APU

Question 1

What kind of APU is on the plane?

Answer 1

Sundstrand APS 2300

Question 2

describe the APU?

Answer 2

• Constant speed
• single stage impeller with a 2 stage axial flow turbine
• independent oil system

Question 3

what controls the APU?

Answer 3

a dedicated FADEC

Question 4

what battery is used for the APU start?

Answer 4

• BATT 2 powers the started

- BATT 1 powers the FADEC and EICAS for monitoring

Question 5

what is the fuel source for the APU?

Answer 5

• right fuel tank

- left fuel tank through the xfeed valve

Question 6

what fuel pump is used for the APU start?

Answer 6

look on study guide for chart

Question 7

will the APU shutdown automatically if speed and acceleration rate isn’t reached in starting cycle time?

Answer 7

Yes

Question 8

what does moving the APU start switch to “OFF” do?

Answer 8

• inneciates a normal shutdown
• 1 minute cooldown
• no pneumatics (electrics only for 1 min)

Question 9

can the APU shutdown be cancelled?

Answer 9

Yes, by moving the START switch back to ON before the 1-min cool down is over

Question 10

how is the APU shutdown immediately

Answer 10

• APU emergency stop button

- No 1-minute cool down period

Question 11

what will happen if batteries are turned OFF during the 1-min cool down period?

Answer 11

APU will shut down immediately

Question 12

When will automatic shutdown of the APU occur?

Answer 12

-Ground
overspeed-under speed-FADEC critical fault-fire-EGT overheat-Low oil pressure-high oil pressure-sensor fault
Flight-
overspeed-underspeed-FADEC critical fault

Question 13

Can the APU be started after a critical fault?

Answer 13

NO