RMQSI Answers ForumCategory: Handbooks and StandardsNPRD 95 Failure Rate Questions
jesse_blair asked 11 years ago

I have been using NPRD-95 to assign failure rates and have several questions. Please feel free to address as few or as many questions as you desire. I am in the aircraft hydraulics industry so most of our components are purely mechanical.

Miles / Hours Conversion Factor?
Often failure rates are given in terms of failures per million miles. I have been unable to find a conversion factor from miles to hours, and it appears that the industry uses them interchangeably (e.g. even though an analysis is done in failures / hrs it will still use failures / miles rates without using a conversion factor). Is my assessment correct?

Quality / Environmental Conversion Factors
Quality / Environmental conversion factors are given in Rome Laboratory Reliability Engineer