Can both fire extinguisher containers be discharged into the APU when required?

The correct response indicates that only bottle number two can be discharged into the Auxiliary Power Unit (APU). This distinction is important because fire extinguisher systems are designed with specific operational protocols that govern the use of each bottle. In many aircraft systems, the fire suppression resources are compartmentalized to enhance safety and effectiveness, and only designated components are meant to interact with specific systems, such as the APU.

Selecting bottle number two for discharge into the APU suggests that there is a reason for this specific designation, which might stem from operational pressures, chemical formulations, or the manner in which the extinguishing agent is released. This careful design ensures that fire suppression is executed effectively, optimizing the aircraft's safety protocols. Understanding the operational limits of the fire suppression system is vital for instructors, as it enables them to teach proper emergency procedures and ensure compliance with safety regulations.