Table Of Content2006:18 HIP
BACHELOR’S THESIS
Maintenance and Reliability
With Focus on Aircraft Maintenance
and Spares Provisioning
JOHAN WIKSTÉN
MARCUS JOHANSSON
B. Sc. PROGRAMME
Aeronautical Engineering
Luleå University of Technology
Department of Civil and Environmental
Division of Operation and Maintenance
2006:18 HIP (cid:129) ISSN: 1404 - 5494 (cid:129) ISRN: LTU - HIP - EX - - 06/18 - - SE
SAMMANFATTNING
Den här rapporten är ett resultat av det examensarbete som utförts i ämnet
underhållssäkerhet, med sina relaterade områden. En ingående studie i logistisk
support företogs också, för att fördjupa förståendet av dess roll i, och hur detta
påverkar, underhålls procedurerna. Då ämnet underhåll är stort, har fokus lagts på att
undersöka möjligheten att med hjälp av befintliga arkiv, förbättra underhålls
procedurerna och i viss mån även reservdelsförsörjningen. Arbetet gäller underhålls
procedurer inom flygindustrin och har utförts i enlighet med gällande regler och
föreskrifter från luftfartsmyndigheten.
Arbetet har utförts på Avdelningen för Operation and Maintenance Enginering vid
LTU, under en tio veckors period vårterminen 2006. Uppdragsgivare var Luleå
Flygteknik, som tillhandahöll material och expertis inom flygunderhåll och dess
procedurer. Författarna vill här ta tillfället i akt att tacka alla som på ett eller annat sätt
bidragit till, eller medverkat, i arbetet. Ett speciellt tack tillskrivs följande personer för
deras medverkan och för delgivandet av expertis och kunskaper under arbetets gång,
dessa personer är: Prof. Uday Kumar (examinator LTU), Aditya Parida (handledare
LTU), Arne Nissen (Adjunkt LTU) och Jan Viklund (uppdragsgivare och handledare
LFT).
Luleå Maj 2006
Johan Wikstén Marcus Johansson
SUMMARY
This report is the result of a study performed on maintenance reliability and, its,
related issues. Studies of logistic support issues have also been performed to
understand its important role in maintenance practice. Due to the extensive topics of
maintenance, the focus in this study has been set to the investigation of the
possibilities to make use of existing records for improvement in maintenance
procedures and in some manner, also spare parts provisioning. The study focuses on
the maintenance procedures in the aviation industry and, has been carried out in
accordance with aviation regulating authority.
The study has been performed at the Division of Operation and Maintenance
Engineering at Luleå University of Technology (LTU) during ten weeks in the spring
semester of 2006. Sponsor for the study was Luleå FlygTeknik (LFT) which provided
material and expertise in aviation maintenance and its procedures.
The authors wish to thank every person who has, in one way or another, been
contributing or involved in this study. A especially thank you, are directed to the
following persons for their participation and for sharing their expertise during the
study, they are: Prof. Uday Kumar (examiner LTU), Aditya Parida (supervisor LTU)
and Jan Viklund (sponsor and supervisor LFT).
Luleå May 2006
Johan Wikstén Marcus Johansson
ABBREVIATIONS AND EXPLANATIONS
AMP Aircraft Maintenance Plan
ATA Air Transportation Association of America
EASA European Aviation Safety Agency
FFOP Failure Free Operating Period
FMEA Failure Mode and Effect Analysis
LFT Luleå FlygTeknik
MDT Mean Down Time
MFOP Maintenance Free Operating Period
MLDT Mean Logistic Delay Time
MMH Maintenance Man Hour
MPD Maintenance Plan Document
MRB Maintenance Review Board
MSG Maintenance Steering Group
MTBCF Mean Time Between Critical Failure
MTBF Mean Time Between Failure
MTBM Mean Time Between Maintenance
MTBO Mean Time Between Overhaul
MTBUR Mean Time Between Unscheduled Removal
MTTF Mean Time To Failure
MTTR Mean Time To Repair
PART A sub part of EASA regulation document
RCM Reliability Centered Maintenance
TFh Total Flight hours
VAT Value Added Tax
CHAPTER 1 1
INTRODUCTION 1
1.1 BACKGROUND 1
1.2 PROBLEM STATEMENT 2
1.3 PURPOSE 2
1.4 AIM 2
1.6 SCOPE AND LIMITATIONS 2
1.7 METHODOLOGY 2
CHAPTER 2 4
