APU

Question 1

Purpose of APU (ground / take off / in flight)

Answer 1

On the ground:

1. Bleed Air for engine start
2. Air Con
3. Power to electrical system [via its own generator
4. Has own pneumatic supply

Take-off

1. If optimum performance required - APU can be used for Air Con

In flight

1. Backup for electrical system
2. Bleed air for air con
3. Assist engine starting

Question 2

Air Intake Flap key facts:

Answer 2

1. Located bottom of tailcone
2. Electrically operated
3. Ducts external air to the compressor inlet
4. “Flap open” displayed on ECAM APU page

Question 3

How is Fuel flow provided for the APU?

Answer 3

1. Normally from left side fuel system
2. If unavailable, APU pump will start automatically

Question 4

APU oil

Answer 4

Complicated! Basic - uses its own independent integral lubrication system (for lubrication and cooling)

Question 5

APU Bleed System. How is it engaged and what is it used for?

Answer 5

1. Engaged by APU BLEED pb
2. provides bleed air for:
   a) engine start
   b) air con
   c) pressurisation (pneumatics)
3. It has priority over engine bleed air

Question 6

What is the ECB and what does it do?

Answer 6

Electronic Control Box

1. Controls and Monitors all modes of APU operation includinga) start
   b) speed
   c) Temp
   d) shut down (auto and normal)

Question 7

Where is the smoke detector in the avionics bay?

Answer 7

Downwind of the avionics compartment