I n the na nam me of GO GOD Maintenance Management
Part 1
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M ai ainte ntenance nance M ana anag gement
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Maintenance management
By m.shahbazi
4/5/2012
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References 1. Aviation Ma M ainte ntena nanc nce e M an anag age ement Harry Harry A. A. K innison, on, Ph Ph.D. McGra cGraw-Hill w-Hil l --- -- I SBN 0-07-142251-X --- 2004
2. Prod Produ uct ctiivi vity ty and Rel Reliability-B ty-Ba ased Maint nte enance Managem gement. Matthe Matthew P. Stephens Purdue Universi Uni versity ty Press Press West West L afayette, Indiana Indiana
3. Reli Relia ability-C ty-Ce ent nte ere red d Mainte ten nance By: J ohn ohn Moub Moubray ray -Ap -A pril 199 99-- I SBN: SBN : 083 0831130784
4. I ntro trod duct ctiion to Re Relliability Eng Engiineeri rin ng - by E. E. L ewis I SB SBN N: 0-471-01833 -01833-3 -3 -----19 1996
5. Re Relliability En Engineering and Ris Risk An Analys lysiis: A Practical Guide, Second Edition (Quality and Reliability) by M. Modarres (Sep 22, 2009)
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I ntrod ntroduc ucti tio on maintenance 1. Ent Entrop ropy 2. Failure Rate Rate Patte Patterns 3. Othe Otherr M aintenan aintenance ce Consi onsider der ations
quipment redundancy redundancy,, 1. Equipm 2. L ine repl replacea ceable ble units, units, and and
nimum airc aircraf raftt dispa dispatch requi requirements. ents. 3. minim Example: Most commercial jets have two hi high-freq gh-frequency (HF (HF) radios( radios( Only Only oneis needed)
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Maintenance management
By m.shahbazi
4/5/2012
2
Why maintena maintenance nce There is one concept in thermodynamics ics that is ofte ften a The puzzler to students. That concept is labeled entropy "unavailable energy or energy that is unavailable for use. if you want to understand the concept of entropy in practi practica call term terms, s, think think of it as the the di difference rence be between the theoretically perfect system you have on the drawing board board and the actual, physical physical systemyou have in in hand hand The diffe ifference between that which ich we design ign and that The which we can build constitutes the natural entropy of the system.
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Why maintena maintenance nce point nt to understand is that that entr entropy opy not only only One important poi exists exists iin n every every system system, but that that the entropy entropy of a system systemis always increasing. components or systems wil will deteri deteriorate orate from from use use Some compone and some will deteriorate from lack of use (time or envi environm ronmen entt rel relate ated) To summarize ize, then, it is the engine ineer's responsibilit ibility y to To design the system with as high a degree of perfection (low entropy) as possible within reasonable limits. The mechanic' ic's responsibilit ibility y, on the other hand, is to The comba combatt the continua continuall increase ncrease in entropy entropy during duri ng the the operational lifetime of the equipment. 6
Maintenance management
By m.shahbazi
4/5/2012
3
Why maintena maintenance nce The lev level The
of perfec fection ion we have been talkin lking g about can also also be referred referred to as the the reliability of the system. The design igned-in lev level of perfec fection ion is known as the The inherent reliability of that that system. No amount of maintena aintenance can be perf perfor orm med to incr increa ease the system system reliability any higher than this inherent level. However, it is desirable for the operator to maintain this level of reliability (or this level of perfection) at all times.
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Why maintena maintenance nce scheduled maintenance And An d unscheduled maintenance
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Maintenance management
By m.shahbazi
4/5/2012
4
Why maintena maintenance nce This This is a representation ion of the natural increase in entropy of the system or the natural deteriorationo deterioration of the system-over tim ti me. we reduce the entropy to its i ts origina original level vel. This This is is ca called preventive maintenance and is usually performed at regul regula ar intervals. rvals. ( referred to as scheduled maintenance.) 9
Why maintena maintenance nce Effects of redesign on system reliability. During uring thi this rede redesign sign,, new components, new materials, or new technique techniques s may have been used to reduce reduce the natural entropy of the system.
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Maintenance management
By m.shahbazi
4/5/2012
5
Why maintena maintenance nce
Perfection vs. cost. 11
Com omm mon maint mainte enance conce concept pt L RU nother common concept concept used in in aviati viation on is is theline theline A nother replaceable unit (LRU). ponent or system system that that has bee been desi designe gned in in An L RU is a component such a manner that that the par parts that most commonly only fai faill can be quickly removed and replaced on the vehicle. This allows the vehicle to be returned to scheduled service without undue delay for maintenance. The failed part, then, can either be discarded or repaired in the shop as necessary without further delaying the flight.
