Systemic safety analysis of complex socio-technical events: Insights from applying causal analysis based on systems theory and functional resonance analysis method

Understanding safety in complex socio-technical systems requires analytical approaches that move beyond linear accident models to examine how interactions across organisational, technical and operational elements shape safety outcomes. This study applies two systemic safety analysis approaches, Causal Analysis based on Systems Theory (CAST) and the Functional Resonance Analysis Method (FRAM), using well-documented aviation investigation data. The study examines how different systemic methods model system behaviour, frame causality and performance variability, and generate different forms of safety recommendations. CAST identified cross-level control and feedback weaknesses that enabled the wrong-surface alignment under the runway-closure night configuration. FRAM showed how coupled performance variability, including missed runway-closure cueing and ambiguous visual cues, shaped the development of misalignment risk while also clarifying the recovery pathway that enabled the go-around. This study suggests that CAST and FRAM are best used as complementary lenses for systemic event analysis. CAST supports governance and assurance redesign, while FRAM informs operational guardrails and variability management under uncertainty.