What is the main difference between an FMEA and an FTA?

The primary distinction between FMEA (Failure Mode and Effects Analysis) and FTA (Fault Tree Analysis) lies in their approaches to analyzing failures. FMEA is a bottom-up approach that starts by examining individual components to identify potential failure modes, their causes, and the effects these failures could have on the overall system. This method systematically evaluates each element in order to prioritize risks based on their severity and likelihood of occurrence.

In contrast, FTA utilizes a top-down approach where the analysis begins with the identification of a specific undesired event or system failure at the top of a fault tree. The tree is then developed by breaking down the event into its potential causes, often represented visually. This method focuses on understanding how different failures can contribute to the top-level event.

Overall, the correct understanding emphasizes the directional flow of each analysis method—FMEA systematically investigates from the micro level while FTA works down from a broader perspective, examining system failures in relation to their contributing factors.