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Maintenance management
By m.shahbazi
4/5/2012
6
Com omm mon maint mainte enance conce concept pt M EL nimumequi equipm pment li list (MEL). This list allows a vehicle the minim to be dispatched into service with certain items inoperative provided that the loss of function does not affect the safety and operation of the flight. These ite items are ca carefully fully determine ined by the Design igner and The sanctioned by the regulatory authority during the early stages of vehicle design and test. The Design igner iss issues a master minim nimumequi equipment li list The (MM (M MEL ) which which include includes s all equi quipment and access ccessori orie es available for the aircraft model. 13
Com omm mon maint mainte enance conce concept pt M EL The airlin irline e then tailor ilors the document to its its own configu figuration ion The to produ produce ce theMEL Many of these MEL item tems are are associ associate ated with with redunda redundant system systems. The The concept concept of the MEL allows deferral of maintenance without upsetting the mission requi equirem rements. ents. The The maintena aintenance, nce, however, however, must must be perf perfor orm med within certain prescribed periods, ategory ory A before next flight or remarks C ateg 3 days Category B 10 days Category C tegor y D 120 days C ateg 14
Maintenance management
By m.shahbazi
4/5/2012
7
Com omm mon maint mainte enance conce concept pt M EL ssociat ociate ed wi with the the MEL is adispatch a dispatch deviation guide A ss (DDG) that contains instructions for the line maintenance crew when the de deviati viation on req requi uires res some maintena ntenance nce acti action on that that is is not necessa cessari rilly obvious obvious to the mechan echaniic.
A dispatch deviation guide is published by the airplane manufacturer to instruct instruct the mecha echanic nic on these these devi deviati ations.. ons..
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Question: 1. the the mecha chanic res respons onsibility is is : educe natural entro entropy py 1. Reduce ncrease inhe nherent rent rel reliabili bil ity 2. I ncrea ntained inh inhe erent rent rel reliabili bil ity 3. M ainta 4. A ll of the above 2. the the mecha chanic res respons onsibility is is : ncrease natural natural entropy entropy of system system 1. I ncrease 2. Prevent from decreasing the total entropy of the system combatt the continua continuall increase ncrease in entropy entropy during duri ng the 3. to comba operational lifetime of the equipment. 16
Maintenance management
By m.shahbazi
4/5/2012
8
Question: 1. the the mecha chanic res respons onsibility is is : educe natural entro entropy py 1. Reduce ncrease inhe nherent rent rel reliabili bil ity 2. I ncrea nta ained inh inhe ere rent nt rel reliabil biliity 3. M aint 4. A ll of the above 2. the the mecha chanic res respons onsibility is is : ncrease natural natural entropy entropy of system system 1. I ncrease 2. Prevent from decreasing the total entropy of the system combatt the conti continua nuall increa ncrease se in entropy entropy during duri ng the 3. to comba operational lifetime of the equipment. equipment. 17
Question: 3. The conce concep pt of the ……. al allows deferral rral of mainte ntenance nce without upsetting the mission requirements. 1. LRU 2. Reliability 3. MEL aintena nance nce program 4. M ainte 4. MMEL MM EL iss issue by rl ine and approved pproved by authority uthority 1. A irli anufacture acturerr and and approved approved by state of manuf anufacture acturerr 2. M anuf designer gner and approved pproved by state of desi design 3. desi rl ine and approved pproved by state state of desi design 4. A irli 18
Maintenance management
By m.shahbazi
4/5/2012
9
Question: 3. The conce concep pt of the ……. al allows deferral rral of mainte ntenance nce without upsetting the mission requirements. 1. LRU 2. Reliability 3. MEL aintena nance nce program 4. M ainte 4. MMEL MM EL iss issue by rl ine and approved pproved by authority uthority 1. A irli anufacture acturerr and and approved approved by state of manuf anufacture acturerr 2. M anuf desiigne gnerr and approv pproved ed by state of des desiign 3. des rl ine and approved pproved by state state of desi design 4. A irli 19
Question: 5. A compone ponent or system that that has bee been design signe ed in in such a manner that the parts parts that most com commonly only fai faill can be quickl quickly y rem removed and repl replaced on the the vehi vehicl cle e refe refer to as: 1. MEL CDL 2. CDL 3. LRU 4. MMEL 6. The designe signed-in level of perf perfe ection is is known known as tthe he: nherent rent rel reliabili bil ity 1. I nhe 2. Ultra safe design pproved de design sign 3. A pproved 20 edundant nt design sign 4. Redunda
Maintenance management
By m.shahbazi
4/5/2012
10
Question: 5. A compone ponent or system that that has bee been design signe ed in in such a manner that the parts parts that most com commonly only fai faill can be quickl quickly y rem removed and repl replaced on the the vehi vehicl cle e refe refer to as: 1. MEL CDL 2. CDL 3. LRU 4. MMEL 6. The designe signed-in level of perf perfe ection is is known known as tthe he: nhe ere rent nt re relliabil biliity 1. I nh 2. Ultra safe design pproved de design sign 3. A pproved 21 edundant nt design sign 4. Redunda
Maintenance management
By m.shahbazi
4/5/2012
11
