What is a function of the LAV smoke button on the FAP?

The function of the LAV smoke button on the FAP, which is correctly identified as illuminating during a smoke detection, is crucial for ensuring passenger safety and facilitating effective emergency response in instances of smoke or fire in the lavatory area of an aircraft. When activated, the smoke button serves as a visual alert to the flight crew, indicating that smoke has been detected. This prompt notification allows the crew to assess the situation quickly and take appropriate actions, such as deploying firefighting measures or preparing for an emergency evacuation if necessary.

The illumination provided by the smoke button ensures that even in low-visibility situations, the crew can readily identify the source of concern and respond accordingly. Hence, the functionality of the smoke button is central to the overall safety mechanisms in place, emphasizing the importance of swift communication during critical incidents onboard an aircraft.