APU

Question 1

What type of APU is used on the CRJ 900

Answer 1

Allied Signal RE 220

Question 2

What are the priorities of the APU

Answer 2

Electrical first

Pneumatic second

Question 3

Max APU generator load

Answer 3

40 KVA at 41,000 feet

Question 4

Max operating altitude for the APU

Answer 4

41,000 feet

Question 5

Max altitude for starting the APU

Answer 5

37,000 feet

Question 6

Max altitude for APU bleed air extraction

Answer 6

25,000 feet

Question 7

Max speed with APU door open

Answer 7

220 KIAS if APU not operating

Vmo, Mmo is APU is operating

Question 8

Minimum battery voltage required before starting the APU

Answer 8

22 volts on both the main and APU battery

Question 9

What does the main battery power during APU start

Answer 9

APU Electrical Control Unit (ECU)

Question 10

What does the APU bettery power during APU start

Answer 10

The 28 volt DC APU start motor

Question 11

When will the START portion of the START/STOP switchlight extinguish

Answer 11

46-60% APU RPM

Question 12

When will the AVAIL portion of the START/STOP switchlight illuminate

Answer 12

99% RPM plus 2 seconds

Question 13

What are the APU starter limits

Answer 13

No more than 3 start attempts in one hour

2 minute delay required between start attempts