ADS-79D-HDBK Downloaded from https://www.everyspec.com P-F Interval: The period between the point at which a potential failure becomes detectable and the point at which it degrades into a functional failure. (SAE JA1011) Prevalence: Prevalence is defined as the fraction of defectives in a given population at a specific time. Protective Device or Protective System: A device or system which is intended to avoid, eliminate, or minimize the consequences of failure of some other system. (SAE JA1011) Potential Failure: An identifiable condition that indicates that a functional failure is either about to occur or is in the process of occurring. (SAE JA1012, SAE JA1011) Precision:
A measure of narrowness of dispersion associated with the predicted results for multiple experiments. Primary Function(s): The function(s) which constitute the main reason(s) why a physical asset or system is acquired by its owner or user. (SAE JA1011, SAE JA1012) Proactive Maintenance : Maintenance undertaken before a failure occurs, in order to prevent the item from getting into a failed state (scheduled restoration, scheduled discard, and on-condition maintenance). (SAE JA1012) Positive Predictive Value (PPV): The probability that a part actually has defect if sensor indicates a positive result. (MIL-HDBK 1823) Negative Predictive Value (NPV):
The probability that a part is defect-free if sensor indicates a negative result. (MIL-HDBK 1823) Prognostics: Identifies predictable periods of operation free of functional failures with an estimate of time to failure, maintenance action, or remaining useful life. Reliability Centered Maintenance (RCM): A process to ensure that assets continue to do what their users require in their present operating context. (ADS-79D) RCM is a specific process used to identify the policies which must be implemented to manage the failure modes which could cause the functional failure of any physical asset in a given operational context. (SAE JA1011) Robustness:
A measure of capability to perform intended functions without failure under a wide range of conditions specified. Run-to-Failure: A failure management policy that permits a specific failure mode to occur without any attempt to anticipate or prevent it. (SAE JA1011) Safety Consequences: A classification of failure modes that could injure or kill a human being. (SAE JA1011) 188