Which of the following is NOT an indication of fire?

Passenger complaints are more about subjective experiences rather than objective indicators of a fire. While passengers may report seeing smoke or detect an unusual odor associated with a fire, their complaints alone do not provide concrete evidence of a fire situation. The focus of emergency evacuation and response procedures is generally on specific, measurable signs of fire incidents.

In contrast, the activation of a lab smoke detector, the presence of hot spots indicative of overheating, and a popped circuit breaker, which may signify electrical issues or possible fire hazards, are all more direct indicators of a fire or fire risk. These indicators can trigger immediate safety protocols to protect everyone on board and assess the situation properly.