APU RKA Questions

Question 1

What services does the APU provide and what are they used for?

Answer 1

1. 28V DC to the Electrical System
2. Pneumatic Power is used for:
   a. Engine Starting
   b. Supply Bleed Air to the Air Conditioning Pack of the Environmental Control System (ECS) (AOM 9-04-01)

Question 2

How is the APU controlled and monitored?

Answer 2

• Through a dedicated Electronic Control Unit (AOM 9-04-01)

Question 3

What does pressing the APU ON/OFF button do?

Answer 3

1. It starts the ECU power-up sequence
2. Initiates the APU Built-In Test (BIT)

(AOM 9-04-30)

Question 4

When does the START button on the APU CONTROL panel flash green?

Answer 4

• During the ECU BIT test (AOM 9-04-30}

Question 5

What does the START button on the APU control panel illuminating steady green indicate?

Answer 5

• The APU is available to start (AOM 9-04-30)

Question 6

If the START button on the APU control panel illuminates Amber, what does that indicate?

Answer 6

• The APU start is inhibited (AOM 9-04-30)

Question 7

What are the APU starter limitations?

Answer 7

1. Up to (3) consecutive unsuccessful start attempts are allowed
2. 30-second intervals between attempts
   (AOM 2-38)

Question 8

What MFD page can APU information be seen on?

Answer 8

• The STATUS synoptic page (AOM 9-04-30)

Question 9

Which tank normally supplies fuel to the APU?

Answer 9

• The right tank (AOM 9-04-50)

Question 10

Is it possible to feed the APU from the left wing tank? If so, how?

Answer 10

• Yes, via the cross-feed system (AOM 9-04-50)

Question 11

Can the APU supply bleed air on the ground or in flight?

Answer 11

• Yes (AOM 9-04-50)

Question 12

On the ground, what is the primary source of pneumatic air?

Answer 12

• The APU (AOM 9-04-50)

Question 13

If the APU is the only source of electrical power on the ground, what buses can the APU power?

Answer 13

• All the airplane electrical loads and charge both batteries (AOM 9-04-50)

Question 14

If the APU is the only source of electrical power in flight, what buses can the APU power?

Answer 14

• All electrical loads (except for the SHED BUSES) and also charging both batteries (AOM 9-04-50)

Question 15

Up to what altitude can the APU be started?

Answer 15

• Up to 31 ,000 ft (AOM 9-04-50 & AOM 2-38)

Question 16

Up to what altitude is the APU able to supply bleed air for engine starting?

Answer 16

• Up to 23,000 ft (AOM 9-04-50 & AOM 2-38)

Question 17

Up to what altitude is the APU able to supply bleed air for ECS?

Answer 17

• Up to 20,000 ft (AOM 9-04-50 & AOM 2-38)

Question 18

Where does the APU get it’s power for starting?

Answer 18

• The #2 BATT (AOM 9-04-50)

Question 19

What should be displayed on the STATUS synoptic page if the APU oil quantity is sufficient?

Answer 19

• A green “OK” (AOM 3-01-10)

Question 20

List the 4 conditions that will cause the APU to Automatically Shut Down either in Flight (or) on the Ground:

Answer 20

1. Overspeed
2. Underspeed
3. ECU Internal failure
4. APU Bleed leak (AOM 9-04-50)

Question 21

List the conditions that will cause the APU to automatically shut down on the ground only:

Answer 21

1. APU Fire
2. APU EGT over temperature
3. APU high oil temperature
4. APU low oil pressure
5. APU starter not disengaged
6. APU fuel SOV failure

(AOM 9-04-50)