Global Express Auxiliary Power Unit (APU)

Question 1

What is the APU type?

Answer 1

RE 220

Question 2

What is the maximum APU RPM?

Answer 2

106 %

Question 3

What is the maximum altitude for APU operations?

Answer 3

45,000 feet

Question 4

Minimum temperature for starting a cold soaked APU?

Answer 4

-40° C

Question 5

How many start attempts are permitted on the APU?

Answer 5

3 per hour

Question 6

What is the maximum starting altitude for the APU?

Answer 6

37,000 feet

Question 7

What is the maximum altitude for bleed air extraction from the APU?

Answer 7

30,000 feet

Question 8

What is the maximum OAT for bleed air extraction from the APU for air conditioning operations?

Answer 8

> 45° C

Question 9

What is the max. load rating for the APU?

Answer 9

40 KVA

Question 10

What is the associated limit if the APU is powering an AC Bus above 37,000 Feet?

Answer 10

The associated Hydraulic pump (1B, 2B, 3B, 3A) must be selected “OFF”

Question 11

How is the APU controlled by the FADEC to ensure priority for electrical loads?

Answer 11

Cycling the Load Control Valve (LPV)

Question 12

When does the APU door position appear on the STAT page?

Answer 12

In conjunction with an APU DOOR FAIL caution message

Question 13

When is it recommended to top up the APU oil reservoir?

Answer 13

STAT page indication shows less than

4.5 quarts

Question 14

What will occur if the APU run switch is selected to the “run” position prior to the 60 second cooldown period?

Answer 14

The APU returns to 100% and continues normal operation

Question 15

When is manual operation of the APU LCV not possible?

Answer 15

Anti-ice is active
Lt Eng pressure regulating valve is manually opened
Rt Eng pressure regulating valve and crossbleed valve are manually opened

Question 16

How is the APU controlled by the FADEC to ensure priority for electrical loads?

Answer 16

Cycling the Load Control Valve (LPV)

Question 17

How is emergency shutdown of the APU accomplished?

Answer 17

BATT MASTER switch selected OFF with no AC power on
APU fire DISCH handle pulled
APU SHUTOFF button (services panel)
APU compartment SHUTDOWN button

Question 18

When does the APU automatically shutdown in flight only?

Answer 18

FADEC failure or DC power loss
Inlet door uncommanded position
Loss of Overspeed protection 
Overspeed 106%
EGT Overtemperature 
Loss of speed signals
Slow start, no crank, no acceleration