1、IiifTERNATlONALAEROSPACElM Engineering Societyr Advancing MobilityLand Sea At and Space,ommonweatth Drive, Wavrendale, PA 150954001INFORMATIONREPORTSubmitted for recognifion as an American National Standard= AIR4896Issued 1995-l 2RECOMMENDED RMS TERMS AND PARAMETERS1.2.2.12.23.3.13.23.2.13.2.23.2.33
2、.2.4,3.34.4.14.2FIGURE 1APPENDIX AAPPENDIX BTABLE OF CONTENTSSCOPE.2REFERENCES .2Military Publications 2Other Documents .4APPROACH .4Discussion of Data Base Generation 4Selection/Recommendation Process 5Selection of Terms Applicable to RMS .5Identification of Parametric Terms5Selection of Recommende
3、d Terms 5Selection of Preferred Definitions .6Subcommittee Consensus Process 6HOW TO READ THIS REPORT. 6Sample Report Page 6Contents of Published Report.7Headings and Associated Definitions of Each Field7LIST OF RECOMMENDED TERMS.0COMPLETE UST OF RMS TERMS REVIEWED. 24WE Technicel !3tandards Board R
4、ules provide that: Ibis report is published by SAE to advance the stale of technical and engineering sciences.Theuse oi this rqwt is enMy vduntary. and its appkaMy and suitebilii for any particular web inctuding any patent infringement arising therefrom. is thewle nx3ponsibility of the user:SAE mvie
5、w each technical report at least every live years at which tima it may be p 2 1 ali return from an assigned mission with one ormore previously work g ( 3: -t 31 systems/subsystems inoperable (includingground and air abork .BREAK RATE = # Ml 31 :I4 4 ITH 1 OR MORE FAILURES OFESSENTlAL ITEMS # f E $1
6、; !( INS ASSIGNEDYesBUILT IN TESTAn integral capability 11 jt f: E. II )ment which provides an on-board,automated test capak Iity : : !t- c:t, diagnose, and/or isolate system failures.The fault detection ar 1, p :x. 11” , isolation capability is used for periodic orcontinuous monitorin: ,3f t i xrns
7、 operational health, and for observationand, possibly, diagno is E E, 2: JI lblde to maintenance action.NoSAE AIR4896Term:Definition:Parameter?:Document Number:Document Name:Term:Definition:Parameter?:Document Number:Document Name:Term:Definition:Formula:Parameter?:Document Number:Document Name:CANN
8、OT DUPLICATEA fault indicated by BIT or other monitoring circuitry which cannot beconfirmed at the next level of maintenance.NoMIL-STD-1309CDEFINITIONS OF TERMS FOR TEST MEASUREMENT AND DIAGNOSTICEQUIPMENTDIRECT MAINTENANCE MAN-HOURSThe total time in direct man-hours required to restore or maintain
9、an item inserviceable condition.NoMIL-E-005007EENGINES, AIRCRAFT, TURBOJET AND TURBOFAN, GENERALSPECIFICATION FORDIRECT MAINTENANCE MAN-HOURS PER MAINTENANCE ACTION(DMMH/MA)A measure of the maintainability parameter related to item demand formaintenance manpower. The sum of direct maintenance man-ho
10、urs dividedby the total number of maintenance actions (preventative and corrective)during a stated period of time.DMMH/MA = TOTAL DMMH / TOTAL MASYesMIL-STD-721 CDEFINITIONS OF TERMS FOR RELIABILITY AND MAINTAINABILITY-9-SAE AIR4896Term:Definition:Parameter?:Document Number:Document Name:Term: DOWNT
11、lMEDefinition: The time during which an item is not available for use for technical reasons.Term:Definition:Formula:Parameter?:Document Number:Document Name:Term:Definition:Formula:Parameter?:DOWNING EVENTThe event which causes an item to become unavailable to initiate its mission.NoMIL-STD-721 C,DE
12、FINITIONS OF TERMS FOR RELIABILITY AND MAINTAINABILITYDOWNTIME, MEANThe average elapsed time between loss of mission capable status andrestoration of the system to mission capable status.MDT = TOTAL DOWNTIME / # OF DOWNING EVENTSYesAFP 57-9DEFINING LOGISTICS REQUIREMENTS IN STATEMENT OFOPERATIONAL N
