Investigating flight crew strategies to cope with unexpected events: a multi-layered extended control model of joint crew-automation activity

Although commercial aviation is a highly standardized and ultra-safe industry, there are still times when the flight crew are faced with an unexpected situation, and must respond appropriately. This article studies how to characterize variability in flight crew strategies handling unexpected events, problematic as well as successful. Hollnagel’s Extended Control Model (ECOM) is operationalized as an analysis tool for crew-automation Joint Cognitive System (JCS) performance, for simulated B747 and A330 scenarios, as well as more generally for joint activity of crew and automation in airliner cockpits. This development and application of ECOM to two studies in a research flight simulator is described, highlighting crew-automation JCS performance at multiple layers of control. The ECOM analyses are found to be in unison with industry expert ratings, while providing a more nuanced qualitative perspective supporting pattern identification. Various process-tracing visualizations of flight crew strategies in terms of performance at the various ECOM layers illustrate patterns. ECOM and related Contextual Control Model (COCOM) classifications and assessments contribute to the explanation of performance and as a rich qualitative description of desirable performance. Frequent and regular interaction between ECOM layers and tactical/strategic control modes correspond to desirable performance. Recommendations to the aviation industry for preparing pilots better for unexpected events are outlined.