APU Limitations

Question 1

What is the operating limitation of the APU if the LOW OIL LEVEL ECAM advisory is displayed?

Answer 1

The APU maybe started and operated even if the message is displayed.

However, maintenance action is required within the time limits specified in LIM chapter

Question 2

What is the limitation regarding consecutive start attempts of the APU?

Answer 2

After 3 consecutive start attempts (duty cycles) , a 60-minute cool down is required before the next start.

Question 3

What is the APU EGT limit for any phase of operation?

Answer 3

The red line limit on the EGT scale

Question 4

What is the minimum battery voltage to start the APU?

Answer 4

25.5 V with BATT sw OFF

If not elec. powered for 6hrs or more

Question 5

What is the maximum altitude for starting (using an engine generator) and using the APU for electric power ?

Answer 5

Aircraft Ceiling

Question 6

What is the maximum altitude for attempting an APU start with the aircraft batteries only (ELEC EMER CONFIG )

Answer 6

25,000 ft

Question 7

What is the maximum altitude for using the APU Bleed with ONE Pack?

Answer 7

22,500 ft

Question 8

What is the maximum altitude to use the APU Bleed for an Engine start?

Answer 8

20,000ft

Question 9

What is the maximum altitude for using APU Bleed with Two Packs?

Answer 9

15,000 ft

Question 10

What is the limitation of the APU regarding the use of wing anti-ice?

Answer 10

APU air bleed extraction for wing anti-ice is not permitted