13、EEDEFFECTIVENESS, BUILT IN TESTThe product of two independent probabilities:a. Pd(BIT) = The probability that a failure will be detected byBIT.b. Pi(BIT) = The probability that the failure will be isolatedto a stated ambiguity level by BIT.EFFECTIVENESS, BIT = Pd(BIT) * Pi(BIT)Yes-lO-SAE AIR4896Term
14、:Definition:Parameter?:Document Number:Document Name:Term:Definition:Formula:Parameter?:Document Number:Document Name:Term:Definition:Parameter?:Document Number:Document Name:FAILUREThe inability of an item to perform within previously specified limits.NoMIL-HDBK-338ELECTRONIC RELIABILITY DESIGN HAN
15、DBOOKFAILURE RATEThe total number of failures within an item population divided by the totalnumber of life units expended by that population during a particularmeasurement interval under stated conditions.FAILURE RATE = # FAILURES / LIFE UNITSYesMIL-STD-721 CDEFINITION OF TERMS FOR RELIABILITY AND M
16、AINTAINABILITYFAULTA physical condition that causes a device, component, or element to fail toperform in a required manner; for example, a short circuit or a broken wire.NoMIL-STD-1309CDEFINITIONS OF TERMS FOR TEST MEASUREMENT AND DIAGNOSTICEQUIPMENT-ll-SAE AIR4896Term:Definition:Parameter?:Document
17、 Number:Document Name:Term:Definition:Formula:Parameter?:Term:Definition:Parameter?:Document Number:Document Name:FAULT ISOLATIONThe process of determining the location of a fault to the extent necessary toeffect repair.NoMIL-STD-721 CDEFINITIONS OF TERMS FOR RELIABILITY AND MAINTAINABILITYFIX RATET
18、he percent of items that return Not Mission Capable that are repaired (i.e.,returned to Mission Capable status) in a specified number of clock hours, i.e.,70% in 4 h, 85% in 8 h.FIX RATE = # A/C REPAIRED WITHIN SPECIFIED HOURS / # ITEMSREPAIREDYesLIFE CYCLE COSTThe total cost of research, developmen
19、t, test, and evaluation; acquisition;operation and support and disposal of an item throughout its useful life.YesNAVAIR 01-l A-32RELIABILITY ENGINEERING HANDBOOK- 12-r- SAE AIR4896Term:Definition:Parameter?:Document Number:Document Name:Term:Definition:Parameter?:Document Number:Document Name:Term:D
20、efinition:Parameter?:Document Number:Document Name:LIFE UNITSA measure of use duration applicable to the item (such as operating hours,cycles, distance, rounds fired, attempts to operate).NoDOD 5000.40(D)RELIABILITY & MAINTAINABILITY (P&L)MAINTENANCEAll actions (corrective and preventive) necessary
21、for retaining an item in orrestoring it to a specified condition.NONAVAIR 01-l A-32RELIABILITY ENGINEERING HANDBOOKIMAINTENANCE ACTIONAn element of a maintenance event. One or more tasks (i.e., faultlocalization, fault isolation, servicing and inspection) necessary to retain anItem in or restore it
22、to a specified condition.NoMIL-STD-721 CDEFINITIONS OF TERMS FOR RELIABILITY AND MAINTAINABILITYI-13-SAE AIR4896Term:Definition:Parameter?:Document Number:Document Name:Term:Definition:Formula:Parameter?:Term:Definition:Parameter?:Document Number:Document Name:MAINTENANCE EVENTOne or more maintenanc
23、e actions required to effect corrective andpreventive maintenance due to any type of failure or malfunction, false alarmor scheduled maintenance plan.NoMIL-STD-721 CDEFINITIONS OF TERMS FOR RELIABILITY AND MAINTAINABILITYMAINTENANCE MAN-HOURS PER LIFE UNITA measure of the total maintenance manpower
