This chapter presents a case study that involves the use of propositional networks to describe and analyse situation awareness during a recent high-profile friendly fire incident. The analysis identifies the different types of Safety Analysis (SA)-related failures involved in the friendly fire incident with a view to informing future prevention efforts. The official UK Army inquiry into the incident identified various causal factors, including planning, oversights, communications failures, failures in command and control, lack of SA, incorrect target identification, inadequate tactics, techniques and procedures, fog of war, and fatigue. The propositional network methodology was used to model situation awareness throughout the scenario, with a view to identifying the situation awareness failures that contributed to the incident. One analyst with significant experience in the propositional network method constructed the network based on content analysis of the incident description presented within UK MoD's Army board of inquiry report.