LITERATURE STUDIES AND INTERVIEWS 4
2.1 RELIABILITY 4
2.1.1 PROBABILITY THEORY 4
2.1.2 PROBABILITY/RELIABILITY DISTRIBUTION 5
2.1.3 RELIABILITY MEASUREMENTS 6
2.1.4 FAILURE FUNCTION 6
2.1.5 RELIABILITY FUNCTION 7
2.2 MAINTENANCE 8
2.2.1 MAINTAINABILITY AND ITS CONCEPTS 9
2.2.2 MAINTAINABILITY MEASUREMENTS 9
2.2.3 MAINTENANCE AND ITS CONCEPTS 10
2.2.4 MAINTENANCE COST 12
2.3 OPTIMIZATION OF MAINTENANCE 13
2.3.1 PREVENTIVE MAINTENANCE AND RELIABILITY 13
2.3.2 MSG3, RELIABILITY CENTERED MAINTENANCE 15
2.3.3 RCM PROCESS 16
2.4 LOGISTICS 19
2.4.1 HISTORY 19
2.5 INTEGRATED LOGISTIC SUPPORT 19
2.5.1 MAINTENANCE PLANNING 20
2.5.2 SUPPLY SUPPORT 20
2.5.3 SUPPORT AND TEST EQUIPMENT 21
2.5.4 MANPOWER AND PERSONNEL 21
2.5.5 TRAINING AND TRAINING DEVICES 22
2.5.6 TECHNICAL DATA 22
2.5.7 COMPUTER RESOURCES SUPPORT 23
2.5.8 HANDLING, STORAGE, AND TRANSPORTATION 23
2.5.9 FACILITIES 24
2.5.10 DESIGN INTERFACE 24
2.6 AVIATION LOGISTICS 24
2.7 INTERVIEWS 25
CHAPTER 3 27
AUTHORITY REGULATIONS 27
3.1 CERTIFYING AUTHORITY 27
3.2 MAINTENANCE REVIEW BOARD (MRB) 29
3.3 AIRCRAFT MAINTENANCE PROGRAM (AMP) 30
CHAPTER 4 31
MAINTENANCE TASK COMPILING 31
4.1 MAINTENANCE TASK COMPILING 31
4.2 SAMPLE AIRCRAFT FLEET 32
4.3 DETERMINE THE SCHEDULED MAINTENANCE 32
4.4 DETERMINE THE UNSCHEDULED MAINTENANCE 32
4.5 MAINTENANCE DATA ANALYSIS 34
4.5.1 ANALYSIS OF FAILURE OCCURRENCE 34
4.5.2 ANALYSIS OF PREVENTIVE MAINTENANCE 35
CHAPTER 5 38
DISCUSSION 38
5.1 ANALYSIS REFLECTIONS 38
5.2 LOGISTIC SOFTWARE 40
5.3 SPARES PROVISIONING OPTIMIZATION 40
5.3.1 ANALYSIS OF PREVIOUS EXAMPLES 41
CHAPTER 6 42
RECOMMENDATIONS 42
CHAPTER 7 43
CONCLUSION 43
CHAPTER 8 44
REFERENCES 44
8.1 LITERATURE 44
8.2 WEB 45
APPENDIX 46
Chapter 1
INTRODUCTION
1.1 Background
Maintaining a repairable system can be a complex task from economical and
reliability point of view. High reliability is most essential which may not be connected
with high costs. Due to the multidisciplinary characteristic of maintenance which
consists of management planning, equipment, facilities, inventory and human
resources, it is hard to overview and manage the maintenance tasks. If a system is not
maintained correctly, it will sooner or later cease to perform its required function with
loss of safety and availability, besides reliability which will lead to several losses like
economical, structural and in the worst case fatal injuries to humans.
Within the aviation industry, the operational requirements are high and because of the
consequences of failure, the maintenance procedures governed by strict legislation
under strict directive from regulating authority. These directives are developed in a
structured way of national requirements like international safety standards. The
scheduled maintenance of an aircraft contains hundreds of timely/cyclic based
inspections and replacements of parts. These can be divided into about 40, or more,
groups with different periodic intervals, which are developed from maintenance
strategy like MSG3. Even if a system is maintained, deviations will occur, these
deviations must be considered separately since they have a tendency to occur
randomly at times and these are the unscheduled maintenance tasks. All implemented
maintenance tasks, scheduled as well as unscheduled, must be recorded and archived.
For small and medium companies, it seems like this information is rarely used to
improve the organization. Even if there are already developed software’s available on
the market, which takes care of probability calculations of failures and spare part
optimization, the burden of license fees is too high for the small and medium
maintenance organizations to justify the use of these. Savings can be made by using
the knowledge of previous maintenance data, although the use of an adopted software
would be more effective, a simpler and cheaper analytic method can improve the
logistic tasks like maintenance planning, spares, etc, and will also affect positively on
aircraft availability and unpredicted expenses.
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