| Abstrakt: |
The test results of the removed aircraft components are classified into No Fault Found (NFF), Real Reason Conform (RRC) and Other Defect Found (ODF). Corrective actions will be taken on findings that are classified as RRC and ODF, while for the NFF category no action will be taken. In the MRO XYZ, for the NFF category, the age of the component during the removal is included into the failure data. Moreover, the reliability calculation in the MRO XYZ uses the 2-parameters Weibull distribution. These will result in unrepresentative reliability calculation. Therefore, it is necessary to evaluate the method. The research compares the results of the reliability calculation between the 2-parameters and the 3-parameters Weibull distributions by applying them to several part numbers data. Furthermore, the reliability calculation using the 3-parameters Weibull is also applied to the data where the NFF category is not included the failure data. The location parameter, g, is calculated using the Muralidhar method. The research also develops an excel VBA macro-based tool for reliability calculation. The results of the reliability calculation show that there is a significant difference of the failure rate between using the 2-parameters and the 3-parameters Weibull distribution. The failure rate calculated by using the 3-parameters Weibull distribution for the data where NFF category is not included into the failure data show a significant different as compared to the method used by the MRO XYZ, where the difference is affected by the percentage of NFF items in the failure data. |
