How does the engine fire detection system operate?

The engine fire detection system operates primarily by detecting a drop in resistance caused by an overheat condition, making this choice the correct one. This system typically uses wires or sensing cables that change their electrical resistance in response to heat. When the temperature reaches a certain threshold due to a potential fire or overheating situation, the resistance in the sensing element drops, triggering an alarm or warning system to alert the crew of the potential fire risk.

This operational principle is crucial for ensuring prompt identification of fire hazards, enabling timely responses to prevent further damage or catastrophe. The detection system's design allows for early detection of dangerous conditions, enhancing safety during flight operations.

In contrast, while monitoring fuel flow is important for evaluating engine performance, it does not directly indicate fire conditions. Similarly, sensing smoke particles could be effective in certain scenarios, but standard engine fire detection typically relies on changes in resistance due to overheating rather than smoke. Detecting a rise in pressure is also not a method used for fire detection but is relevant in other contexts within engine monitoring systems.