What is the primary function of pressing the AFT cargo smoke push button?

The primary function of pressing the AFT cargo smoke push button is to activate the fire suppression system in the aft cargo area. This action is critical in the event of smoke detection, as it initiates measures to control and address potential fire hazards effectively. The system is designed to release agents that can help extinguish fires, thereby enhancing safety for both the aircraft and its occupants.

While other options pertain to related systems, they do not encompass the primary purpose of the button. For instance, closing the air conditioning shut-off valve might help in managing airflow, but it does not directly engage the fire suppression measures crucial in a smoke scenario. The illumination of the AFT cargo smoke warning light serves to alert crew members of the situation but is not the essential action performed by pressing the button. Similarly, opening the cargo doors would not address the need to suppress smoke or fire and could potentially exacerbate danger. Thus, the function of activating the fire suppression system is paramount when addressing smoke detection in the cargo area.