Model‐Based Analysis of Standard Operating Procedures' Role in Abnormal and Emergency Events

Abstract

AbstractStandard Operating Procedures (SOP) describe the desired flight‐crew response to mission events including normal, abnormal, and emergency events. The SOPs define flight‐crew step‐by‐step actions to perform the SOP appropriate for the mission event. Although the aircraft and automation are tested rigorously for certification, and the flight‐crew are trained and qualified through simulator and flight check‐rides, oversight of the SOPs is marginal. This is especially problematic for SOPs that must be completed in a short Allowable Operational Time Window (AOTW) prior to the occurrence of a hazardous event. The AOTW can be variable due to environmental conditions (e.g. wind, aircraft performance), as is the Time‐on‐Procedure (ToP) (e.g. simultaneous procedures/events, disruptions/distractions in the cockpit, variability in individual human performance). The variance motivates the need for modeling and analysis of SOPs.This paper used a modeling language embedded in a System Engineering Model‐Based tool to evaluate the execution performance of the SOPs for abnormal/emergency mission events with regard to ToP and AOTW. The analysis yielded a classification of the accident scenarios by: (1) Insufficient AOTW, (2) Excessive ToP, or (3) combination of excessive ToP and insufficient AOTW. For the excessive ToP, the analysis highlighted the issue of delay in initiating an SOP due to ambiguity in the triggering cue from the external environment, or missing associations between a cockpit alert and the SOP. The analysis also highlighted issues arising from the presence of memory items in the SOP, or cues that are out of the operator's Field of View (FoV). In all cases, the results highlighted the importance of a method for quantifying the performance of SOPs considering the variability in ToP and AOTW. The implications of these results are discussed.