What should be avoided when extinguishing an APU fire?

Using a CO2 extinguisher directly on the APU is something that should be avoided when extinguishing an APU fire because CO2 is not as effective on certain types of fires, particularly those involving components that may continue to burn even after being sprayed. Direct application can also result in a quick dissipation of the CO2, which may not smother the fire effectively due to airflow or combustion issues around the unit. In such situations, the risk of re-ignition is higher, and proper extinguishing methods must be employed to ensure the fire is completely out.

It's crucial to understand alternative fire-fighting methods and the characteristics of the APU's components when dealing with such incidents. Other responses, including proper ventilation and ensuring that personnel are out of harm's way, play critical roles in the effectiveness of fire-fighting efforts. These aspects help minimize risks and protect everyone involved in emergency situations.