Which action is taken when the APU fire push sequence is engaged regarding fuel?

Which action is taken when the APU fire push sequence is engaged regarding fuel?

• A. Pump for the fuel turns off
• B. Fuel lines are purged to atmosphere
• C. Fuel control unit increases fuel flow
• D. High-pressure fuel pump begins to operate at higher pressure

Answer: (A)

When the APU fire push is activated, the immediate action is to stop fuel delivery to the APU. Turning off the fuel pump severs the fuel supply, starving the APU of fuel and helping to prevent the fire from continuing to burn. This is the correct approach because allowing fuel to continue to flow would feed the flame, making the fire harder to control. Purging fuel lines to atmosphere isn’t part of the fire push sequence and could release vapors without actually stopping the fire. Likewise, increasing fuel flow or raising the high-pressure pump would worsen the situation by feeding the flames.

When the APU fire push is activated, the immediate action is to stop fuel delivery to the APU. Turning off the fuel pump severs the fuel supply, starving the APU of fuel and helping to prevent the fire from continuing to burn. This is the correct approach because allowing fuel to continue to flow would feed the flame, making the fire harder to control. Purging fuel lines to atmosphere isn’t part of the fire push sequence and could release vapors without actually stopping the fire. Likewise, increasing fuel flow or raising the high-pressure pump would worsen the situation by feeding the flames.