Oral: APU Questions Flashcards Preview

Mesa ERJ class 5/9/18 > Oral: APU Questions > Flashcards

Flashcards in Oral: APU Questions Deck (13)
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1
Q

What kind of APU is on the aircraft?

A

Sundstrand APS 2300

2
Q

Describe the APU

A
  • Constant speed
  • Single-stage impeller with a 2-stage axial-flow turbine
  • Independent oil system
3
Q

What controls the APU?

A

•A dedicated FADEC

4
Q

What battery is used for the APU start?

A
  • BATT 2 powers the starter

* BATT 1 powers the FADEC and EICAS for monitoring

5
Q

What is the fuel source for the APU?

A
  • Right fuel tank

* Left fuel tank through the crossfeed valve

6
Q

What fuel pump is used for APU start?

A
  • Batteries ‘ON’ only DC fuel pump in right tank
  • AC powered airplane ACMP 2
  • Right engine running Ejector fuel pump
7
Q

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

A

Yes

8
Q

What does moving the APU start switch to ‘OFF’ do?

A
  • Initiates normal APU shutdown
  • 1-minute cool down
  • No pneumatics (electrics only for 1 minute)
9
Q

Can the APU shutdown be cancelled?

A

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

10
Q

How is the APU shutdown immediately?

A
  • APU emergency stop button

* No 1-minute cool down period

11
Q

What will happen if batteries are turned OFF during the 1-minute cool-down period?

A

APU will shut down immediately

12
Q

When will automatic shutdown of the APU occur?

a] Ground:

b] Flight:

A

a] Ground:

  1. Overspeed
  2. Underspeed
  3. FADEC critical fault
  4. Fire
  5. Overheat
  6. High oil temperature
  7. Low oil pressure
  8. Sensor failure

b] Flight:

  1. Overspeed
  2. Underspeed
  3. FADEC critical fault
13
Q

Can the APU be started after a critical fault?

A

No