How to react to an unexpected and challenging situation that has never been thought of before it happened? A situation for that no checklist exists and no training could be performed? The EU-funded project Man4Gen, Manual Operations of 4th Generation Airliners, which has been successfully completed in 2016, employed human-in-the-loop simulation as an e�ective tool used to analyze the crew response in unexpected and ambiguous
situations. Based on an exploratory simulator study on the crews' behavior during these situations the so-called Risk Information System was developed to support crews in their decision-making and problem solving. The paper gives an overview of the conduction and results of the exploratory simulator study leading to the development of the Risk Information System. The system's new philosophy of displaying failures is explained and the results of its proof-of-concept evaluation are shown.