24、burden required to maintainan item. It is expressed as the cumulative number of man-hours ofmaintenance expended in direct labor during a given period of the life unitsdivided by the cumulative number of end item life units during the sameperiod.MMlULU = TOTAL MAINTENANCE MAN-HOURS / TOTAL LIFE UNIT
25、SYesMAINTENANCE TIME, ELAPSED (EMT)For the purposes of maintenance data reporting (MDR), EMT is defined asthe actual clock time, in hours and tenths, that maintenance was beingperformed on a job. EMT does not include the clock hours and tenths forcure time, charging time, or leak test when they are
26、being conducted withoutmaintenance personnel actually monitoring the work. Although the EMT isdirectly related to job man-hours, it is not to be confused with total man-hoursrequired to complete a job. For example, if five persons complete a job in 2h of continuous work, the EMT = 2 h and the man-ho
27、urs = 10.NoOPNAVINST 4790.2THE NAVAL AVIATION MAINTENANCE PROGRAM-14-SAE AIR4896Term:Definition:Parameter?:Document Number:Document Name:Term:Definition:.-1Parameter?:Document Number:Document Name:.- IMAINTENANCE, CORRECTWEAll actions performed as a result of failure, to restore an item to a specifi
28、edcondition. Corrective maintenance can include any or all of the followingsteps: localization, isolation, disassembly, interchange, reassembly,alignment, and checkout.NoMIL-STD-721 CDEFINITIONS OF TERMS FOR RELIABILITY AND MAINTAINABILITYMAINTENANCE, PREVENTIVETests, measurements, replacements, adj
29、ustments, repairs, and similaractivities carried out with the intention of preventing faults or malfunctionsfrom occurring during subsequent operation. Preventive maintenance isdesigned to keep hardware and software in proper operating condition andmay be performed on a scheduled basis.NoMIL-STD-130
30、9CDEFINITIONS OF TERMS FOR TEST MEASUREMENT AND DIAGNOSTICEQUIPMENT-15-SAE AIR4896Term:Definition:Formula:Parameter?:MEAN CORRECTIVE MAINTENANCE TIMEThe mean elapsed time required to complete a corrective maintenanceaction, i.e., total corrective maintenance down time divided by total correctivemain
31、tenance actions over a stated period of time.MCT = TOTAL CORRECTIVE MAINTENANCE DOWN TIME / TOTALCORRECTIVE MAINTENANCE ACTIONSYesTerm:Definition:Parameter?:Document Number:Document Name:MAN-HOURSThe total number of accumulated direct labor hours (in hours and tenths)expended in performing a mainten
32、ance action. Direct maintenance man-hours are man-hours expended by assigned personnel to complete the workdescribed on the source document. This includes the functions ofpreparation, inspection, disassembly, adjustment, fault correction,replacement or reassembly of parts, and calibration/tests requ
33、ired inrestoring the item to a serviceable status. It also includes such associatedtasks as checking out and returning tools, looking up part numbers in theIllustrated Parts Breakdown (IPB), transmitting required information tomaterial control, and completing documentation of the Visual InformationD
34、isplay System/Maintenance Action Form (VIDSIMAF) or Support ActionForm (SAF).NoOPNAVINST 4790.2THE NAVAL AVIATION MAINTENANCE PROGRAMTerm:Definition:Parameter?:Document NumberDocument Name:MAN-HOURS, MAINTENANCEThe man-hours required to complete the maintenance task.NoWATOGWORLD AIRLINES TECHNICAL O
35、PERATIONS GLOSSARY-16-SAE AIR4896Term:Definition:Formula:Parameter?:Document Number:Document Name:Term:Definition:Formula:Parameter?:Document Number:Document Name:Term:Definition:Formula:Parameter?:MEAN MAINTENANCE TIME (MMT)The measure of item maintainability taking into account maintenance policy.
