Extinguishing an APU fire is accomplished through the use of which bottle?

• A. The single halon fire bottle dedicated to the APU
• B. The main extinguishing bottle in the cockpit
• C. A water mist system
• D. A portable handheld extinguisher

Answer: (A)

Extinguishing an APU fire relies on a dedicated extinguishing bottle containing Halon that feeds directly into the APU compartment. This bottle is sized and plumbed specifically for the APU bay, so when it’s discharged you get the right agent concentration exactly where the fire is burning, without wasting extinguishant in other areas. That targeted delivery is essential because the APU bay is a confined space with its own heat sources and materials. Using the main cockpit bottle, a water mist system, or a handheld extinguisher won’t provide the correct reach, concentration, or quantity for the APU enclosure, and could fail to suppress the fire effectively or cause damage to sensitive systems. Therefore, the extinguishing method is the APU-dedicated Halon bottle.