Product Code:SAE ARD50010 Title:Recommended Rms Terms and Parameters Issuing Committee: Scope: The terms used in most engineering technologies tend to be physical characteristics such as speed-rate of turn and fuel consumption. while they may require very careful definition and control of the way in which they are measured, the terms themselves are not subject to different interpretations. Reliability, Maintainability and Supportability (RMS) however, use terms that are mathematically defined. As a result, there are more than 200 terms defined in just the documents reviewed so far, many of which have multiple interpretations. This proliferation of definitions of the terms leads to problems when one attempts to compare the performance of one system to another. For example, the RMS performance of a transport aircraft from the commercial arena is measured using metrics that are not the same as those for a fighter or attack aircraft from a military service. It is accepted that some of the metrics may be unique because of the nature of the missions, but is the strong conviction of the Government and Industry practitioners who make the SAE G11 committee that there should be some fundamental definitions used for all systems.