Which door state is listed as a shutdown criterion for the APU?

Which door state is listed as a shutdown criterion for the APU?

• A. Door Closed
• B. Door Open
• C. Door Ajar
• D. Door Latch

Answer: (A)

The concept here is that physical door positions act as safety interlocks for the APU. The control system watches the door state and will stop the APU if the door ends up in a position that would compromise safe operation. When the door is closed, it can block the required airflow for cooling and proper exhaust flow. That blockage can lead to overheating or other unsafe conditions, so the system automatically initiates a shutdown to protect the APU. So, identifying door closed as a shutdown criterion reflects the safety logic: a closed door during operation signals an unsafe condition, triggering shutdown. In other contexts, open or ajar states might indicate that startup isn’t possible or that a fault is present, but the specific criterion described here is that the closed state prompts shutdown.

The concept here is that physical door positions act as safety interlocks for the APU. The control system watches the door state and will stop the APU if the door ends up in a position that would compromise safe operation. When the door is closed, it can block the required airflow for cooling and proper exhaust flow. That blockage can lead to overheating or other unsafe conditions, so the system automatically initiates a shutdown to protect the APU.

So, identifying door closed as a shutdown criterion reflects the safety logic: a closed door during operation signals an unsafe condition, triggering shutdown. In other contexts, open or ajar states might indicate that startup isn’t possible or that a fault is present, but the specific criterion described here is that the closed state prompts shutdown.