Lavatories surveillance requires the smoke detection system to be operational and unobstructed. What is the minimum interval for lavatories surveillance?

• A. 10 minutes
• B. 15 minutes
• C. 60 minutes
• D. 30 minutes

Answer: (B)

Lavatories surveillance is about keeping the lavatory smoke detection system in the lavatories both operational and unobstructed. Checking at least every 15 minutes ensures that any change—like a detector becoming blocked or a failing component—is caught promptly, enabling quick action if smoke is present.

This interval strikes a balance between safety and the crew’s workload. A 10-minute check would be unnecessarily frequent and add to workload without proportional safety benefit. Checks every 30 or 60 minutes could allow unnoticed issues to go longer, increasing the risk of delayed smoke detection.