Methods for predicting technical reliability of commercial aircraft
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Helsinki University of Technology |
Diplomityö
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Date
2008
Department
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Lentotekniikka
Mcode
Kul-34
Degree programme
Language
en
Pages
xii + 91 s. + liitt. 18
Series
Abstract
In this thesis, qualitative and quantitative methods to predict technical reliability of commercial aircraft are studied. The scope is to survey the current reliability program in Finnair Plc, to perform a dependency analysis, and to propose methods to predict aircraft technical reliability. The study is based on a literature review, interviews, and data analysis. Authority requirements are taken into account as well. The literature review revealed few quantitative methods suitable for reliability applications. However, most of them are relatively complex. No comprehensive studies of qualitative reliability prediction were found. Based on the literature review, the link between economical aspects and dispatch reliability is very strong. In the interviews, it is found that the current reliability program and reliability organization of Finnair Plc require consolidation. Furthermore, the reporting is performed simultaneously in different departments producing extra work and non-uniform analysis. Data analysis is performed to find out the relationships between different variables and technical reliability. The variables under analysis are workload of maintenance organization, route structure, aircraft age and utilization, number of defect reports, effect of component design philosophy, removal reasons, and no-fault-found rate. The analysis is based on standard probability and statistical methods. As a result of the study, qualitative and quantitative methods for predicting technical reliability at the target company are proposed. As a qualitative method a reliability control process is described and the required organization given. Furthermore, an overview of ATA Spec 2000 reporting standard is given. As a quantitative prediction method a component life cycle model is proposed. It is based on the two-parameter Weibull distribution. With the proposed method and simulated utilization it is possible to estimate the reliability trend of the installed components.Description
Supervisor
Saarela, OlliThesis advisor
Hakala, MarkusKeywords
aircraft, reliability, Weibull Distribution, delay, reliability program