36、The sum of elapsed corrective and preventive maintenance times divided bythe sum of preventive and corrective maintenance events during a statedperiod of time.MMT = SUM OF ELAPSED PREV AND CORR MAINT TIME / SUM OFPREV AND CORR MAINT EVENTSYesMIL-STD-721 CDEFINITIONS OF TERMS FOR RELIABILITY AND MAIN
37、TAINABILITYMEAN TIME BETWEEN DEMANDS (MTBD)The total number of system life units divided by the total number of demandson the supply system during a stated period of time.MTBD = TOTAL SYSTEM LIFE UNITS / TOTAL # OF ITEM DEMANDSYesMIL-STD-721 CDEFINITIONS OF TERMS FOR RELIABILITY AND MAINTAINABILITYM
38、EAN TIME BETWEEN FAILURES (MTBF)A reliability figure calculated by dividing total life units accrued in a period bythe number of failures that occurred during the period.MTBF = TOTAL LIFE UNITS IN PERIOD / NUMBER OF FAILURES INPERIODYes-17-SAE AIR4896Term:Definition:Formula:Parameter?:Document Numbe
39、r:Document Name:Term:Definition:Formula:Parameter?:Document Number:Document Name:MEAN TIME BETWEEN MAINTENANCE (MTBM)A measure of reliability taking into account maintenance policy. The totalnumber of life units expended by a given time divided by the total number ofmaintenance events (scheduled and
40、 unscheduled) due to that item.MTBM = TOTAL LIFE UNITS / TOTAL MAINTENANCE EVENTSYesMIL-STD-721 CDEFINITIONS OF TERMS FOR RELIABILITY AND MAINTAINABILITYMEAN TIME BETWEEN REMOVALS (MTBR)A measure of the system reliability parameter related to demand for logisticsupport. The total number of system li
41、fe units divided by the total number ofitems removed from that system during a stated period of time. This term isdefined to exclude removals performed to facilitate other maintenance andremovals for product improvement.MTBR = TOTAL LIFE UNITS / TOTAL NUMBER OF REMOVALSYesMIL-STD-721 CDEFINITIONS OF
42、 TERMS FOR RELIABILITY AND MAINTAINABILITY-18-Formula:Parameter?:Documlent Number:Docum(ent Name:-.ITerm:Definition:Formula:Parameter?:Document Number:Document Name:Term:Definition:SAE AIR4898MEAN TIME TO RESTORE SYSTEM (IvllTRS)A measure of the system maintainability parameter related to availabili
43、ty andreadiness. The total corrective maintenance time associated with downingevents, divided by the total number of downing events during a stated periodof time. (Excludes time for off-system maintenance and repair of detachedcomponents.)Ml-TRS = TOTAL CORRECTIVE MAINTENANCE TIME (DOWNINGEVENTS) /
44、TOTAL NUMBER OF DOWNING EVENTSYesMIL-STD-721 CDEFINITIONS OF TERMS FOR RELIABILITY AND MAINTAINABILITYMEAN TIME TO SERVICE (MlTS)A measure of an on-system maintainability characteristic related to servicingthat is calculated by dividing the total scheduled crew/operator/driverservicing time by the n
45、umber of times the item was serviced.Ml-K = TOTAL SERVICING TIME / NUMBER OF TIMES SERVICEDYesMIL-STD-721 CDEFINITIONS OF TERMS FOR RELIABILITY AND MAINTAINABILITY-19-SAE AIR4896Term:Definition:Parameter?:Document Number:Document Name:Term:Formula:Parameter?:Document Number:Document Name:Term:Formu
46、la:Parameter?:MISSION CAPABLE RATEThe percent of possessed time that a system is capable of performing atleast one of its assigned missions.YesAFP 57-9DEFINING LOGISTICS REQUIREMENTS IN STATEMENT OFOPERATIONAL NEEDPERCENT BIT CANNOT DUPLICATE%CND = 100 x NUMBER OF BIT CNDS / TOTAL NUMBER OF BITINDIC
47、ATIONS”* Excludes false alarms that do not generate maintenance actions.A BIT CND is an on-equipment BIT indication of a malfunction that cannot beconfirmed by subsequent troubleshooting by maintenance personnel.YesAFP 57-9DEFINING LOGISTICS REQUIREMENTS IN STATEMENT OFOPERATIONAL NEEDSPERCENT BUILT
48、 IN TEST FALSE ALARM%FA = 100 x NUMBER OF BIT INDICATIONS NOT RESULTING INMAINTENANCE ACTIONS / TOTAL NUMBER OF BIT INDICATIONSA BIT FA is an indication of a failure that is not accompanied by systemdegradation or failure.Yes-2o-SAE AIR4896Term:Definitilon:Formula:Parameter?:Document Number:Document
49、 Name:Term:Definition:Formula:Paramleter?:Document Number:Document Name:Term:Definition:PERCENT BUILT IN TEST FAULT DETECTIONThe total number of faults detected by BIT divided by the total number offaults x 100.FD = TOTAL FAULTS DETECTED BY BIT / TOTAL FAULTS x 100YesAFP 57-9DEFINING LOGISTICS REQUIREMENTS IN STATEMENT OFOPERATIONAL NEEDSPERCENT BUILT IN TEST FAULT ISOLATIONIn defining this term it is essential to recognize that it is just as operationallyvaluable for BIT to fault isolate on an aircrew reported fault or manuallydetected fault as it is for BIT to fault isolate BIT de
