APU

Question 1

What services does the APU provide

Answer 1

Electric generator 28V dc, pneumatic power for engine start, bleed air for the air conditioning pack

Question 2

How is the APU controlled and monitored?

Answer 2

Full Authority Digital Electronic Control unit FADEC

Question 3

What does pressing the APU on/off button do?

Answer 3

Starts the ECU power up sequence and initiates the APU built in test BIT (START button will flash green)

Question 4

When will the APU START button glow steady green?

Answer 4

When APU is ready to start

Question 5

APU START button is Amber, that means…

Answer 5

APU start is inhibited

Question 6

APU starter limitations

Answer 6

3 consecutive unsuccessful attempts with 30 sec between each

Question 7

Which MFD page has APU info?

Answer 7

STATUS synoptic page

Question 8

Which tank normally fuels the APU

Answer 8

Right tank

Question 9

Can the APU be fueled from the left tank?

Answer 9

Yes, via the Xfeed system

Question 10

Can the APU supply bleed air on the ground and inflight?

Answer 10

Yes

Question 11

If the APU is the only source of power what buses can it power on the ground? Inflight?

Answer 11

Entire electrical load and battery charging

Inflight = no SHED buses

Question 12

APU altitude limitations

Answer 12

31,000 for start, operation, and power supply

23,000 engine start

Question 13

Where does the APU get its power for start?

Answer 13

Battery 2

Question 14

What should you see on the STATUS synoptic page if the APU oil quantity is good?

Answer 14

A green OK

Question 15

4 conditions that cause APU to auto shutdown

Answer 15

Overspeed, underspeed, ECU internal failure, APU bleed leak

Question 16

Conditions that cause APU to auto shutdown on ground only

Answer 16

Fire, EGT overtemp, high oil temp, low oil pressure, starter not engaged, fuel shutoff valve fail