24: MI L-STD-1629A5.6.2 Next higher lev
Page 25 and 26: Ml 1,-STD-1079Afurther amplified in
Page 27 and 28: MIL-STD-1629A. --1III[IIIIIIIIIIIii
Page 29 and 30: MIL-STD- 1629ATASK 102CRITICALITYAN
Page 31 and 32: IMII.-ST1)-162(]Ashown in Figure 10
Page 33 and 34: MIL-STD-1629Awhere:C* = Criticality
Page 35 and 36: MI I.-sTI)-I629AINCREASINGCRITICALI
Page 37 and 38: MIL-STD-1629A3*1 Failure predictabi
Page 39 and 40: .--— .-—--— , --—— ——
Page 41 and 42: MTL-STD- 1629A4\l Damage modes. All
Page 43 and 44: NI 1.-[; 1’1)- 1(); ?!)Au0.-.mr-r
Page 45 and 46: MI I,-ST1)-1629A3. Content. The FME
Page 47 and 48: —..-A 1MIL-STD-1629AAPPENDIXA10.
Page 49 and 50: MIL-STD-1629A50.1.3 Intended use. T
Page 51 and 52: MIL-STD-1629AWhere:C= “ Criticali
Page 53 and 54: INSIRUCII ONS: In ● continuing ef
Page 55 and 56: MIL3TD-1629ANotice 17 June 1983MILI
Page 57 and 58: MIL-STD-1629ACONTENTS (Continued)Fi
Page 59 and 60: MIL-STD-1629ASPECIFICATIONSMilitary
Page 61 and 62: MIL-STD-1629Ad. Functional Failure
Page 63 and 64: MIL-STD-1629A..2’Ilm.o.,id1-< xQ
Page 65 and 66: —MIL-STD-1629A50.5 DMEA (Task 104
Page 67 and 68: MIL-STD-1629ACONTENTS (Continued)Pa
Page 69 and 70:
.-MIL-STD-1629AAPPENDIX AAPPLICATIO
Page 71 and 72:
20-30Stop LCNMIL-STD-1629AEnter the
Page 73:
NOTICE OFCANCELLATIONNOT MEASUREMEN
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