APU Panel

Question 1

What does the APU MASTER SW pb to ON do?

Answer 1

• Electrically powers the APU system (Blue ON light in pb)
• ECB performs a power up test
• APU ECAM page appears (if EXT or ENG GEN AC power is available)
• APU air intake flap opens
• APU fuel isolation valve opens
• APU fuel pump operates (if no tank pumps are on)

Question 2

What happens when you push the APU START pb?

Answer 2

• Blue ON light illuminates
• When APU air intake flap opens the starter is energized
• Ignition is turned ON 1.5 seconds after starter is energized
• Starter is de-energized and ignition turned OFF at 55% N
• Blue ON light in START pb extinguishes
• Green AVAIL light illuminates 2 seconds after 95% N or above 99.5% N
• APU page disappears from the ECAM 10 seconds later

Question 3

With the APU running and supplying bleed air, how do you shut it down?

Answer 3

• APU BLEED pb OFF
• APU MASTER SW OFF
• APU will cool down and then shut down

Question 4

What does the green AVAIL light on the APU START pb indicate?

Answer 4

The APU is available to provide electrical power and/or bleed air

Question 5

With the APU green AVAIL light ON and the EXT PWR green AVAIL light on, which system is powering the
aircraft?

Answer 5

APU

Question 6

If the APU is running, is it necessary to manually select APU BLEED OFF prior to APU shutdown?

Answer 6

No. When the APU MASTER SW is selected OFF, the bleed air valve is closed and the APU is allowed to cool prior to shutdown

Question 7

During the cool down cycle can you still use the APU?

Answer 7

Yes, press the APU MASTER SW pb

Question 8

An amber FAULT light in the APU MASTER SW pb indicates?

Answer 8

An APU auto shutdown has occurred

Question 9

What does an amber FAULT light in the APU BLEED pb mean?

Answer 9

An APU bleed leak

Question 10

Does APU air or electric have priority?

Answer 10

Electric