What is fault tree analysis? Fault tree analysis (FTA) is a top-down approach to failure analysis, starting with a potential undesirable event (accident) called a TOP event, and then determining all the ways it can happen. ? The analysis proceeds by determining how the TOP event can be caused by individual or combined lower level failures or events. ? The causes of the TOP event are connected through logic gates ? In this book we only consider AND-gates and OR-gates ?