What should be done when the source of fire is unknown?

• A. Treat as fire, isolate the area, inform the flight deck, and be prepared for possible evacuation
• B. Ignore until verified
• C. Try to identify source first
• D. Evacuate everyone immediately without assessment

Answer: (A)

When the source of a fire is unknown, you must act as if a fire is present. This conservative approach is essential because conditions in an aircraft can deteriorate quickly and you may not know where the fire is or how fast it’s spreading. Treating it as fire means taking immediate protective actions: isolate the area to prevent the fire and smoke from moving to other compartments, which helps limit damage and keeps adjacent zones safer. Inform the flight deck right away so the captain can coordinate the response, adjust cockpit procedures, and decide on the need for evacuations or further action. Finally, be prepared for possible evacuation because the situation can change in moments, and having passengers and exits ready allows a rapid, orderly escape if it becomes necessary. Waiting to verify or trying to locate the source first wastes time and can let the situation worsen, and evacuating without assessment can cause unnecessary disruption if the risk is not yet immediate.