Engineering Reliability and Risk Management

Risk-based thinking (RBT) is now an even more prominent part of every ISO Management System, and is employed in many of the requirements of AS9100D Aerospace standards. Risk management is a requirement in several clauses of the AS9100D, and is mandatory based on ISO 31000:2018 which provides generic guidelines and frameworks to risk management processes. 

Reliability is the probability that the system of interest will not fail for a given period of time under specified operating conditions. Reliability is an inherent system design characteristic. Reliability plays a key role in determining the system’s cost effectiveness. Reference: NASA Systems Engineering Handbook 

Reliability engineering is the discipline of ensuring that a system will function as required over a specified time period when operated and maintained in a specified manner. As per IEEE standards, reliability is defined as the ability of a system or component to perform its required functions under stated conditions for a specified period of time .” The key elements of the definition are ability, required function, conditions , and specified period of time .

  • Ability is expressed quantitatively with probability .
  • Required function relates to expected performance.
  • Stated conditions usually refer to environmental conditions of operation.
  • Specified period of time is also referred as mission time which provides expected duration of operation.

Failure modes and effects analysis (FMEA) is an established semi-qualitative reliability engineering approach to systematically evaluating system design on a component-by-component basis to identify failure modes and their effects on system function and other system components. 

ASQ Reliability Tools



Cause and Effect Analysis (FISHBONE DIAGRAM)