Thanx grounded27
My experience with fire loops is quite limited, but my memory is;
1. With dual podded engines there have been several accidents where one engine failed and the wrong engine shutdown due to interpretation of the fire alarm. B52, B1, etc.
2. Smoke in cockpit from an engine fire that was not detected due to fireloop placement only near hot section
3. Fireloops that no longer function when the engine nacelle leaves, but the fire remains.
4. Fires that spread to composite reverser cascades on the ground that are difficult to detect and extiniguish