What is a clear external indication of an engine fire?

An engine fire is characterized by visible flames or intense heat, and a clear external indication of this situation is fire coming out of the exhaust. When an engine experiences combustion outside of the controlled environment, such as flames shooting from the exhaust, it is a definitive sign that something is wrong, often indicating a serious emergency that requires immediate action.

While smoke in the cockpit, unusual engine noises, and flashing warning lights could indicate various issues or malfunctions, they are not specific external signs of an engine fire. Smoke in the cockpit could stem from multiple sources, unusual noises can result from many engine performance issues, and warning lights are general indicators that may point to different malfunctions, not explicitly an engine fire. Therefore, the presence of flames escaping from the exhaust stands out as a clear and unmistakable sign of an engine fire.