APU

Question 1

What is the max airspeed to start the APU?

Answer 1

285KIAS

Question 2

Can the APU be used to heat the aircraft during anti ice application?

Answer 2

No

Question 3

What is the max altitude at which the APU provides bleed air ?

Answer 3

20000ft

Question 4

What is the max certified operating altitude for the APU?

Answer 4

37000 ft

Question 5

What is the primary purpose of the APU

load control valve ?

Answer 5

To prevent Overtemperature condition

Question 6

What is the limitation for extraction of bleed air from the APU for engine start and environmental air?

Answer 6

20000 ft

Question 7

What is the max altitude for APU generator use?

Answer 7

30000ft

Question 8

What is the max altitude for APU start ?

Answer 8

30000 ft

14000 on ground

Question 9

What is the max speed for starting the APU?

Answer 9

285 KIAS

Question 10

In addition to operating the gear mounted generator, what is the other purpose for the APU?

Answer 10

Airconditioning / pressurization and engine start

Question 11

When does the APU surge valve extract air from the APU?

Answer 11

When the load control valve is not open, and air must be removed from the compressor to prevent compressor stall

Question 12

Where does the APU obtain fuel for operation ?

Answer 12

From the right wing collector tank.

Question 13

On the ground how is the APU remotely shut down?

Answer 13

Remote cutoff switch located behind the external power access door

Question 14

Can the APU be used during de/anti icing procedures ?

Answer 14

No

Question 15

What is the limitation for left engine starting on the ground using bleed air ?

Answer 15

9000 ft

Question 16

During APU start, the crew must abort the start if the APU RPM is less than 30% after how long?

Answer 16

30 sec

Question 17

What are the cooling time limitations for APU starts on the ground?

Answer 17

One minute between the first 2 start attempts and 20 minutes after the 3rd

Question 18

Is another start attempt permitted after an unsuccessful APU start attempt in the air ?

Answer 18

No

Do not attempt another start until after landing

Question 19

What are the memory items for an APU fire on the ground?

Answer 19

None.

Automatic fire suppression and shutoff

Question 20

The APU operates the gearbox mounted generator , supplies bleed air for air conditioning and pressurization , and _____

Answer 20

Main engine starting

Question 21

Following an unsuccessful start or a hung start of an APU in flight, can a second start attempt be made after observing a one minute cooking period?

Answer 21

No

Question 22

The ______ panel allows the selection of the APU as the bleed air source.

Answer 22

AIR COND/ BLEED PANEL

Question 23

Where is the APU cutoff switch located ?

Answer 23

Right side , aft of wing behind electrical connection access door

Question 24

Which fuel pump delivers fuel under pressure to the APU fuel control unit?

Answer 24

Right DC Fuel pump

Question 25

The APU bleed valve controls airflow to the aircraft bleed air system and protects the APU from _______

Answer 25

Over temperature condition

Question 26

Is it possible that the surge valve may cause a noticeable hissing type sound in the APU area ?

Answer 26

Yes

Question 27

Which synoptic pages monitor the APU system and services ?

Answer 27

Fuel
Electrical
ECS