What will occur if the APU detects a fire during flight?

When the APU detects a fire during flight, the appropriate response is for the APU to automatically shut down to prevent the potential spread of the fire and protect the aircraft and its occupants. Option B accurately describes what should happen, which is that the APU will shut down and the fire bottle will discharge to extinguish any flames. This response is crucial because it minimizes the risks associated with an in-flight fire, ensuring the safety of the aircraft.

The fact that the APU will shut down is a critical safety measure designed to prevent further complications that might arise from continuing its operation in the presence of a fire. However, the discharge of the fire bottle is an equally important step that follows the shutdown. Understanding this sequence highlights the safety mechanisms in place for dealing with in-flight anomalies involving the APU.

Correctly grasping this process is vital for crew members to act swiftly and safely in emergencies. Therefore, the identification of the fire detection and corresponding actions are directly related to the mission of maintaining safety standards in aviation operations.