mission readiness analysis and related reliability and maintenance requirement allocation Functional system failure analysis and derived requirements specification Inherent (system) design reliability analysis and derived requirements specification for both hardware and software design System diagnostics design Fault tolerant systems (e.g. by redundancy) Predictive and preventive maintenance (e.g. reliability-centered maintenance) Human factors / human interaction / human errors Manufacturing- and assembly-induced failures (effect on the detected "0-hour quality" and reliability) Maintenance-induced failures Transport-induced failures Storage-induced failures Use (load) studies, component stress analysis, and derived requirements specification Software (systematic) failures Failure / reliability testing (and derived requirements) Field failure monitoring and corrective actions Spare parts stocking (availability control) Technical documentation, caution and warning analysis Data and information acquisition/organisation (creation of a general reliability development hazard log and FRACAS system) Chaos engineering Effective reliability engineering requires understanding of the basics of failure mechanisms for which experience, broad engineering skills and good knowledge from many different special fields of engineering are required, for example: Tribology Stress (mechanics) Fracture mechanics / fatigue Thermal engineering Fluid mechanics / shock-loading engineering Electrical engineering Chemical engineering (e.g. corrosion) Material science Definitions Reliability may be defined in the following ways: The idea that an item is fit for a purpose with respect to time The capacity of a designed, produced, or maintained item to perform as required over time The capacity of a population of designed, produced or maintained items to perform as required over time The resistance to failure of an item over time The probability of an item to perform a required function under stated conditions for a specified period of time The durability of an object Basics of a reliability assessment Many engineering techniques are used in reliability risk assessments, such as reliability block diagrams, hazard analysis, failure mode and effects analysis (FMEA), fault tree analysis (FTA), Reliability Centered Maintenance, (probabilistic) load and material stress and wear calculations, (probabilistic) fatigue and creep analysis, human error analysis, manufacturing defect analysis, reliability testing, etc. It is crucial that these analyses are done properly and with much attention to detail to be effective. Because of the large number of reliability techniques, their expense, and the varying degrees of reliability required for different situations, most projects develop a reliability program plan to specify the reliability tasks (statement of work (SoW) requirements) that will be performed for that specific system. Consistent with the creation of safety cases, for example per ARP4761,