What is the black box mounted to side of an engine do?

The black box mounted to the side of an engine is typically an aircraft's flight data recorder (FDR) or cockpit voice recorder (CVR). These devices continuously record critical flight data and cockpit audio, capturing information such as altitude, speed, and engine performance, as well as conversations between pilots. In the event of an accident, the data stored in these black boxes is crucial for investigations to determine the causes and contributing factors.