When is a yellow disk ejected related to the fire extinguisher system?

A yellow disk is ejected from a fire extinguisher system as a clear visual indication that the system has been activated by the flight crew. This mechanism is designed to signal that the fire suppression agent has been discharged, which often happens in emergency situations. The visible ejection of the yellow disk serves as a status indicator, allowing crew members and maintenance personnel to quickly identify whether the system has been utilized.

In contrast, the other options do not correlate with the function of the yellow disk. For instance, during system inspections or refills, there would not necessarily be an activation and thus no disk ejection. Similarly, a system malfunction would not normally result in the intentional ejection of the disk; rather, it usually involves a failure to operate correctly. Thus, the key function of the yellow disk is tied specifically to the intentional activation of the fire extinguisher by the flight crew, marking the moment the fire suppression system has been engaged.