Analyzing Standard Operating Procedures Using Model‐Based Systems Engineering Diagrams

• Published in: INCOSE International Symposium Vol. 31; no. 1; pp. 1130 - 1144
• Main Authors: Bashatah, Jomana A., Sherry, Lance, Dam, Steve, Flenniken, Lauren, Hartmann, Patrick, Harold, Tom
• Format: Journal Article
• Language: English
• Published: 01.07.2021
• ISSN: 2334-5837; 2334-5837
• DOI: 10.1002/j.2334-5837.2021.00891.x

Standard Operating Procedures (SOPs) are critical for the safe operations of complex, hazard‐sensitive systems. The SOPs are particularity important for dealing with non‐normal operations in which the human operator must intervene and/or provide instructions to the automation. Under these rare circumstances, the appropriate human operator actions are defined by SOPs. The SOPs must be completed within an Allowable Operational Time Window (AOTW) to avert a hazardous outcome. In many cases, the AOTW is not fixed, but exhibits variance due to complex non‐linear, plant dynamics. The Time on Procedure (ToP) is also subject to variability due to human factors such as experience, proficiency, fatigue, and the efficacy of the SOPs and the supporting automation user‐interface. For this reason, it is critical to evaluate the dynamic performance of the SOP in the context of the operations and determine the likelihood of the ToP exceeding the AOTW. This paper describes how to model SOPs and perform SOP analysis using LML/SysML Action/Activity Diagrams that can be found in most Model‐based System Engineering (MBSE) tools. The method enables the SOP designer to assess the performance of the SOP by accounting for human factors and operation dynamics. The ability to test the procedures in a MBSE tool can inform the system design and verify the procedure design early in the development life‐cycle. The implications and limitations of this approach are discussed.