PNEUMATICS

Question 1

From where is bleed air obtained?

Answer 1

from the engine compressors and the APU on the ground

Question 2

When does HP air enter the system?

Answer 2

Generally on the ground (low power settings, <30-40%)

Question 3

What controls opening and closing of the HP valve?

Answer 3

The high pressure switches

Question 4

Can all bleed requirements be met with one engine shut down?

Answer 4

Yes

Question 5

What are the functions of the flow rate controller (300)?

Answer 5

controls the quantity of air supplied form the packs. in a 200 min causes only the flight compartment to get air

Question 6

How does an over-heat affect the system?

Answer 6

The bleed hot caution will illuminate and the a full cold signal will be sent to the trimming valves. if it is a pack hot then the valve will close

Question 7

After an over-heat, does the system have to be manually reset?

Answer 7

No, if a pack overheats it will come back on again once the condition not longer exists

Question 8

From where in the system is de-icing air tapped?

Answer 8

Prior to the nacelle shut off valve

Question 9

What happens to the bleed system in the event of an electrical failure?

Answer 9

HP valve closes and the LP remains open with the nacelle shut off.

Question 10

What is the function of the HBOV?

Answer 10

Prevents compressor surge/stall by venting excess bleed air overboard, controlled by the EEC/ECU